2015 CAP Congress / Congrès de l'ACP 2015

America/Edmonton
University of Alberta

University of Alberta

Edmonton, AB
Description

The 2015 CAP Congress is being hosted by University of Alberta, June 15-19, 2015. This Congress is an opportunity to showcase and celebrate the achievements of physicists in Canada and abroad. Mark your calendars and bookmark the main Congress web site (http://www.cap.ca/en/congress/2015 ) for easy access to updates and program information.

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Link to online registration:  https://www.cap.ca/CAP_Meetings/default.aspx

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Le Congrès 2015 de l'ACP se tiendra à la University of Alberta (Edmonton) du 15 au 19 juin 2015. Au cours de cet événement nous pourrons profiter des présentations et des réalisations de physiciens et physiciennes du Canada et d'ailleurs, et les célébrer. Inscrivez la date du congrès à votre agenda et créez un signet de l'adresse du site web du congrès (http://www.cap.ca/fr/congress/2015) pour accéder facilement aux mises à jour et au contenu de la programmation.

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2015 CAP Congress Poster
    • CINP Town Hall (Sat) / Consultation publique du ICPN CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Prof. Garth Huber (University of Regina)
      • 1
        Welcome & Introduction
        Speaker: Garth Huber (University of Regina)
        Slides
      • 15:07
        Coffee and Discussion
      • 2
        Discussion on Hadron Structure/QCD (21)
      • 3
        Discussion on HQP Issues (40)
        Speaker: Juliette Mammei
    • CINP Town Hall (Sat) / Consultation publique du ICPN: FUNDAMENTAL SYMMETRIES I
      Convener: Gerald Gwinner
      • 4
        ALPHA Antihydrogen Symmetry Test (20+5)
        Slides
      • 5
        MOLLER Parity Violation Experiment at JLab (20+5)
        Slides
      • 6
        Cold Neutrons at SNS (10+2)
        Slides
      • 7
        UltraCold Neutrons at TRIUMF (20+5)
        Slides
    • CINP Town Hall (Sat) / Consultation publique du ICPN: Hadron Structure/QCD
      Convener: Adam Garnsworthy
      • 8
        Compton Scattering Measurements at MAMI (15+3)
        Speaker: Prof. David Hornidge (Mount Allison University)
        Slides
      • 9
        Nucleon electromagnetic form factor measurements at JLab (15+3)
        Speaker: Adam Sarty (Saint Mary's University)
        Slides
      • 10
        The GlueX and Exclusive Meson Production Programs at JLab (20+5)
        Slides
      • 11
        Extreme QCD: Characterizing the Quark-Gluon Plasma (15+3)
        Speaker: Prof. Charles Gale (McGill University)
        Slides
    • CAP Board Meeting (Old and New) / Réunion du CA de l'ACP (ancien et nouveau) CCIS 3-003

      CCIS 3-003

      University of Alberta

    • Long Range Planning Committee Kick-off Meeting / Reunion du comite de planification a long terme CCIS 4-003

      CCIS 4-003

      University of Alberta

    • IPP Town Hall - AGM / Consultation publique et AGA de l'IPP NINT Taylor Room

      NINT Taylor Room

      University of Alberta

      Convener: Michael Roney (University of Victoria)
      • 12
        Introduction-IPP Director's Report
        Speaker: Michael Roney (University of Victoria)
        Slides
      • 13
        Particle Astrophysics CFREF
        Speaker: Prof. Tony Noble (Queen's University)
        Slides
      • 14
        DEAP
        Speaker: Mark Boulay (Q)
        Slides
      • 15
        SNO+
        Speaker: Christine Kraus
        Slides
      • 16
        SuperCDMS
        Speaker: Prof. Gilles Gerbier (Queen's University)
        Slides
      • 17
        PICO
        Speaker: Tony Noble (Queen's University)
        Slides
      • 18
        EXO
        Speaker: Prof. David Sinclair (Carleton University)
      • 19
        NEWS Experiment
        Speaker: Prof. Gilles Gerbier (Queens' University)
        Slides
      • 12:30
        LUNCH
      • 20
        IceCube
        Speaker: Prof. Darren Grant (University of Alberta)
        Slides
      • 21
        Theory review-Higgs, EW, BSM
        Speakers: Dr David Morrissey (TRIUMF), Prof. Heather Logan (Carleton University)
        Slides
      • 22
        Moller Experiment at JLAB
        Speaker: Michael Gericke (University of Manitoba)
        Slides
      • 23
        ALPHA
        Speaker: Makoto Fujiwara (TRIUMF (CA))
        Slides
      • 24
        UCN
        Speaker: Prof. Jeffery Martin (University of Winnipeg)
        Slides
      • 25
        Belle II
        Speaker: Dr Christopher Hearty (IPP / UBC)
        Slides
      • 26
        HEPNET/Computing in HEP
        Speaker: Randy Sobie (University of Victoria (CA))
        Slides
      • 15:10
        BREAK
      • 27
        MRS - Alberta/Toronto
        Speaker: James Pinfold (University of Alberta (CA))
        Slides
      • 28
        MRS - Carleton/Victoria/Queens
        Speaker: Prof. Kevin Graham (Carleton University)
        Slides
      • 29
        NA62
        Speaker: Dr Toshio Numao
        Slides
      • 30
        Halo+upgrade at LNGS
        Speaker: Prof. Clarence Virtue (Laurentian University)
        Slides
      • 31
        VERITAS
        Speaker: Prof. David Hanna (McGill University)
        Slides
      • 32
        g-2 at JPARC
        Speaker: Dr Glen Marshall (TRIUMF)
        Slides
      • 33
        Theory Review - QCD
        Speaker: Prof. Randy Lewis (York University)
        Slides
      • 34
        ATLAS
        Speaker: Prof. Alison Lister (UBC)
        Slides
      • 35
        Technical support for experiment development and construction
        Speaker: Dr Fabrice Retiere (TRIUMF)
        Slides
    • CINP Town Hall (Sun) / Consultation publique du ICPN CCIS L1-029

      CCIS L1-029

      University of Alberta

      Convener: Prof. Garth Huber (University of Regina)
      slides
      • 36
        Introductory Comments
        Speaker: Garth Huber (University of Regina)
        Slides
      • 12:08
        Lunch (provided)
      • 37
        Discussion on Nuclear Astrophysics (19)
        Speaker: Iris Dillmann
      • 38
        Discussion on Nuclear Structure (20)
        Speaker: Adam Garnsworthy
      • 15:00
        Coffee
      • 39
        Discussion on Fundamental Symmetries (20)
      • 40
        General Discussion
        Speaker: Garth Huber (University of Regina)
    • CINP Town Hall (Sun) / Consultation publique du ICPN: NUCLEAR STRUCTURE & ASTROPHYSICS I
      Convener: Garth Huber (University of Regina)
      slides
      • 41
        Nuclear Structure aspects of the Gamma-Ray program (20+5)
      • 42
        Nuclear Astrophysics aspects of the Gamma-Ray program (20+5)
        Speaker: iris Dillmann
      • 43
        Fundamental Symmetries aspects of the Gamma-Ray program (20+5)
        Speaker: Carl Svensson
      • 44
        Nuclear Astrophysics with DRAGON/TUDA/EMMA (15+3)
        Speaker: Chris Ruiz (TRIUMF)
      • 45
        TITAN Ion Trap Program at ISAC (20+5)
        Slides
    • CAP Advisory Council (Old and New) / Conseil consultatif de l'ACP (ancien et nouveau) CCIS L1-029

      CCIS L1-029

      University of Alberta

    • CINP Town Hall (Sun) / Consultation publique du ICPN: NUCLEAR STRUCTURE & ASTROPHYSICS II
      Convener: Charles Gale
      slides
      • 46
        Canadian Penning Trap & Related Ion-Trap Expts @ ANL (15+3)
      • 47
        Reaction spectroscopy of rare isotopes with low and high-energy beams (15+3)
        Speaker: Rituparna Kanungo (TRIUMF)
      • 48
        Electroweak measurements of nuclear neutron densities via PREX and CREX at JLab (15+3)
        Speaker: Juliette Mammei (University of Manitoba)
      • 49
        Ab initio nuclear theory for structure and reactions (20+5)
        Speaker: Francesco Raimondi
        Slides
      • 50
        From nuclear forces to structure and astrophysics (10+2)
        Speaker: Alexandros Gezerlis
    • CINP Town Hall (Sun) / Consultation publique du ICPN: FUNDAMENTAL SYMMETRIES II
      Convener: Iris Dillmann
      slides
      • 51
        TRIUMF's Neutral Atom Trap for Beta Decay (15+3)
        Slides
      • 52
        Francium Trap Project (15+3)
      • 53
        Neutrinoless Double Beta Decay (25+5)
        Speaker: David Sinclair
        Slides
      • 54
        Electroweak Physics (15+3)
        Slides
    • CINP Town Hall (Sun) / Consultation publique du ICPN: New Facilities
      Convener: Juliette Mammei
      slides
      • 55
        Science Opportunities of ARIEL (20+5)
      • 56
        Resources for Detector Development in the Canadian Subatomic Physics Community (10+2)
    • CINP Board Meeting / Réunion du conseil de l'ICPN CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Prof. Garth Huber (University of Regina)
    • IPP Inst. Members and Board of Trustees Meetings / Réunions des membres inst. et du conseil de l'IPP NINT Taylor Room

      NINT Taylor Room

      University of Alberta

      Convener: Michael Roney (University of Victoria)
    • Joint CINP-IPP Meeting / Réunion conjointe de l'ICPN et de l'IPP (DPN-PPD) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Conveners: Prof. Garth Huber (University of Regina), Michael Roney (University of Victoria)
      • 57
        Report from NSERC SAP ES
        Speaker: John Martin (York University (CA))
        Slides
      • 58
        Canada Foundation for Innovation and Subatomic Physics
        Speaker: Olivier Gagnon (Fondation canadienne pour l'innovation)
        Slides
      • 59
        Report from TRIUMF Director
        Speaker: Jonathan Bagger (Johns Hopkins University)
        Slides
      • 60
        Report from SNOLAB Director
        Speaker: Nigel Smith (SNOLab)
        Slides
      • 61
        Report from Subatomic Physics Long Range Plan Committee Chair
        Speaker: Dean Karlen (University of Victoria (CA))
        Slides
    • PiC Editorial Board Meeting / Réunion du Comité de rédaction de La Physique au Canada CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Bela Joos (University of Ottawa)
    • IPP / CINP Health Break / Pause santé IPP / ICPN CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • CINP Annual General Meeting / Assemblée générale annuelle de l'ICPN CCIS L1-029

      CCIS L1-029

      University of Alberta

      Convener: Prof. Garth Huber (University of Regina)
      slides
    • IPP Town Hall - AGM / Consultation publique et AGA de l'IPP CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Michael Roney (University of Victoria)
      • 62
        Status and future plan of KEK and J-PARC
        Speaker: Yasuhiro Okada (KEK)
        Slides
      • 63
        T2K+HyperK
        Speaker: Hirohisa A. Tanaka (University of British Columbia)
        Slides
      • 64
        ILC
        Speaker: Alain Bellerive (Carleton University (CA))
        Slides
      • 65
        Long Range Plan: Next Steps for IPP
        Speaker: Michael Roney (University of Victoria)
        Slides
    • Lunch / Diner
    • M-PLEN Plenary Session - Start of Conference - Sara Seager, MIT / Session plénière - Ouverture du Congrès - Sara Seager, MIT CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Robert Fedosejevs (University of Alberta)
    • M1-1 Topological States of Matter (DCMMP) / États topologiques de la matière (DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Kaori Tanaka (University of Saskatchewan)
      • 67
        Nematic and non-Fermi liquid phases of systems with quadratic band crossing
        I will review the recent work on the phases and quantum phase transitions in the electronic systems that feature the parabolic band touching at the Fermi level, the celebrated and well-studied example of which is the bilayer graphene. In particular, it will be argued that such three-dimensional systems are in principle unstable towards the spontaneous formation of the (topological) Mott insulator at weak long-range Coulomb interaction. The mechanism of the instability can be understood as the collision of non-Fermi liquid fixed point, discovered by Abrikosov in the `70s, with another, critical, fixed point, which approaches it in the coupling space as the system's dimensionality reaches certain ``critical dimension" from above. Some universal characteristics of this scenario, the width of the non-Fermi liquid crossover regime, and the observability of the nematic Mott phase in common gapless semiconductors such as gray tin or mercury tellurude will be discussed.
        Speaker: Prof. Igor Herbut (Simon Fraser University)
        Slides
      • 68
        Collective modes and interacting Majorana fermions in topological superfluids
        Topological phases of matter are characterized by the absence of low-energy bulk excitations and the presence of robust gapless surface states. A prime example is the three-dimensional (3D) topological band insulator, which exhibits a bulk insulating gap but supports gapless 2D Dirac fermions on its surface. This physics is ultimately a consequence of spin-orbit coupling, a single-particle effect within the reach of the band theory of solids. The phenomenology of topological superfluids (and superconductors, which are charged superfluids) is rather similar, with a bulk pairing gap and gapless 2D surface Majorana fermions. The standard theory of topological superfluids exploits this analogy and can be thought of as a band theory of Bogoliubov quasiparticles. In particular, this theory predicts that Majorana fermions should be noninteracting particles. Band insulators and superfluids are, however, fundamentally different: While the former exist in the absence of interparticle interactions, the latter are broken-symmetry states that owe their very existence to such interactions. In particular, unlike the static energy gap of a band insulator, the gap in a superfluid is due to a dynamical order parameter that is subject to both thermal and quantum fluctuations. In this talk, I will argue that order parameter fluctuations in a topological superfluid can induce effective interactions among surface Majorana fermions. Possible consequences of these interactions will be discussed.
        Speaker: Joseph Maciejko (University of Alberta)
        Slides
      • 69
        Dilute limit of an interacting spin-orbit coupled two-dimensional electron gas
        The combination of many-body interactions and Rashba spin-orbit coupling in a two-dimensional fermion system gives rise to an exotic array of phases in the ground state. In previous analyses, it has been found that in the low fermion density limit, these are nematic, ferromagnetic nematic, and spin-density wave phases. At ultra-low densities, the ground state favours the ferromagnetic nematic phase if the interactions are short range (contact), and the nematic phase if the interactions are long range (dipolar). In this talk, we examine interacting two-fermion systems with spin-orbit coupling. These systems retain the physics of the dilute limit of the many-body system, while allowing us to solve the ground state exactly for each type of interaction. We determine the symmetries of the ground state, which uniquely determine the phase of the system. These phases could potentially be observed in two-dimensional GaAs heterostructures with quantum wells that lack inversion symmetry.
        Speaker: Mr Joel Hutchinson (University of Alberta)
        Slides
      • 70
        Andreev and Josephson transport in InAs nanowire-based quantum dots
        Superconducting proximity effects are of fundamental interest and underlie recent proposals for experimental realization of topological states. Here we study superconductor-quantum dot- superconductor (S-QD-S) junctions formed by contacting short- channel InAs nanowire transistors with Nb leads. When the carrier density is low, one or more quantum dots form in the nanowire due to spatial potential fluctuations. Low-temperature electrical transport shows clear signatures of proximity superconductivity, such as regions of negative differential conductance, Multiple Andreev Reflections (MAR) and spectroscopic features hinting at the formation of Andreev Bound States (ABS). These features can coexist with the Coulomb diamond structure resulting from the dot charging energy. The theory of Andreev and Josephson transport in S-QD-S structures is invoked in order to elucidate the experimental data. Particular attention is devoted to an intermediate coupling regime, wherein the superconducting energy gap $\Delta$ is on the same order of magnitude as the tunnel coupling strength $\Gamma$, but smaller than the Coulomb charging energy of the dot $U$. In this model, a rich interplay exists between $U$, which favours a spin-doublet ground state for the quantum dot, $\Delta$, which favours a BCS- like singlet ground state, and Kondo correlations in the dot, which favour a Yu-Shiba-Rusinov-like singlet ground state. A quantum phase transition can occur from the doublet to the BCS- like singlet ground state, marking a $0$-$\pi$ transition in the Josephson current of the junction. The significance of these results to the search for topological states in semiconductor nanowire junctions is discussed.
        Speaker: Kaveh Gharavi (University of Waterloo)
        Slides
    • M1-10 NSERC's Partnership Program: Panel Discussion and Q&A / Programmes de partenariats du CRSNG : Table ronde et Q&R CAB 235

      CAB 235

      University of Alberta

      Convener: Bill Whelan (University of Prince Edward Island)
      • 71
        NSERC's Partnership Program: Panel Discussion and Q&A / Programme de partenariats du CRSNG : Table ronde et Q&R
        This session is a panel discussion and Q&A on researcher-industry collaborations and NSERC funding opportunities. Panelists include: Irene Mikawoz (NSERC Prairies Regional Office), Donna Strickland (U. of Waterloo), Wayne Hocking (Western U.), Kristin Poduska (Memorial U.), Chijin Xiao (U. of Saskatchewan) and Andranik Sarkissian (Plasmionique Inc). -- Cette séance consistera en un débat d’experts et en une période de questions sur les collaborations entre les chercheurs et l’industrie et sur les possibilités de financement du CRSNG. Au nombre des experts figurent Irene Mikawoz (Bur. régional des Prairies du CRSNG), Donna Strickland (U. de Waterloo), Wayne Hocking (U. Western), Kristin Poduska (U. Memorial), Chijin Xiao (U. de Saskatchewan) et Andranik Sarkissian (Plasmionique Inc).
    • M1-2 Organic and Molecular Electronics (DCMMP-DMBP-DSS) / Électronique organique et moléculaire (DPMCM-DPMB-DSS) CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Doug Bonn (Univ. of British Columbia)
      • 72
        Principles and methods enabling atom scale electronic circuitry
        Quantum dots are small entities, typically consisting of just a few thousands atoms, that in some ways act like a single atom. The constituent atoms in a dot coalesce their electronic properties to exhibit fairly simple and potentially very useful properties. It turns out that collectives of dots exhibit joint electronic properties of yet more interest. Unfortunately, though extremely small, the still considerable size of typical quantum dots puts a limit on how close multiple dots can be placed, and that in turn limits how strong the coupling between dots can be. Because inter-dot coupling is weak, properties of interest are only manifest at very low temperatures (milliKelvin). In this work the ultimate small quantum dot is described – we replace an “artificial atom” with a true atom - with great benefit. It is demonstrated that the zero-dimensional character of the silicon atom dangling bond (DB) state allows controlled formation and occupation of a new form of quantum dot assemblies - at room temperature. It is shown that fabrication geometry determines net electron occupation and tunnel-coupling strength within multi-DB ensembles and moreover that electrostatic separation of degenerate states allows controlled electron occupation within an ensemble. Single electron, single DB transport dynamics will be described as will conduction among collectives of DBs. Some results and speculation on the viability of a new “atomic electronics” based upon these results will be offered. As new technologies require new fabrication and analytical tools, a few words about robust, readily repairable, single atom tips will be offered too. This tip may be an ideal scanned probe fabrication tool.
        Speaker: Robert Wolkow (University of Alberta)
      • 73
        Polarization induced energy level shifts at organic semiconductor interfaces probed on the molecular scale by scanning tunnelling microscopy
        The inter- and intra- molecular energy transfer that underlies transport, charge separation for photovoltaics, and catalysis are influenced by both the spatial distribution of electronic states and their energy level alignment at interfaces. In organic materials, the relevant length scales are often on the order of a single molecular unit. Scanning tunneling microscopy (STM) and spectroscopy (STS) stands as one of few techniques with the ability to resolve both the spatial structure of these interfaces while probing energy levels on the nanometer scale. Here, we have used STM/STS in a spectroscopic mapping mode to investigate the spatial shifts in energy levels across well-defined 2-dimensional nanoscale clusters of 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA) decoupled from an Ag(111) substrate by a bilayer of NaCl. We find a striking difference between the HOMO and LUMO states of molecules residing at the edges of these clusters and those in the centre. Edge molecules exhibit a gap that is up to 0.5eV larger than observed for inner molecules. Most of this difference is accounted for by the shift of the occupied states, strongly influencing level alignment for a boundary region of single molecular width. As STS is a single-particle spectroscopy – adding or removing a charge – the energy levels measured are influenced by the local polarization environment. The shifts observed for several different geometries of islands correspond well with calculations of the stabilization of this transient charge via the polarization of the other molecules in the cluster. These effects are expected to influence organic semiconductors that exhibit hopping-like transport, and processes such as charge separation occurring at interfaces in organic photovoltaic devices. As the polarizability of most molecular semiconductors is anisotropic, the structure and orientation of molecules at interfaces will play a significant role in the resulting energy level alignment.
        Speaker: Sarah Burke (University of British Columbia)
      • 74
        On the Road to Low Power Circuitry: Analysis of Si Dangling Bond Charging Dynamics
        Undesired circuit heating results from the billions of electrons flowing through our devices every second. Heating wastes energy (leading to shorter battery life), and also puts a limit on computational speeds. The solution to excess heat generation is of huge commercial interest and has led to a large push towards nanoscale electronics which are smaller and more energy efficient. Proposed hybrid atom-scale schemes have already been formed to reduce power consumption of Complementary Metal Oxide Semiconductor (CMOS) chips commonly used in many consumer electronics including digital cameras and computers. At the heart of these schemes are atomic silicon dangling bonds (DBs) which can theoretically be used to form ultra-low power nanowires. In order to move towards the realization of these practical schemes, however, fundamental physical properties of DBs must first be characterized and studied. One of the properties inherent to DBs is their ability to store electrons. They can exist in a positive, neutral, or negative charge state when storing zero, one, or two electrons respectively. When imaging a DB with a scanning tunneling microscope (STM), fluctuations of the DB charge state can be observed that are driven by influence of the STM tip. A correlation analysis method adapted from biophysics was utilized to study these fluctuations in charge state to help uncover intrinsic transition rates between states for a given DB. Analysis such as this also opens the doors to study more complex systems of interacting DBs as well, which is another important step towards making practical devices.
        Speaker: Roshan Achal (University of Alberta)
      • 75
        Set Point Effects in Fourier Transform Scanning Tunneling Spectroscopy
        Fourier Transform Scanning Tunneling Spectroscopy (FT-STS) has become an important experimental tool for the study of electronic structure. By combining the local real space picture of the electronic density of states provided by scanning tunneling microscopy with the energy and momentum resolution of FT-STS one can extract information about the band structure and dispersion. This has been thoroughly demonstrated in studies of the superconducting cuprates, the iron arsenides, and heavy fermion compounds. FT-STS relies on the Fourier transform of the dI/dV, the derivative of the tunneling current with respect to the applied bias. Under the approximations of zero temperature, a flat tip density of states, and an energy independent tunneling matrix element it can be shown that the dI/dV signal is proportional to the local density of states of the sample. Under real experimental conditions, however, these approximations are not strictly valid, leading to additional functional dependencies of the dI/dV. A variety of artifacts can result when one considers the three most common measurement modes: constant current maps, constant height maps, and spectroscopic grids. We illustrate the different artifacts that can appear in FT-STS using data taken from the well understood surface state of an Ag(111) single crystal at 4.2 K and under ultra-high vacuum conditions. We find that constant current dI/dV maps taken with a lock-in amplifier lead to a feature in the FT-STS dispersion that disperses as a function of energy below the Fermi level (E$_F$) and becomes constant above E$_F$. This result shows the importance of distinguishing dispersing features caused by quasiparticles in the sample from those caused by the measurement. We compare the set point artifacts in all three modes of measurement to scattering model simulations based on the T-matrix formalism. Finally we propose a guide to help identify and isolate these set point artifacts for future studies in systems where the band structure and correlations create a complex scattering space.
        Speaker: Mr Andrew Macdonald (University of British Columbia)
    • M1-3 Theory, modelling and space weather I (DASP) / Théorie, modélisation et climat spatial I (DPAE) CAB 243

      CAB 243

      University of Alberta

      Convener: David Knudsen (University of Calgary)
      • 76
        Examples of exact solutions of charged particle motion in magnetic fields and their applications.
        There are very few exact solutions for the motion of a charged particle in specified magnetic field. These solutions have considerable theoretical as well as pedagogical value. In this talk I will briefly describe several known analytical solutions, such as motion in the equatorial plane of a dipole and in a constant gradient field. Particular attention will be given to a relatively unknown solution corresponding to magnetic field inversely proportional to the radius. This case leads to relatively simple expressions involving only elementary functions. I will discuss applications of this solution to validation of numerical methods of particle tracing, such as symplectic integration. Another interesting use of this solution is comparison with the adiabatic drift theory. Finally, this solution can be used as a building block for developing new numerical integration schemes for particle tracing.
        Speaker: Konstantin Kabin (RMC)
      • 77
        Energetic Electron Precipitation Model
        Energetic electron precipitations cause atmospheric ionization - a complicated process which depends on many parameters. We present our energetic particles precipitation model which consists of three main parts: Energetic electron sources; Coupled electron/photon transport in the earth atmosphere; RIOMETERs and Very Low Frequency (VLF) receivers response to energetic electron precipitations. The primary source of energetic electrons - Van-Allen radiation belts - occupy a vast region of space and accumulate an immense amount of energy. In the Northern hemisphere they map to a broad ring crossing Canada. Under certain conditions trapped electrons can penetrate even deeper into the atmosphere causing modulations of free electron densities of D-Layer. The model implements coupled electron/photon transport based on MCNP 6 general transport code. Model verification uses data from the Medium Energy Proton and Electron Detector instrument on NOAA's POES satellite. Calculated electron fluxes and estimated electron density altitudinal profiles are used to construct and validate a realistic transport model that maps energetic electron fluxes incident on the upper atmosphere to GO CANADA (RIOMETERs and VLF receivers) instrument responses.
        Speaker: Alexei Kouznetsov (University of Calgary)
        Slides
      • 78
        Properties of the lunar wake inferred from hybrid-kinetic simulations and an analytic model
        There is renewed interest in the Moon as a potential base for scientific experiments and space exploration. Earth's nearest neighbour is exposed directly to the solar wind and solar radiation, both of which present hazards to successful operations on the lunar surface. In this paper we present lunar wake simulation and analytic results and discuss them in the context of observations from the ARTEMIS mission. The simulation results are based on hybrid-kinetic simulations while the analytic model is based on the formalism developed by [Hutchinson, 2008]. The latter makes assumptions of cylindrical geometry, a strong and constant magnetic field, and fixed transverse velocity and temperature. Under these approximations the ion fluid equations (with massless electrons) can be solved analytically by the method of characteristics. In this paper the formalism presented by Hutchinson is applied by including plasma density variations and flow within the lunar wake. The approach is valid for arbitrary angles between the interplanetary magnetic field and solar wind velocity, and accounts for plasma entering the wake region from two tangent points around the Moon. Under this condition, two angle-dependent equations for ion fluid flow are obtained, which can be solved using the method of characteristics to provide the density inside the wake region. it is shown in Fig1 and Fig2 that the model provides excellent agreement with observations from the ARTEMIS mission [Angelopoulos, 2011], and with large-scale hybrid-kinetic plasma simulations [Paral and Rankin, 2012]. It will be shown that the analytic model provides a practical alternative to large-scale kinetic simulations, and that it is generally useful for determining properties of the lunar wake under different solar wind conditions. It will be useful as well for predicting properties of the plasma environment around the Moon that have not yet been visited by spacecraft. Acknowledgments. This work was partially supported by grants from the Canadian Space Agency and the Natural Sciences and Engineering Research Council of Canada (NSERC). The simulations also benefited from access to the Westgrid Compute Canada facilities. The ARTEMIS data for this paper are available at NASA’s Space Physics Data Facility (SPDF) (http://spdf.gsfc.nasa.gov/). Hossna Gharaee extends thank to THEMIS software manager Jim Lewis for his help on using ARTEMIS satellite data. -Hutchinson, I. (2008),Oblique ion collection in the drift approximation:How magnetized Mach probes really work, Physics Of Plasmas, 15, 123503, doi: 10.1063/1.3028314 -Angelopoulos, V. (2011), The ARTEMIS mission, Space Sci. Rev. (Netherlands), 165(1-4), 3–25. -Paral and Rankin (2012),Dawn-dusk asymmetry in the Kelvin-Helmholtz instability at Mercurry, Nature Communications, 4, 1645, doi:10.1038/ncomms2676,
        Speaker: Hossna Gharaee (university of Alberta, Departement of Physics)
      • 79
        Explaining the Newly Discovered Third Radiation Belt
        Accurate specification of the global distribution of ultra-low frequency (ULF) wave power in space is critical for determining the dynamics and acceleration of outer radiation belt electrons. Current radiation belt models use ULF wave radial diffusion coefficients which are analytic functions of Kp based on ULF wave statistics. In this presentation we show that these statistical based analytic models for the radial diffusion coefficients can produce electron flux values in surprising agreement with the observations during geomagnetically quiet intervals. However, during some storm intervals the radial diffusion rates derived directly from ULF wave observations can become orders of magnitude higher than those given by the analytic expressions based on ULF wave statistics. During these storm intervals only the radiation belt models driven by the radial diffusion coefficients derived directly from ULF wave measurements produce electron flux values in agreement with the observations. Utilizing Van Allen Probe data and CARISMA magnetometer data results will be presented of the electron flux obtained using the diffusion coefficients derived directly from the ULF wave measurements which shed new light on some interesting observations made by the Van Allen Probes
        Speaker: Dr Louis Ozeke (University of Alberta)
      • 80
        Fast damping of Alfven waves: Observations and modeling
        Results of analysis of Cluster spacecraft data will be presented that show that intense ultra-low frequency (ULF) waves in the inner magnetosphere can be excited by the impact of interplanetary shocks and solar wind dynamic pressure variations. The observations reveal that such waves can be damped away rapidly in a few tens of minutes. We examine mechanisms of ULF wave damping for two interplanetary shocks observed by Cluster on 7 November 2004, and 30 August 2001. The mechanisms considered are ionospheric joule heating, Landau damping, and waveguide energy propagation. It is shown that Landau damping provides the dominant ULF wave damping for the shock events of interest. It is further demonstrated that damping is caused by drift-bounce resonance with ions in the energy range of a few keV. Landau damping is shown to be more effective in the plasmasphere boundary layer due to the relatively higher proportion of Landau resonant ions that exist in that region. Moreover, multiple energy dispersion signatures of ions were found in the parallel and anti-parallel direction to the magnetic field immediately after the interplanetary shock impact in the November 2004 event. These dispersion signatures can be explained by flux modulations of local ions (rather than the ions from the Earth’s ionosphere) by ULF waves. Test particle simulations will be used to simulate the energy dispersions of particles caused by ULF waves. In our study, particles will be traced backward in time until they reach a region with known distribution function. Liouville’s theorem is then used to reconstruct the distribution function at the location of Cluster in a model magnetosphere.
        Speaker: Chengrui Wang (University of Alberta)
        Slides
    • M1-4 Theoretical Astrophysics (DTP) / Astrophysique théorique (DPT) CAB 239

      CAB 239

      University of Alberta

      Convener: Arundhati Dasgupta (University of Lethbridge)
      • 81
        Probing Physics with Observations of Neutron Stars and White Dwarfs
        White dwarfs and neutron stars are two of the densest objects in the Universe. Discovered 105 and 45 years ago, these objects are two of the best astrophysical laboratories of fundamental physics. The simple existence of white dwarfs is a stellar-size manifestation of quantum physics. I will describe how we use these objects today to study quantum-chromodynamics, quantum-electrodynamics, neutrino and axion physics and even thermodynamics in realms inaccessible to Earth-bound laboratories. In the process we also discover the detailed fate of our own Earth and Sun.
        Speaker: Jeremy Heyl (UBC)
        Slides
      • 82
        Observations and Theory of Supernova Explosions and their Remnants
        A supernova explosion occurs to end the life of a massive star (with mass of more than 8-10 times that of the sun). These explosions create and eject the elements that make up everything around us, including the earth. The life of a massive star will be outlined, and its sudden death in a supernova event. Following the explosion, the ejected material and energy interacts with the surrounding interstellar medium to produce a supernova remnant. Supernova remnants provide mass and kinetic energy to the interstellar medium, and accelerating most of the cosmic rays we observe. The observational aspects of supernova remnant will be reviewed and related to theoretical models.
        Speaker: Denis Leahy
        Slides
      • 83
        No "End of Greatness": Superlarge Structures and the Dawn of Brane Astronomy
        Several groups have recently reported observation of large scale structures which exceed the size limits expected from standard structure formation in a 13.8 billion years old LambdaCDM universe. On the other hand, the concept of crosstalk between overlapping 3-branes carrying gauge theories was recently introduced in arXiv:1502.03754[hep-th]. Crosstalk impacts the redshift of signals from brane overlap regions by making signals with the redshift z of the overlap region appear to have lower or higher redshift, depending on the electromagnetic crosstalk couplings. This leads to brane induced appearance of structure in redshift observations. The Lyman-alpha forest is a natural candidate to look for brane overlap at redshift z<6.
        Speaker: Dr Rainer Dick (University of Saskatchewan)
        Slides
    • M1-5 Nuclear Techniques in Medicine and Safety (DNP-DIAP) / Techniques nucléaires en médecine et en sécurité (DPN-DPIA) CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Zisis Papandreou (University of Regina)
      • 84
        Evaluation of SiPM Arrays and Use for Radioactivity Detection and Monitoring
        Silicon photomultipliers (SiPMs) are novel photo sensorss that are needed for many applications in a broad range of fields. The advantages of such detectors are that they feature low bias ($<$100V) operation, high gain (10$^5$ to 10$^6$), insensitivity to magnetic fields, excellent photon detection efficiency (PDE), and the ability to operate in field conditions over a range of temperatures; they are compact, easy to use, require simple electronics and can be produced commercially in various formats. To evaluate and operate SiPM Arrays, we developed novel techniques of measurement of the PDE, the cross-talk probability and the breakdown voltage for the SiPM-arrays with summed output, which is most popular type of SiPMs on the market; these techniques allow one to make the required measurements when the separation of individual photopeaks in the output spectrum (that was crucial for the "conventional" techniques used before) is not available. I will also present our study of prototypes of gross counting gamma and neutron detectors for first responders that use SiPMs coupled to appropriate scintillators.
        Speaker: Andrei Semenov
        Slides
      • 85
        Neutron Generator Facility at SFU - GEANT4 Dose Prediction and Verification
        A neutron generator facility under development at Simon Fraser University (SFU) utilizes a commercial deuterium- tritium neutron generator (Thermo Scientific P 385) to produce 14.2 MeV neutrons at a nominal rate of $3\times10^8$ neutrons/s. The facility will be used to produce radioisotopes to support a research program including nuclear structure studies and neutron activation analysis. As a prerequisite for regular operation of the facility and as a personnel safety consideration, dose rate predictions for the facility were implemented via the GEANT4 Monte-Carlo framework. Dose rate predictions were compared at two low neutron energy cutoffs: 5 keV and 1 meV, with the latter accounting for low energy thermal neutrons but requiring significantly more computation time. As the SFU facility geometry contains various openings through which thermal neutrons may penetrate, it was necessary to study their contribution to the overall dose rate. A radiation survey of the facility was performed as part of the commissioning process, consisting of a neutron flux measurement via copper foil activation and dose rate measurements throughout the facility via a $^3$He gas filled neutron detector (Thermo Scientific WENDI-2). When using the 1 meV low neutron energy cutoff to account for thermal neutrons in the dose rate predictions, the predictions and survey measurements agree to within a factor of 2 or better in most survey locations.
        Speaker: Mr Jonathan Williams (Simon Fraser University)
      • 86
        Rapid Elemental Analysis of Human Finger Nails Using Laser-Induced Breakdown Spectroscopy
        Zinc is a crucial element needed for many processes in the human body. It is essential for enzymatic activity and many cellular processes, such as cell division. A zinc deficiency can lead to problems with the immune system, birth defects, and blindness. This problem is especially important to address in developing countries where nutrition is limited. Supplements can be taken to increase the zinc intake, however it is difficult to determine who is zinc deficient and requires these supplements. The gold standard tests for determining the zinc concentration in the human body are both expensive and time-consuming. Zinc in human fingernails can be shown to represent the overall zinc concentration in the body. Laser-induced breakdown spectroscopy (LIBS) provides a quick analysis of the zinc concentration in a human fingernail with minimal sample preparation, thus LIBS could serve as a real-time biomedical assay for zinc deficiency. LIBS was performed on a collection of healthy human finger nails in an argon environment. The intensities of the zinc ion lines observed in the plasma were proportional to the zinc concentrations of each nail as measured by SIDMS. The variance of the measured zinc intensities between fingers of a given hand and between left and right hands for a single person was studied. Normalization of the zinc lines to other emission lines in the spectrum to reduce shot to shot variation was investigated. Studies were also performed to determine the spatial distribution of zinc within the nail. The influence of nail preparation prior to LIBS testing is an ongoing area of study.
        Speaker: Ms Vlora Riberdy (University of Windsor)
        Slides
      • 87
        The 2018 Shutdown of the NRU Reactor
        The federal government recently announced its decision to shut down the NRU reactor in 2018. The National Research Universal (NRU) reactor commenced operation in 1957, to provide neutrons for several missions simultaneously, including the production of neutron beams to support fundamental experimental research on solids and liquids, advancing knowledge of condensed matter physics. Today, the Canadian Neutron Beam Centre manages six thermal neutron beam lines at the NRU reactor, and sustains a team of scientific and technical experts who enable collaborative research projects to be performed effectively by students and scientists from over 30 Canadian universities, as well as over 100 foreign institutions from about 20 countries. The Canadian Institute for Neutron Scattering has organized a meeting for Canada’s physics community to consider whether and how the imminent loss of this unique Canadian resource should be addressed. This presentation will provide historical context and details of the current situation, as background for an informed conversation about options and actions over the next few years.
        Speaker: Dr John Root (Canadian Neutron Beam Centre)
    • M1-6 Neutrinoless Double-beta Decay I (PPD-DNP) / Double désintégration beta sans neutrino I (PPD-DPN) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: Rudiger Picker (TRIUMF)
      • 88
        Neutrino in the Standard Model and beyond
        The Standard Model teaches us that in the framework of such general principles as local gauge symmetry, unication of weak and electromag- netic interactions and Brout-Englert-Higgs spontaneous breaking of the elec- troweak symmetry nature chooses the simplest possibilities. Two-component left-handed massless neutrino elds play crucial role in the determination of the charged current structure of the Standard Model. The absence of the right-handed neutrino elds in the Standard Model is the simplest, most economical possibility. In such a scenario Majorana mass term is the only possibility for neutrinos to be massive and mixed. Such mass term is gener- ated by the lepton-number violating Weinberg eective Lagrangian. In this approach three Majorana neutrino masses are suppressed with respect to the masses of other fundamental fermions by the ratio of the electroweak scale and a scale of a lepton-number violating physics. The discovery of the neu- trinoless double -decay and absence of transitions of avor neutrinos into sterile states would be evidence in favor of the minimal scenario we advocate here. 1
        Speaker: Prof. Samoil Bilenky (JINR (Dubna))
      • 89
        Status of the SNO+ Experiment
        The SNO+ experiment, at the SNOLAB underground laboratory, consists of 780 Mg of linear alkylbenzene scintillator contained in the 12 m diameter SNO acrylic sphere and and observed by the SNO photomultiplier tubes. SNO+ will be loaded with tellurium, at approximately the 0.3% level to enable a sensitive search for neutrinoless double beta decay. This talk will detail the experiment, the sensitivity and the status of the detector.
        Speaker: Prof. Aksel Hallin (University of Alberta)
        Slides
      • 90
        Extraction of optical parameters in SNO+ with an in-situ optical calibration system
        SNO+ is a multi-purpose neutrino physics experiment investigating neutrinoless double beta decay and neutrino oscillations. The SNO+ detector consists of a 12m diameter acrylic vessel (AV), surrounded by ultra-pure water and approximately 9500 photomultiplier tubes (PMTs) which are positioned on a stainless steel PMT support structure (PSUP). The acrylic vessel will be filled with liquid scintillator. An in-situ optical calibration system based on LEDs and laser sources has been deployed. These optical sources feed light into the detector via optical fibres mounted on the PSUP, resulting in various beams of light. A collimated source will be used to measure the scattering in the liquid scintillator. Data have been taken while the AV was empty to understand the optical properties of the detector. We have analyzed the data to establish properties of the calibration system and to quantify the surface parameters, reflectivity and surface roughness responsible for scattering, as well as various parameters of the optical calibration system. These parameters will be a valuable input to the position and energy reconstruction algorithms, as well as the simulation, of SNO+.
        Speaker: Dr Kalpana Singh Singh (Department of Physics, University of Alberta)
        Slides
      • 91
        Double-beta decay half-life of 96Zr – nuclear physics meets geochemistry
        Double-beta (\beta\beta) decay measurements are a class of nuclear studies with the objective of detecting the neutrinoless (0\nu) decay variants. Detection of a 0\nu\beta\beta decay would prove the neutrino to be massive and to be its own anti-particle (i.e., a Majorana particle). A key parameter in the detection of the 0\nu\beta\beta decay is the energy, or Q-value, of the decay. ^{96}Zr is of particular interest as a double-beta decay candidate. A geochemical measurement of its \beta\beta decay half-life by measuring an isotopic anomaly of the ^{96}Mo daughter in ancient zircon samples yielded a value of 0.94(32)x10^{19} yr [1]. More recently, the NEMO collaboration measured the half-life directly to be 2.4(3)x10^{19} yr [2], twice as long as the geochemical measurement. As the geochemical result could be contaminated by a sequence of two single \beta-decays, the first being a 4-fold unique forbidden \beta-decay of ^{96}Zr to the 44 keV J^{\pi}=5^+ excited state in ^{96}Nb, followed by the 23 h \beta-decay of ^{96}Nb to ^{96}Mo, further study is mandated. Depending on the Q-value for the first decay, the estimated half-life could be of the same order as the one for the \beta\beta-decay [3]. However, the key parameter is the Q-value for the single \beta-decay, which enters in leading order as Q^{13} into the phase-space factor of the decay. Such a study is being carried out at the TRIUMF TITAN experiment and at the University of Calgary Isotope Science Lab. At TITAN we are measuring the Q-values for the ^{96}Zr to ^{96}Mo \beta\beta-decay and for the ^{96}Zr to ^{96}Nb single \beta-decay, with the goal of reaching a precision near 0.1 keV. At the UCalgary ISL, we are repeating the measurement of the ^{96}Mo isotopic anomaly using modern equipment and techniques. Combined, these measurements will remove a long-standing discrepancy of the two independent ^{96}Zr \beta\beta-decay half-life measurements. [1] M. E. Wieser and J. R. De Laeter, Phys. Rev. C 64, 024308 (2001). [2] NEMO-3 Collaboration, Nucl. Phys. A 847, 168-179 (2010). [3] J. Suhonen, Univ. Jyväskylä, private communication.
        Speaker: Adam Mayer (University of Calgary)
        Slides
    • M1-7 Advances in Nuclear Physics and Particle Physics Theory (DNP-PPD-DTP) / Progrès en physique nucléaire et en physique des particules théoriques (DPN-PPD-DPT) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Pierre Ouimet (University of Regina)
      • 92
        Ab initio calculations of nuclear structure and reactions
        The description of nuclei starting from the constituent nucleons and the realistic interactions among them has been a long-standing goal in nuclear physics. In recent years, a significant progress has been made in developing ab initio many-body approaches capable of describing both bound and scattering states in light and medium mass nuclei based on input from QCD employing Hamiltonians constructed within chiral effective field theory. We will discuss recent breakthroughs that allow for ab initio calculations for ground states, spectroscopy and reactions of nuclei and even hypernuclei throughout the p- and sd-shell and beyond with two- and three-nucleon interactions. We will also present results for nuclear reactions important for astrophysics, such as 7Be(p,γ)8B and 3He(α,γ)7Be radiative capture, and for 3H(d,n)4He fusion.
        Speaker: Petr Navratil (TRIUMF)
        Slides
      • 93
        New horizons for MCAS: heavier masses and alpha-particle scattering.
        The Multi-Channel Algebraic-Scattering (MCAS) method, developed in 2003 for the analysis of low-energy nuclear spectra and of resonant scattering, continues to be effectively used for nuclear-structure studies. The MCAS approach allows the construction of the nucleon-core model Hamiltonian which can be defined in detail (coupling to the collective modes, rotational or vibrational, diverse components of the interaction operators, nonlocal effects due to Pauli exclusion). As reported at previous CAP congresses, MCAS analyses have given good descriptions of bound states and low-lying resonant spectra of medium-light nuclei, including nuclei well off the line of stability. This presentation deals with new directions for MCAS, specifically, moving to heavier target nuclei (mass A = 18-23) and new projectiles in the scattering process, recently, the α particle. New results will be shown for n+18O and p+18O, n+22Ne, and α scattering on targets from mass A=3 to A=16, the last of these yielding structure information for 20Ne.
        Speaker: Dr Juris P. Svenne (University of Manitoba, Dept. of Physics and Astronomy)
        Slides
      • 94
        The coefficient of restitution of inflatable balls
        The bouncing of sports balls is often characterized in terms of the coefficient of restitution, which represents the ratio of the after-impact velocity to the before-impact velocity. While the behaviour of the coefficient of restitution as a function of the internal pressure of the ball has been studied, no theoretical justification has been given for any parametric curve fitted to the data. In this talk, we present a mechanistic model of the ball, leading to a simple two-parameter fit. The model will be compared to several commonly available sports balls.
        Speaker: Mr Gaëtan Landry (Dalhousie University)
        Slides
    • M1-8 Energy frontier: Standard Model and Higgs Boson I (PPD) / Frontière d'énergie: modèle standard et boson de Higgs I (PPD) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Bhubanjyoti Bhattacharya (University of Montreal)
      • 95
        Summary of ATLAS Standard Model measurements (including top quark)
        While the LHC is ramping up for it's second run at yet higher centre-of-mass energy, the experimental Collaborations are not only preparing for this run, but also ensuring that the maximum amount of information is extracted from the data taken in 2011 and 2012 at a centre-of-mass energy of 7 and 8 TeV, respectively. Many precision standard model measurements have been carried out, spanning some 14 orders of magnitude in production cross section. Some striking examples of achievements by the ATLAS Collaboration in measurements of production and properties of standard model particles will be presented. Particular focus will be placed on the observation of new processes or novel experimental techniques used to improve the precision of the analyses.
        Speaker: Alison Lister (University of British Columbia (CA))
        Slides
      • 96
        Measurement of the Higgs-boson properties with the ATLAS detector at the LHC
        A detailed review on the properties of the Higgs boson, as measured with the ATLAS experiment at the LHC, will be given. The results shown here use approximately 25 fb-1 of pp collision data, collected at 7 TeV and 8 TeV in 2011 and 2012. The measurements of the mass, couplings properties and main quantum numbers will be presented. Prospects for the upcoming Run2, starting in May 2015, will be reviewed.
        Speaker: Manuela Venturi (University of Victoria (CA))
        Slides
      • 97
        Measurement of the yy -> WW cross-section and searches for anomalous quartic gauge couplings WWAA at the ATLAS experiment
        Searches for the anomalous quartic gauge coupling of two photons to two W bosons (WWAA) were made at LEP and Tevatron. More recently many searches have been performed by the CMS and ATLAS collaborations at the Large Hadron Collider (LHC). Among the processes sensitive to these couplings are the Wy and yy -> WW production. In hadron colliders, yy -> WW events where the W bosons decay into leptons (electrons, muons or taus that subsequently transform into electrons or muons) have a clean signature. The two charged leptons originate from a vertex devoid of other outgoing particles, because they are produced by an electroweak interaction. Isolating the lepton vertex from other tracks suppresses strong interactions that produce many extra charged particles including higher cross-section processes such as Drell-Yan and top production. In this talk, I will present the measurement of the yy -> WW cross-section and searches for the WWAA anomalous quartic gauge couplings using the data collected by the ATLAS experiment during 2012.
        Speaker: Chav Chhiv Chau (University of Toronto (CA))
        Slides
    • M1-9 Ultrafast and Time-resolved Processes (DAMOPC) / (DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Chitra Rangan (University of Windsor)
      • 98
        Following an Auger Decay by Attosecond Pump-Probe Measurements
        Attosecond Physics is an emerging field at the international level which now provides tabletop attosecond (as=10^-18 s.) light sources extending from the extreme ultraviolet (XUV, 10-100 eV) to X-rays (keV) [1]. This feat opens new avenues in atomic and molecular spectroscopies [2], especially, to perform time-resolved experiments of ultrafast electron dynamics on the unexplored attosecond timescale [3]. I will present the first attosecond pump-probe measurement where an XUV attosecond pulse initiates an Auger decay and where an attosecond broadband optical pulse probes this ultrafast process. Supported by our model, we suggest that the optical probe acts as a gate of the Auger transition, in analogy with the FROG (frequency-resolved optical gating) technique commonly-used for measuring femtosecond laser pulses [4]. We believe this is a universal idea that will prevail in attosecond measurements [5]: I will show how our pump-probe scheme and modeling can reveal few-femtoseconds (atomic) to sub-fs (condensed matter) Auger lifetimes. [1] T. Popmintchev *et al.*, Nature Photonics 4, 822 (2010). [2] J. B. Bertrand *et al.*, Nature Physics 9, 174 (2013). [3] S. R. Leone *et al.*, Nature Photonics 8, 162 (2014). [4] R. Trebino, FROG, Kluwer Academic Publishers, Boston (2002). [5] A. Moulet, J.B. Bertrand *et al.*, Okinawa, Ultrafast Phenomena (2014).
        Speaker: Prof. Julien Beaudoin Bertrand (Université Laval)
      • 99
        Ultrafast imaging of nonlinear terahertz pulse transmission in semiconductors
        Terahertz pulse spectroscopy has been widely used for probing the optical properties and ultrafast carrier dynamics of materials in the far-infrared region of the spectrum. Recently, sources of intense terahertz (THz) pulses with peak fields higher than 100 kV/cm have allowed researchers to explore ultrafast nonlinear THz dynamics in materials, such as THz-pulse-induced intervalley scattering in semiconductors. Here, we use a gated intensified CCD camera and full-field electro-optic imaging with femtosecond laser pulses to directly observe dipole electric fields arising from shift currents induced by intense THz pulses in n-doped InGaAs. Voltage pulses generated by the THz-pulse-induced shift currents are also measured directly on a high speed oscilloscope. The polarization of the shift current with respect to that of the THz pump beam is determined. The simultaneous measurement of both the induced dipole and transmitted THz pulse allows for sub-picosecond resolution imaging of nonlinear THz dynamics in semiconductors.
        Speaker: Haille Sharum (University of Alberta)
      • 100
        Energy transfer dynamics in blue emitting functionalized silicon nanocrystals
        We use time-resolved photoluminescence (TRPL) spectroscopy to study the effects of surface passivation and nanocrystal (NC) size on the ultrafast PL dynamics of colloidal SiNCs. The SiNCs were passivated by dodecylamine and ammonia, and exhibit blue emission centered at ~473 nm and ~495 nm, respectively. For both functionalizations, increasing the size of the NCs from ~3 nm to ~6 nm did not result in a PL red-shift, but instead show an identical spectral profile. More interestingly, the nanosecond PL decay dynamics are size- and wavelength-independent with a radiative recombination rate on the order of ~108/s, characteristic of PL from charge transfer states associated with silicon oxynitride bond. Based on TRPL and fluence-dependent measurements, we hypothesize that electrons are first photoexcited within the SiNCs and then rapidly transferred to silicon oxynitride bonds at the surface, creating charge transfer states responsible for the nanosecond blue PL.
        Speaker: Glenda De los Reyes (Physics Department, University of Alberta)
      • 101
        Molecular SuperRotors: Control and properties of molecules in extreme rotational states
        Extremely fast rotating molecules, known as “super-rotors”, may exhibit a number of unique properties, from rotation-induced nano-scale magnetism to formation of macroscopic gas vortices. Orchestrating molecular spinning in a broad range of angular frequencies is appealing from the perspectives of controlling molecular dynamics. Yet in sharp contrast to an optical excitation of molecular vibration, laser control of molecular rotation is rather challenging. I will report on our recent progress in generating and controlling molecular super-rotors (e.g. oxygen molecules occupying ultrahigh rotational states, J > 120, or carbon dioxide with J>400) with a specially designed intense laser pulses, known as an “optical centrifuge”. I will discuss the results of our study of collisional, optical and magnetic properties of molecular superrotors.
        Speaker: Valery Milner (UBC)
    • Health Break / Pause santé CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • CAP-NSERC Liaison Cttee Mtg / Réunion du comité de liaison ACP-CRSNG CCIS 4-285

      CCIS 4-285

      University of Alberta

      Convener: Bill Whelan (University of Prince Edward Island)
    • M2-1 Computational methods in condensed matter physics (DCMMP) / Méthodes numériques en physique de la matière condensée (DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Jesko Sirker (U Manitoba)
      • 102
        Extrinsic Spin Hall Effect in Graphene
        The intrinsic spin-orbit coupling in graphene is extremely weak, making it a promising spin conductor for spintronic devices. However, for many applications it is desirable to also be able to generate spin currents.Theoretical predictions and recent experimental results suggest one can engineer the spin Hall effect in graphene by greatly enhancing the spin-orbit coupling in the vicinity of an impurity. The extrinsic spin Hall effect then results from the spin-dependent scattering of carriers by impurities in the presence of spin-orbit interaction. This effect can be used to convert charge currents into spin currents efficiently. I will discuss recent experimental results on spin Hall effect in graphene decorated with adatoms and metallic clusters[1,2] and show that a large spin Hall effect can appear in graphene in the presence of locally enhanced spin-orbit coupling. I will present results from single impurity scattering calculations [3], and also from a real-space implementation of the Kubo formalism [4] for tight-binding Hamiltonians with different forms of spin-orbit coupling. [1] J. Balakrishnan et al., Nat. Phys. 9, 284 (2013). [2] J. Balakrishnan et al., Nat. Commun. 5, 4748 (2014). [3] A. Ferreira, T. G. Rappoport, M. A. Cazalilla, A. H. Castro Neto, Phys. Rev. Lett. 112, 066601 (2014). [4] Jose H. Garcia, Lucian Covaci and Tatiana G. Rappoport, arXiv:1410.8140.
        Speaker: Tatiana Rappoport (Federal University of Rio de Janeiro)
      • 103
        Klein Tunnelling in Graphene
        In 1929 Oskar Klein solved the Dirac equation for electrons scattering off of a barrier. He found that the transmission probability increased with potential height unlike the non-relativistic case where it decreases exponentially. This phenomenon can also been in a graphene lattice where the energy bands form a structure known as a Dirac cone around the points where they touch. In this project we analyze phenomenon without substituting the graphene hamiltonian for the Dirac hamiltonian. First we analyse the propagation of gaussian wave packets on the one dimensional lattice, the two dimensional square lattice, and the graphene lattice. Here we look at how the wave packet evolves in time as it propagates. We then study how the packet tunnels through barriers on the graphene lattice, focusing on the region where the Dirac cone is formed We compare this tunnelling to the case of the non-relativistic and the relativistic free particle.
        Speaker: Mr Kameron Palmer (University of Alberta)
      • 104
        Extensions of Kinetic Monte Carlo simulations to study thermally activated grain reversal in dual-layer Exchange Coupled Composite recording media.
        Thermal activation processes represent the biggest challenge to maintain data on magnetic recording media, which is composed of uniformly magnetized nano-meter grains. These processes occur over long time scales, years or decades, and result in reversing magnetization of the media grains by rare events. Typically, rare events present a challenge if modelled by conventional micromagnetic techniques as they are limited to time scales on the order of microseconds even with the best computer resources. A convenient approach that can access long time scales and be able to simulate such rare events processes is the Kinetic Monte Carlo method (KMC). The KMC method computes the time between successive grain reversals induced by an external magnetic field based on an Arrhenius-Neel approximation for thermally activated processes. The KMC method has recently been applied to model single-layer media [1], and we have now extended the method to study dual-layer Exchange Coupled Composition (ECC) media used in current generations of disc drives. A complication to using the KMC method for ECC media is governed by the complex reversal process of coupled grains due to the existence of metastable states. The energy barrier separating the metastable states is obtained from the minimum energy path (MEP) using a variant of the nudged elastic band method [2] and the attempt frequency is calculated based on the Langer formalism [3]. To simplify carrying KMC from single layer media to a dual-layer, we have performed a detailed study for only two coupled grains to help us understand and explore the energy landscape of ECC media and be able to handle the complications associated with ECC media [4]. Applications to study characteristic MH hysteresis loops for multi-grained dual-layered systems is made. 1. M. L. Plumer, T. J. Fal, J. I. Mercer, J. P. Whitehead, J. van Ek, and A. Ajan, IEEE Trans. Mag, 50, 3100805 (2014). 2. R. Dittrich, T. Schrefl, D. Suess, W. Scholz, H. Forster and J. Fidler, R. J.M.M.M. 250, L12–L19 (2002). 3. J. S. Langer, Ann. Phys. 54 258, N.Y. (1969). 4. A. M. Almudallal, J. I. Mercer, J. P. Whitehead, M. Plumer, J. van Ek and T. J. Fal (submitted).
        Speaker: Dr Ahmad Almudallal (Memorial University of Newfoundland)
      • 105
        The Kronig-Penney model extended to arbitrary potentials via numerical matrix mechanics
        We present a general method using matrix mechanics to calculate the bandstructure for 1D periodic potential arrays, filling in a pedagogical gap between the analytic solutions to the Kronig-Penney model and more complicated methods like tight-binding. By embedding the potential for a unit cell of the array in a region with periodic boundary conditions, we can expand in complex exponential basis states to solve for the matrix elements. We show that Bloch's condition can be added in a potential-independent way, and so repeated diagonalizations of the unit cell matrix with different parameters of the crystal momentum will fill out the bandstructure. Comparisons with the analytic solutions to the Kronig-Penney model show excellent agreement. We then generate bands for two variants of the Kronig-Penney model, the periodic harmonic oscillator and its inverted form, and a symmetric linear well such that each has similarly-bounded electrons at the peak of the third energy band. We show how these different, more "realistic", potentials can be used to tune electron-hole effective mass asymmetries. Finally, preliminary results for the extension to 2D are demonstrated.
        Speaker: Mr Pavelich Robert (University of Alberta)
        Slides
      • 106
        A Multiorbital DMFT Analysis of Electron-Hole Asymmetry in the Dynamic Hubbard Model
        The dynamic Hubbard model (DHM) improves on the description of strongly correlated electron systems provided by the conventional single-band Hubbard model through additional electronic degrees of freedom, namely a second, higher energy orbital and associated hybridization parameters for interorbital transitions. The additional orbital in the DHM provides a more realistic modeling of electronic orbital "relaxation" in real lattices. One result of orbital relaxation is a clear electron-hole asymmetry, absent in the single-band case. We have employed the computational technique of dynamical mean field theory, generalized to the two-orbital case, to study this asymmetry with respect to varying system parameters, including both intersite and intrasite orbital hybridization as well as the role played by Mott physics. Our results stand in good agreement with previous exact diagonalization studies of the DHM.
        Speaker: Christopher Polachic
        Slides
    • M2-10 Atomic and Molecular Spectroscopy: microwave to X-ray (DAMOPC) / Spectroscopie atomique et moléculaire: des micro-ondes aux rayons X (DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Steven Rehse (University of Windsor)
      • 107
        SPECTROSCOPIC LINE-SHAPE STUDIES FOR ENVIRONMENTAL AND METROLOGIC APPLICATIONS
        Our research group has investigated the spectra of several gases of environmental importance using our 3-channel laser spectrometer or the experimental facility at the far-infrared beamline at the Canadian Light Source. Our results have been used by others through our contributions to the HITRAN and GEISA databases used by the atmospheric community and we have made our own contributions to the field. Our group has also performed accurate measurements of the fundamental Boltzmann constant based on a line-shape analysis of acetylene spectra recorded using a tunable diode laser. This study is of high importance since the accuracy of our laser spectroscopy based measurement is the second best in the world.
        Speakers: Li-Hong Xu (University of New Brunswick), Ronald Lees (University of New Brunswick)
        Paper
        Slides
      • 108
        CLS Synchrotron FIR Spectroscopy of High Torsional Levels of CD3OH: The Tau of Methanol
        Structure from high torsional levels of the CD$_3$OH isotopologue of methanol has been analyzed in Fourier transform spectra recorded at the Far-Infrared beamline of the Canadian Light Source synchrotron in Saskatoon. Energy term values for $A$ and $E$ torsional species of the third excited torsional state, v$_t$ = 3, are now almost complete up to rotational levels $K$ = 15, and thirteen substates have so far been identified for v$_t$ = 4. The spectra show interesting close groupings of strong high-v$_t$ sub-bands related by Dennison’s torsional symmetry index $/tau$, rather than $A$ and $E$, that can be understood in terms of a simple and universal free-rotor “spectral predictor” chart. The energy curves for the v$_t$ = 3 and 4 ground-state torsional levels pass through several of the excited vibrational states, and a number of anharmonic and Coriolis interactions have been detected through perturbations to the spectra and appearance of forbidden sub-bands due to strong mixing and intensity borrowing.
        Speaker: Dr Ronald Lees (Centre for Laser, Atomic and Molecular Sciences, Department of Physics, University of NB)
        Slides
      • 109
        Analysis of Quantum Defects in high energy Helium P states
        Quantum defects are useful in interpreting high energy atomic states in terms of simple Hydrogenic energy levels. We will find the energy levels for 1snp singlet and triplet P state Helium from $n = 2$ to $n = 12$ with some of the most accurate helium atom calculations to date using the exact non-relativistic Hamiltonian with wave functions expanded in a basis set of Hylleraas coordinates. The results will be used to determine accurate values for the coefficients in the quantum defect expansion: $\delta = \delta_0 + \delta_2/n^{*2} + \delta_4/n^{*4} + \cdots$, where $n^* = n - \delta$. We will also test the usual assumption that only the even powers of $1/n^*$ need be included [1]. In addition, we will study the effectiveness of a unitary transformation in reducing the numerical linear dependence of the basis set for large basis sets.
        Speaker: Ryan Peck
      • 110
        Precision Measurement of Lithium Hyperfine and Fine Structure Intervals
        A number of experiments have precisely measured fine and hyperfine structure splittings as well as isotope shifts for several transitions at optical frequencies for 6,7Li [1]. These data offer an important test of theoretical techniques developed by two groups to accurately calculate effects due to QED and the finite nuclear size in 2 and 3 electron atoms. The work by multiple groups studying several transitions in both Li+ and neutral Li permits a critical examination of the consistency of separately the experimental work as well as theory. Combining the measured isotope shifts with the calculated energy shifts passing these consistency tests permits the determination of the relative nuclear charge radius with an uncertainty approaching 1 x 10-18 meter which is more than an order of magnitude better than obtained by electron scattering. Progress toward a precision measurement of the fine structure constant is also discussed. 1. W. A. van Wijngaarden & B. Jian, European Physical Journal D, 222, 2057-2066 (2013)
        Speaker: Prof. William van Wijngaarden (Physics Department, York University)
        Slides
      • 111
        Dual Co-Magnetometer using Xe129 for Measurement of the
 Neutron’s Electron Dipole Moment
        A new high-density ultra cold neutron source is being constructed and developed at TRIUMF in Vancouver, BC with collaborators from Japan and several Canada research groups. One of the first goals of this collaboration is to measure the electric dipole moment (EDM) of the neutron to an uncertainty of <10$^{-27}$ e-cm. To measure the nEDM, a magnetic resonance (MR) experiment on polarized neutrons is performed and the uncertainty of these measurements is limited by how well the magnetic field surrounding the neutrons is known. Previous nEDM experiments relied on a precise in-situ measurement of the homogeneous magnetic field using a Ramsey fringe measurement of the spin precession of Hg$^{199}$ (co-habituating with the cold neutrons). Our efforts are to develop a co-magnetometer for nEDM measurements in which both Hg$^{199}$ and a second atomic species (Xe$^{129}$) are introduced into the same region as the neutrons and measured simultaneously to better characterize the geometric phase effects which dominate the systematic uncertainties in the magnetic field determination. Xe$^{129}$ was chosen, in part, due to its negligible interactions with the neutrons and the Hg$^{199}$. The spin precession of Xe$^{129}$will be detected by measuring the fluorescence decay following a spin-selective 2-photon transition (driven by 252 nm light) from the ground 5p$^6$($^1$S0) state to the 5p$^5$($^2$P$_{3/2}$)6p excited state. For this purpose, we have first developed a high power (~200 mW) continuous wave UV laser. In this talk we will discuss the next steps in our co- magnetometer development: our latest results on characterizing the precision of Xe$^{129}$in the excited state using this laser and subsequently measuring the Larmor frequency of the polarized Xe$^{129}$ in a magnetic field.
        Speaker: Joshua Wienands (University of British Columbia)
    • M2-2 Material growth and processing (DCMMP) / Croissance et traitement des matériaux (DPMCM) CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: David Broun (Simon Fraser University)
      • 112
        Field-tuned quantum criticality of heavy fermion systems
        Intensive study of strongly correlated electronic systems has revealed the existence of quantum phase transitions from ordered states to disordered states driven by non-thermal control parameters such as chemical doping, pressure, and magnetic field. In this presentation I will discuss a recent progress of magnetic field-tuned quantum criticality with particular emphasis on the Fermi liquid instabilities of conduction electrons in heavy fermion metals and emergent phases around quantum critical points. In particular, a wide range of strange metallic behavior has been observed beyond the quantum critical point in Yb-based materials; YbAgGe, Ge-doped YbRh2Si2, YbPtBi. In the H-T phase diagram of YbPtBi, for example, three regimes of its low temperature states emerges: (I) antiferromagnetic state, characterized by spin density wave like feature, which can be suppressed to T = 0 by the relatively small magnetic field of Hc ~ 4 kOe, (II) field induced anomalous state in which the electrical resistivity follows r(T) ~ T1.5 between Hc and ~ 8 kOe, and (III) Fermi liquid state in which r(T) ~ T2 for H > 8 kOe. Regions I and II are separated at T = 0 by what appears to be a quantum critical point. Whereas region III appears to be a Fermi liquid associated with the hybridized 4f states of Yb, region II may be a manifestation of a spin liquid state. The observation of a separation between the antiferromagnetic phase boundary and the small to large Fermi surface transition in recent experiments has led to the new perspective on the mechanism for quantum criticality. In this new approach, the global phase diagram includes the effects of magnetic frustration, which is an important additional tuning parameter in the Kondo lattice model of heavy fermion materials. Frustration leads to the enhanced quantum fluctuations, as the system tunnels between different competing magnetic states.
        Speaker: Prof. Eundeok Mun (Simon Fraser University)
      • 113
        Ge:Mn Dilute Magnetic Semiconductor
        This work aims to develop Ge:Mn dilute magnetic semiconductor and study the fundamental origin of ferromagnetism in this system. Using ion implantation at $77$ K, a single crystal Ge wafer was doped with magnetic Mn ions. The implantation was done at ion energy of $4.76$ MeV with a fluence of 2 x 10$^{16}$ ion/cm$^2$. X-ray diffraction (XRD) of the as-implanted sample showed that the implanted layer was amorphous. Therefore, different samples were annealed at $200$⁰C, $330$⁰C and $600$⁰C in a tube furnace to achieve a solid phase epitaxial regrowth of the implanted layer. XRD of the sample annealed at $330$⁰C for $33$ hours showed a polycrystalline layer. The depth profile of Mn in the as-implanted sample and the post-annealed sample at $330$⁰C was determined using secondary ion mass spectroscopy (SIMS) and it was found that some Mn diffused to the surface during the annealing. XRD of the sample annealed at $600$⁰C for $35$ minute showed peaks corresponding to an unknown phase in addition to peaks from amorphous and polycrystalline Ge. The sample annealed at $200$⁰C for $168$ hour showed no evidence of solid phase epitaxy. A SQUID was used to measure the magnetic properties of all samples. At low temperature, the as-implanted sample showed a paramagnetic behaviour. A magnetic hysteresis at $5$K and up to $200$K was observed for the samples annealed at $330$⁰C and $200$⁰C. The $600$⁰C annealed sample showed no ferromagnetic response and a significant reduction in the paramagnetic response at low temperature compared to the as-implanted sample.
        Speaker: Laila Obied (Brock University)
      • 114
        The nanostructure of (Ybx, Y1-x)2O3 thin films obtained by reactive crossed-beam laser ablation using bright-field and high-angle annular dark-field STEM imaging.
        Ytterbium-doped yttrium oxide thin films were obtained with a variant of pulsed laser deposition, called reactive crossed-beam laser deposition, wherein a cross-flow of oxygen, synchronized with the laser pulses, is used for oxidizing and entraining the ablation products of a Yb/Y alloy target towards a substrate placed inside a vacuum chamber [1]. The nanostructure of the films is examined using X-ray and electron diffraction, as well as Scanning Transmission Electron Microscopy (STEM). As-produced coatings are amorphous and become nanocrystalline cubic yttria after annealing. STEM images taken in the Bright-Field and in the High-Angle Annular Dark-Field modes reveal complementary aspects of the nanostructure of yttria, namely the presence of oxygen vacancies as well as distortion of the cationic lattice respectively. These peculiarities of the crystalline structure play an important role in the luminescence properties of the Yb3+ ions, since they lower the crystal-field symmetry of the Yb3+ substitution site, which directly affect the luminescence spectra. Thin films made of luminescent materials are attractive for many applications such as coherent miniature optical sources [2], optical converter from the infrared to the visible range for in-vivo imaging [3], to name a few. Des revêtements d’oxyde d’ytterbium et d’yttrium (YbxY1-x)2O3 nanostructurés ont été déposés à l’aide d’une variante de l’ablation laser, pour laquelle le transport et l’oxydation des produits d’ablation d’une cible métallique vers le substrat se font à l’aide de courtes bouffées d’oxygène synchronisées avec le laser [1]. La nanostructure et les propriétés de luminescence de nos revêtements ont été étudiées par diffraction aux rayons X et diffraction électronique ainsi que par microscopie électronique à transmission. Les dépôts obtenus sont amorphes et deviennent nanocristallins après recuit. Pour la première fois à notre connaissance, nous avons mis en évidence, en tirant profit de la complémentarité des images obtenues par microscopie électronique à transmission en champ sombre et en champ clair, la présence de lacunes d’oxygènes et la distorsion du réseau cationique. Ces deux particularités jouent un rôle important dans les propriétés de luminescence des ions d’Yb3+ puisqu’elles permettent l’apparition de sites de substitution à faible symétrie, augmentant ainsi la probabilité de relaxation radiative de l’ion excité. La capacité de contrôler la taille des nanocristaux par un recuit permet de contrôler la forme du spectre de luminescence. Les matériaux luminescents déposés sous forme de couches minces sont très attrayants pour plusieurs applications comme les sources lumineuses cohérentes miniaturisées [2], la conversion dans domaine du visible pour l’imagerie ou la détection in-vivo [3], etc. References : [1] J.-F Bisson, G. Patriarche, T. Marest, J. Thibodeau, (2015) Nanostructure and luminescence properties of amorphous and crystalline ytterbium-yttrium oxide thin films obtained with pulsed reactive crossed-beam deposition, J. Mater. Sci., 50(3), 1267-1276 [2] I C Robin, R Kumaran, S Penson, S E Webster, T Tiedje and A Oleinik (2008) Structure and photoluminescence of Nd:Y2O3 grown by molecular beam epitaxy. Opt. Mat. 30: 835-838 [3] G S Yi, G M Chow, Synthesis of hexagonal-phase NaYF4 : Yb,Er and NaYF4 : Yb,Tm nanocrystals with efficient up-conversion fluorescence (2006) Adv. Funct. Mater. 16(18), 2324-2329
        Speaker: Prof. Jean-François Bisson (Université de Moncton)
        Slides
      • 115
        Investigation of the effect of growth condition on defects in MBE grown GaAs1-xBix
        Incorporation of Bismuth into GaAs causes an anomalous bandgap reduction (88 meV/% for dilute alloys) with rather small lattice mismatch compared to ternary In or Sb alloys. The bandgap can be adjusted over a wide range of infrared wavelengths up to 2.5 μm by controlling the Bi content of the alloy which is useful for laser, detector and solar cell applications. Semiconductor lasers are compact and efficient so they are the preferable choice in many applications. GaAs1-xBix can be used as the light emitting material for the 1-1.3 μm communication wavelengths. Another application is vertical-external-cavity surface-emitting- lasers (VECSEL) to generate high power infrared output and then doubling the frequency to achieve yellow laser light. The first step to make a laser is optimizing GaAs1-xBix growth parameters to realize the best material quality which cannot be achieved unless the defects in the crystal are understood. The three requirements for MBE growth of GaAs1-xBix are: low growth temperature (compared to standard GaAs), small As2:Ga ratio and controlled Bi flux. In this research, we tried to understand the relation between the growth conditions and the crystal defects using photoluminescence (PL) and deep level transient spectroscopy (DLTS). PL intensity is a good relative gauge for the number of defects as the defects are typically non-radiative recombination centres. Our results show that the reduction of growth temperature from 400°C to 300°C with all other growth conditions fixed causes the Bi concentration in the deposited films to increase from 1% to 5% but the PL intensity decreases by more than a factor of 1000. Changes in the other two growth conditions, As2:Ga ratio and Bi flux, affect the Bi incorporation but they are not as important factors in the PL intensity as the growth temperature. Two samples were grown at different temperatures (330°C and 375°C) with approximately the same Bi concentration (~2%) at a stoichiometric As:Ga flux ratio. The temperature dependence of the PL shows that the sample grown at higher temperature has less photoluminescence emission from shallow defect states and a stronger temperature dependence of the bandgap. We interpret the shallow defects as intrinsic localized states close to the valence band edge associated with Bi next nearest neighbour clusters. DLTS measurements on GaAs and GaAsBi samples show that the density of deep levels increases at low growth temperature and that a Bi surfactant reduces the density of deep levels. DLTS measurements on dilute GaAsBi samples grown at different temperatures will be presented.
        Speaker: Vahid Bahrami Yekta (University of Victoria)
      • 116
        Atomic Force Microscopy Characterization of Hydrogen Terminated Silicon (100) 2x1 Reconstruction
        Hydrogen terminated silicon (100) $2 \times 1$ (H:Si(100)) is examined using a novel non-contact atomic force microscopy (NC-AFM) approach. NC-AFM gives access to unique information on the surface such as unperturbed surface charge distributions, chemical bonding, and surface forces. H:Si(100) is an attractive surface for examination due to its potential for nano-electronics. Dangling bonds on the surface act as atomic silicon quantum dots and have application in quantum dot cellular automata-based nano-computing, which through geometrical arrangement can be used to create ultra-fast, ultra-low-power wires and logic gates. It also provides a promising platform for AFM examination of electronically decoupled adsorbed atoms, physisorbed molecules, and chemisorbed molecular structures. As part of this AFM analysis of H:Si(100), images were taken in the as yet unexplored constant height scanning mode. By incrementing the tip-sample distance above the surface, different force regimes were accessed. Attractive van der Waals forces were observed in the long range, and repulsive interactions indicative of Pauli-repulsive forces were seen at close range. An evolution of surface topography from attractive to repulsive surface forces is demonstrated, with the repulsive regime showing the first direct observation of the chemical bond structure of H:Si(100). Furthermore, site-specific force spectroscopy on key surface lattice points reveals unique force contributions. These location-specific profiles are compared to Density Functional Theory modeling for the surface, with catalogued site-specific differences having application in subtraction of background forces for the aforementioned deposited molecule or atom examination. NC-AFM contributes strongly to our understanding of forces at play in the surface structure of H:Si(100), opening the way for many future experiments.
        Speaker: Ms Taleana Huff (University of Alberta)
    • M2-3 Theory, modelling and space weather II (DASP) / Théorie, modélisation et climat spatial II (DPAE) CAB 243

      CAB 243

      University of Alberta

      Convener: David Knudsen (University of Calgary)
      • 117
        Development of Comprehensive Model of Earth Ionosphere and its Application for Studies of MI-coupling
        A comprehensive model of the Earth ionosphere has been developed [Sydorenko and Rankin, 2012 and 2013]. The model is two-dimensional, it resolves the meridional direction and the direction along the geomagnetic field. The dipole coordinates are used, the azimuthal symmetry is assumed. The model considers torsional Alfven waves and includes the meridional convection electric field. The electric field along the geomagnetic field is calculated from the condition of quasineutrality. The ions (H+, N+, O+, N2+, NO+, and O2+) and the electrons are represented as conducting fluids. The neutrals (H, N, O, N2, NO, and O2) are considered as a stationary background, the meridional wind can be included but it does not change the neutral parameters. Numerous heating and cooling processes, chemical reactions between ions and neutrals, recombination, and effects of energetic electron precipitation and EUV radiation are included. The main simulation area covers the altitude range from 100 km to few thousand km, the width of the main area at the bottom is up to few hundred km. The model was applied to study oxygen ion upwelling caused by electron precipitation and Alfven waves. Recently, the model was used to investigate plasma density and temperature oscillation observed by EISCAT during the period of intense magnetospheric activity and predicted that the event was accompanied by significant modification of the composition of neutrals in the thermosphere. Sydorenko, D., and R. Rankin (2012), Simulation of ionospheric disturbances created by Alfvén waves, J. Geophys.Res., 117, A09229, doi:10.1029/2012JA017693. Sydorenko, D., and R. Rankin (2013), Simulation of O+ upflows created by electron precipitation and Alfvén waves in the ionosphere, J. Geophys. Res. Space Physics, 118, 5562–5578, doi:10.1002/jgra.50531.
        Speaker: Dr Dmytro Sydorenko (University of Alberta)
      • 118
        Solar wind modelling for operational forecasting
        Dark regions seen in extreme ultraviolet and X-ray images of the solar corona, called coronal holes (COHO), are known to be sources of fast solar wind streams. These streams often impact the Earth’s magnetosphere and produce geomagnetic storms to which Canada is susceptible. COHO are associated with open coronal magnetic field lines along which fast solar wind streams emanate from the Sun. COHO can survive several Sun’s rotations, especially near the solar minimum, giving rise to recurrent enhancements in the solar wind speed and geomagnetic activity. While solar wind forecasting can be based on COHO images by taking into account a statistical correlation between COHO area and solar wind parameters at the Earth, a more physics based approach considers open magnetic field lines that extend from the photosphere to the corona. To forecast the solar wind, a numerical code based on the coronal field approach has been developed. To derive the global coronal magnetic field a potential field source surface and Schatten current sheet models are used. Empirical relations, including Wang-Sheeley-Arge, are used to establish a link between the solar wind speed and properties of open magnetic field lines. Investigations of the solar wind speed and magnetic field polarity forecasts at the Earth for 2007-2014 show a good agreement with observations, most notably around solar minimum. Disagreements, excluding those due to transient solar disturbances, are discussed. In particular, the role of COHO area size, their latitudinal location and proximity to active regions is discussed. Prospects of using the solar wind forecast in forecasting geomagnetic activity over Canada are examined.
        Speaker: Ljubomir Nikolic (Natural Resources Canada)
      • 119
        Using an information theory-based method for statistical detection of high-frequency climate signals in northern-hemisphere water supply variations
        Water scarcity is an acute global concern under population and economic growth, and understanding hydroclimatic variation is becoming commensurately more important for resource management. Climatic drivers of water availability vary complexly on many time- and space-scales, but serendipitously, the climate system tends to self-organize into coherent dynamical modes. Two of these are El Niño-Southern Oscillation (ENSO) and the Arctic Oscillation (AO), which have hemisphere- to planet-wide impacts on regional climate through intricate relationships called teleconnections. Traditionally, statistical studies assume such teleconnections are linear, or at least monotonic. Recent work instead suggests ENSO and AO impacts can be strongly nonlinear – specifically, parabolic. However, these phenomena remain incompletely understood, and river flows spatiotemporally integrate upstream climatic influences in complicated ways, sensitive to local terrestrial hydrologic characteristics. We therefore directly examine annual flow volume time series from 42 of the northern hemisphere’s largest ocean-reaching rivers for highly nonlinear teleconnections. We apply a novel approach based on optimal polynomial selection using the Akaike information criterion, which combines the Kullback-Leibler information, quantifying how much information content is lost when approximating truth using a model, with maximum likelihood concepts. Unlike conventional null-hypothesis significance testing, the method provides a rigorously optimal balance between model performance and parsimony; explicitly accommodates no-effect, linear-effect, and strongly nonlinear-effect models; and estimates the probability that a model is true given the data. While we discover a rich diversity of responses, parabolic relationships are formally consistent with the data for almost half the rivers and are optimal for eight. Highly nonlinear teleconnections could radically alter the standard conceptual model of how water resources respond to climate variability. For example, the Sacramento River in drought-ridden California exhibits no significant linear ENSO teleconnection but a 92% probability of a quadratic relationship, improving simple mean predictive error by up to 65% and implying greater opportunity for climate-informed early-season water supply forecasting than previously appreciated.
        Speaker: Dr Sean W. Fleming (Environment Canada, MSC Science Division)
    • M2-4 Cosmic Frontier: Cosmology I (DTP-PPD-DIMP) / Frontière cosmique: cosmologie I (DPT-PPD-DPIM) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: James Pinfold (University of Alberta (CA))
      • 120
        Probing the Nature of Inflation
        The idea that the early universe included an era of accelerated expansion (Inflation) was proposed to explain very qualitative features of the first cosmological observations. Since then, our observations have improved dramatically and have lead to high precision agreement with the predictions of the first models of inflation, slow-roll inflation. At the same time, there has been significant growth in the number of mechanisms for inflation, many of which are qualitatively distinct from slow-roll. Nevertheless, most of these ideas are also consistent with current data. In this talk, I will review inflation and its current observational status. I will then discuss the important theoretical targets for the future and the prospects for achieving them.
        Speaker: Daniel Green
        Slides
      • 121
        Determining Power Spectra of High Energy Cosmics
        The angular power spectrum is a powerful observable for characterizing angular distributions, popularized by measurements of the cosmic microwave background (CMB). The power spectra of high energy cosmics ($\gamma$-rays, protons, neutrinos, etc.) contains information about their sources. Since these cosmics are observed on an event-by-event basis, the nature of the power spectrum measurement is fundamentally different from the CMB. We present new progress on the statistical properties of these power spectrum measurements and discuss the new information about the sources that can be gleaned from these observations.
        Speaker: Sheldon Campbell (The Ohio State University)
        Slides
      • 122
        Searching for the echoes of inflation from a balloon - The first SPIDER flight
        SPIDER is a balloon-borne polarimeter designed to detect B-modes in the CMB at degree angular scales. Such a signal is a characteristic of early universe gravitational waves, a cornerstone prediction of inflationary theory. Hanging from a balloon at an altitude of 36 km allows the instrument to bypass 99% of the atmosphere and get an unobstructed view of the sky at 90 and 150 GHz. The multi-band nature of the experiment will help characterize galactic foregrounds, which need to be well understood before a primordial polarization signal can be extracted from the data. During its first flight from Antarctica in January 2015, SPIDER probed 8% of the sky with 2000 polarization-sensitive bolometers. These were distributed amongst six cryogenically cooled telescopes housed in a 1300 liter liquid-helium cryostat. This massive cryostat was supported and steered by a light-weight carbon fibre structure, equipped with two sets of motors that controlled its pointing on the sky through real-time position feedback from a variety of sensors. I will discuss the performance of the instrument over the 16 day flight and what we might learn from the dataset. I will also give a glimpse into the capabilities of the upgraded instrument, scheduled to fly in 2018.
        Speaker: Ivan Padilla (University of Toronto)
        Slides
    • M2-5 Nuclear Astrophysics (DNP) / Astrophysique nucléaire (DPN) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Barry Davids (TRIUMF)
      • 123
        The turbulent hydrodynamics and nuclear astrophysics of anomalous stars from the early universe
        The anomalous abundances that can be found in the most metal-poor stars reflect the evidently large diversity of nuclear production sites in stars and stellar explosions, as well as the cosmological conditions for the formation and evolution of the first generations of stars. Significant progress in our predictive understanding of nuclear production in the early universe comes now within reach through advancing capabilities to perform large-scale 3D stellar hydrodynamic simulations of the violent outbursts of advanced nuclear burning. When complemented with comprehensive nucleosynthesis simulations we can characterize the chemical evolution of stellar populations. Nuclear production sites in the early universe involves unstable species on the p- and n-rich side of the valley of stability, and nuclear data in key cases is presently too uncertain to enable the required predictive simulation capability. These are the underpinnings to decipher the messages from the early universe hidden in the anomalous abundances of metal poor stars.
        Speaker: Falk Herwig (University of Victoria)
      • 124
        Quark-Novae : Implications to High-Energy and Nuclear Astrophysics
        After a brief account of the physics of the Quark-Nova (explosive transition of a neutron star to a quark star), I will discuss its implications and applications to High Energy and Nuclear Astrophysics.  The talk will focus on Quark-Novae in the context of Super-Luminous Supernovae and in the context of the origin of heavy elements (r-process nucleosynthesis). The Quark-Nova has the potential to provide new insight into  explosive astrophysical phenomena and the origin of some elements in the periodic table, by naturally combining  the might of researchers in nuclear physics, sub-nuclear physics and astrophysics. Rachid Ouyed (UofC)
        Speaker: Prof. Rachid Ouyed (University of Calgary)
      • 125
        Hadronic-to-Quark-Matter Phase Transition: Effects of Strange Quark Seeding.
        When a massive star depletes its fuel it may undergo a spectacular explosion; the supernova. If the star is massive enough, it can undergo a second explosion; the Quark nova. The origin for this second explosion has been argued to be the transition from Hadronic-to-Quark-Matter (Ouyed et al. 2013). Hadronic-to-Quark-Matter phase transition occurs when hadronic (nucleated) matter under high temperatures and/or densities deconfines into what is called a quark-gluon plasma (QGP). This talk will explore the required conditions for a star to undergo a Quark nova. In particular, under which conditions should the transition from Hadronic-to-Quark-Matter occur so that there is a second explosion for a massive star? The talk will be at an introductory level and will present the results of theoretical and computational calculations performed to estimate the production rate of strange quarks by self-annihilation of dark matter determining whether or not dark matter self-annihilation can be responsible by itself to start a combustion in the core of a star for it to undergo a Quark nova.
        Speaker: Mr Luis Welbanks (University of Calgary)
    • M2-6 Radiation Therapy (DMBP-DNP) / Thérapie par rayonnement (DPMB-DPN) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Melanie Martin (University of Winnipeg)
      • 126
        Medical linear accelerator mounted mini-beam collimator: transferability study
        Background: In place of the uniform dose distributions used in conventional radiotherapy, spatially-fractionated radiotherapy techniques employ a planar array of parallel high dose ‘peaks’ and low dose ‘valleys’ across the treatment area. A group at the Saskatchewan Cancer Agency have developed a mini-beam collimator for use with a medical linear accelerator operated at a nominal energy of 6MV. Purpose: The goal of this work was to characterize various attributes of the mini-beam collimated dose distribution and assess consistency of those attributes across a set of medical linear accelerators. Materials and Methods: Three “beam matched” Varian iX accelerators were used in this study. All measurements were made using a PTW scanning water tank set with a 100 cm source to surface distance. Dose profiles perpendicular to the plane of the mini-beam collimator were measured at a depth of 10.0 cm for a square field of side 4.0 cm. Percentage depth dose (PDD) curves along the central peak dose were made for a square field of side 4.0 cm. Relative point dose measurements were made at a depth of 10.0 cm along the central peak dose using two different diode detectors (PTW TN60017 and IBA stereotactic field diode (SFD)). A collimator factor (CF), defined as the ratio of the collimated point dose to that of the open field point dose, was determined at a depth of 10 cm for each linac for square field sizes of side 2.0, 3.0, 4.0 and 5.0 cm. Results: When normalized to the central peak dose, the profile data revealed a variation in the relative valley dose across the three linacs. However, the PDD data was consistent indicating no variation in beam energy across the three linacs. As previously determined, the measured CF did differ as a function of detector. This results from the active volume of the detectors being different. The measured CF also differed across the set of linacs. The PTW diode measurements showed an average difference of 2.65% across accelerators, and the SFD showed an average difference of 5.6% across accelerators. The difference in CF and valley dose is believed to result from differences in the electron source width incident on the Bremsstrahlung target for each of the accelerators. Conclusion: The dose profile and collimator factors of the mini-beam collimated dose were not found to be consistent across a set of medical linear accelerators.
        Speaker: Mr William Davis (Department of Physics and Engineering Physics, University of Saskatchewan)
        Slides
      • 127
        Cancer cell targeting gold nanoparticles for therapeutics
        Polyethylene glycol (PEG) has promoted the prospective cancer treatment applications of gold nanoparticles (GNPs). *In vivo* stealth of GNPs coated with PEG (PEG-GNPs) takes advantage of the enhanced permeability and retention effect in tumor environments, making them suitable for targeted treatment. Because PEG minimizes gold surface exposure, PEG-GNP interaction with ligands that mediate cancer cell uptake is lower than uncoated GNPs. Hence, the cellular uptake of PEG-GNPs is significantly lower than uncoated GNPs *in vitro*. As intracellular localization of GNPs maximizes its therapeutic enhancement, there is a need to improve the uptake of PEG-GNPs. To enhance uptake, receptor mediated endocytosis peptides were conjugated with PEG-GNPs of varying core sizes. Spherical GNPs of diameters 14 nm, 50 nm and 70 nm and a PEG chain length of 2 and 5 kDa were used to determine a preferred core size and chain length for uptake *in vitro* in HeLa and MDA-MB-231 cells. Radiosensitization of HeLa cells to a 6 MVp clinical photon beam via GNP conjugates were observed to assess its therapeutic application.
        Speaker: Charmainne Cruje (Ryerson University)
      • 128
        Development and Imaging of the World’s first Whole-Body Linac-MRI Hybrid System
        **Purpose:** We designed and first whole-body clinical linac-MRI hybrid (linac-MR) system to provide real-time MR guided radiotherapy with current imaging and treatment. Installation began in our clinic in 2013, and the world-first images from a linac-MR on a human volunteer were obtained in July 2014. **Methods:** The linac-MR consists of an isocentrically mounted 6 MV linac that rotates in-unison with a biplanar 0.6 T MRI in transverse plane. The Bo field and the central axis of the 6 MV beam are parallel to each other. The optimized fringe field results in insignificant increase in entrance dose. The parallel configuration avoids large increases in dose at tissue/air interfaces and at beam exit due to electron return effect that occurs in the perpendicular configuration. We were first to demonstrate concurrent MR imaging and linac-irradiation of head-size phantoms in 2008, on a single gantry. The head prototype have been described in our 40 peer-reviewed articles (linac-MR.ca/publications.html). The current functional whole-body rotating linac-MR system is built on the engineering and physics obtained from the head prototype. **Results:** The current system is mechanically well balanced and rotates at 1 rpm. The 3D magnetic field mapping demonstrates minimal perturbation in magnetic field homogeneity with gantry rotation which is easily and effectively shimmed by gradient coils. The Larmor Frequency varies with gantry angle due to the Bo interaction with room shielding and to the directional changes of the Earth’s magnetic relative, and closely follows our predictions calculated previously. Angle dependent 3D magnetic field maps and Larmor Frequency are used to automatically and optimally create image acquisition parameters for any gantry angle. Metrics obtained at different rotating angles show that the image quality is comparable to those of clinical MRI systems, and thus satisfy the requirements for real-time MR-guided radiotherapy. **Conclusions:** The system highlights are: 1) 6 MV linac, 2) high-quality MR images during irradiation, 3) simultaneous linac and MR rotation in parallel configuration to avoid strong angle-dependent shimming, and to avoid increased dose at beam exit and tissue/air interfaces, 3) installation through the maze of an existing vault, 4) cryogen-free superconducting magnet not requiring a helium vent, and 5) ability to turn magnet off or on in a few minutes for servicing.
        Speaker: Prof. B. Gino Fallone (University of Alberta)
      • 129
        A SYSTEMATIC APPROACH TO STANDARDIZING SMALL FIELD DOSIMETRY IN RADIOTHERAPY APPLICATIONS
        Small field dosimetry is difficult, yet consistent data is necessary for the clinical implementation of advanced radiotherapy techniques. In this work we present improved experimental approaches required for standardizing measurement, Monte Carlo (MC) simulation based detector correction factors as well as methods for reporting experimental data. A range of measurements and MC modelling studies have been reported by our group. Based on these methods and results, recommendations are given as to: (1) commissioning/fine-tuning MC models for use in small field dosimetry, (2) correction factors for a range of shielded and unshielded diode detectors, (3) what constitutes a ‘very small field size’ - based on the different effects as field size gets smaller, (4) measurement methods necessary to control uncertainties at these very small field sizes and (5) reporting against an effective field size - taking into account measured dosimetric field size. The results of the work clearly show that measurement and modelling based methods can be standardized to improve the consistency in small field dosimetry. Through standardization the best accuracy possible can be achieved in these increasingly clinically-used conditions.
        Speaker: Dr Gavin Cranmer-Sargison (Department of Medical Physics, Saskatchewan Cancer Agency)
      • 130
        Multifunctional perfluorocarbon nanoemulsions for cancer therapy and imaging
        There is interest for the use of nanoemulsions as therapeutic agents, particularly Perfluorocarbon (PFC) droplets, whose amphiphilic shell protects drugs against physico-chemical and enzymatic degradation. When delivered to their target sites, these PFC droplets can vaporize upon laser excitation, efficiently releasing their drug payload and/or imaging tracers. Due to the optical properties of gold, coupling PFC droplets with gold nanoparticles significantly reduces the energy required for vaporization. In this work, nanoemulsions with a perfluorohexane core and Zonyl FSP surfactant shell were produced using an oil-in-water technique. Droplets were characterized in terms of size and morphology using high resolution fluorescence techniques (i.e. Total Internal Reflection Fluorescence Microscopy, TIRFM, and Fluorescence Correlation Spectroscopy, FCS), electron microscopy, and light scattering techniques (i.e. Dynamic Light Scattering, DLS). The ability of PFC droplets to vaporize are demonstrated using Optical Microscopy (OM). Our emulsion synthesis technique has given a reproducible, unimodal size distribution of PFC droplets corresponding to an average hydrodynamic diameter of 53.5 ± 3.8 nm, from DLS and FCS, with long-term stability at physiological conditions. Their size and stability makes them cost effective drug delivery vehicles suitable for efficient internalization within cancer cell lines. To vaporize the nanoemulsions, silica coated gold nanoparticles (scAuNPs) were used and excited with a 532 nm laser. Taken together, TIRFM, dual-colour FCS, and OM show that scAuNPs are within the same diffraction-limited spot of these PFC droplets before vaporization.
        Speaker: Mr Donald A. Fernandes (Ryerson University)
    • M2-7 Cosmic frontier: Dark matter I (PPD-DTP) / Frontière cosmique: matière sombre I (PPD-DPT) CCIS L1-160

      CCIS L1-160

      University of Alberta

      Convener: Kevin Graham (Carleton University)
      • 131
        Status of Dark Matter Theories
        The existence of dark matter is a prominent puzzle in model physics, and it strongly motivates new particle physics beyond the standard model.I will review theoretical candidates for dark matter as proposed in the literature, and their status in light of recent experimental searches. I will also discuss new possibilities of dark matter theories and related research avenues.
        Speaker: Yanou Cui (Perimeter Institute)
        Slides
      • 132
        The DEAP-3600 Dark Matter Experiment -- Updates and First Commissioning Data Results
        The DEAP-3600 experiment uses 3.6 tons of liquid argon for a sensitive dark matter search, with a target sensitivity to the spin-independent WIMP-nucleon cross-section of 10^{-46} cm^2 at 100 GeV WIMP mass. This high sensitivity is achievable due to the large target mass and the very low backgrounds in the spherical acrylic detector design as well as at the unique SNOLAB facility. Scintillation light in liquid argon is collected with 255 high efficiency photomultiplier tubes. Pulse shape discrimination is used to reject electromagnetic backgrounds from the WIMP induced nuclear recoil signal. We have started taking commissioning data. In this talk we will present the status of the experiment and results from analysis of the first commissioning data.
        Speaker: Dr Bei Cai (Queen's University)
      • 133
        Direct Detection Prospects for Higgs-portal Singlet Dark Matter
        There has recently been a renewed interest in minimal Higgs-portal dark matter models, which are some of the simplest and most phenomenologically interesting particle physics explanations of the observed dark matter abundance. In this talk, we present a brief overview of scalar and vector Higgs-portal singlet dark matter, and discuss the nuclear recoil cross sections of the models. We show that, given a reasonable range for the theoretical uncertainties in the calculation, the expected cross sections are found in the region of the parameter space that will be probed by next generation direct detection experiments. In particular, within two years of operation the XENON1T experiment should be able to make a strong statement about Higgs-portal singlets.
        Speaker: Fred Sage (University of Saskatchewan)
      • 134
        Status of the PICO-60 Dark Matter Search Experiment
        The PICO collaboration (formerly PICASSO and COUPP) uses bubble chambers for the search for Weakly Interacting Massive Particle (WIMP) dark matter. Such bubble chambers are scalable, can have large target masses and can be operated at regimes where they are insensitive to backgrounds such as beta and gamma radiation. The PICO-60 experiment is a bubble chamber that has been developed and operated at SNOLAB with 37 kg of CF$_3$I as a target liquid. The experiment is currently being upgraded for the use with 60 kg of ultra clean C$_3$F$_8$ to focus on the search for spin dependent dark matter. The PICO-60 detector is expected to have a world leading sensitivity to spin dependant dark matter interactions. In this talk an overview of the progress of PICO-60 experiment, the results from the dark matter runs with existing data and future plans are presented.
        Speaker: Pitam Mitra (University of Alberta)
        Slides
    • M2-8 Teaching Physics to a Wider Audience (DPE) / Enseigner la physique à un auditoire plus vaste (DEP) CAB 239

      CAB 239

      University of Alberta

      Convener: Adam Sarty (Saint Mary's University)
      • 135
        Asymmetric Wavefunctions from Tiny Perturbations
        We present an undergraduate-accessible analysis of a single quantum particle within a simple double well potential through matrix mechanics techniques. First exploring the behavior in a symmetric double well (and its peculiar wavefunctions), we then examine the effect that varying well asymmetry has on the probability density. We do this by embedding the potential within a larger infinite square well, expanding in this simple basis, and solving for the matrix elements. The resulting wavefunctions are drastically different than those of the unperturbed system. A relatively tiny drop in one of the well depths results in a nearly complete collapse (localization) of the wavefunction into one of the wells. This system can be accurately mapped to a much simpler two-state "toy model"; this makes it clear that this localization is also a property of a generic double well system.
        Speaker: Tyler Dauphinee
      • 136
        An online resource for teaching about energy
        Energy issues are important to Canada, and a logical topic for Canadians to teach. The Energy Education group at the University of Calgary has built a free on-line resource suitable for teaching an 'energy for everyone' course from a physics department. This resource includes interactive data visualizations and real world simulations to help students understand the role of energy in modern society
        Speaker: Prof. Jason Donev (University of Calgary)
      • 137
        Essential Psychology in Physics - MBTI and You
        According to the wikipedia entry, psychology is an academic and applied discipline that involves the scientific study of mental functions and behaviours. Since learning involves mental functions, it only makes sense that psychology has a role in the classroom - including a post-secondary physics class. The Myers-Briggs Type Indicator (MBTI) is one model that provides a framework for identifying differences in how individuals perceive the world, make decisions, and communicate. By becoming aware of one's own type, individuals can understand why they may be perceived as 'different' from their colleagues, which is often more than just their gender. Furthermore, utilizing MBTI can help instructors become more effective in the classroom by maximizing their strengths and minimizing their vulnerabilities. In this talk, I will present an introduction to MBTI, and give some ideas on how to use this framework to improve working relationships both inside and outside the classroom.
        Speaker: Dr Jo-Anne Brown (University of Calgary)
      • 138
        Essential Psychology in the Physics Classroom - Five Steps to Improve Classroom Effectiveness
        Teaching large physics classes - especially to non-physics majors that may have developed an extraordinary aversion to anything math-related - can be a challenge, even for the best instructors. However, there are a few techniques, drawn from psychology, that can help improve the experience for both the instructor and the students. In this talk, I will present a 'five-step program' I developed that works effectively for any level of class I teach. The result of this program has been high student satisfaction for the course, as well as a retention of my sanity.
        Speaker: Jo-Anne Brown (University of Calgary)
    • M2-9 Advanced Instrumentation at Major Science Facilities: Accelerators (DIMP) / Instrumentation avancée dans des installations scientifiques majeures: accélérateurs (DPIM) CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Kirk Michaelian (Natural Resources Canada)
      • 139
        CLS 2.0: The Next 10 Years
        The Canadian Light Source (CLS) is Canada’s premier source of intense light for research, spanning from the far infrared to hard x-rays. The facility has been in operations for 10 years and in that time has hosted over 2,000 researchers from academic institutions, government, and industry, from 10 provinces and 2 territories, and provided a scientific service critical in over 1,000 scientific publications. As the CLS reaches this important milestone, a series of workshops at the Annual Users’ Meeting (May 2015), will help define the scientific direction of the facility for the next 10 years, to address the Canadian research community’s scientific challenges. This presentation will present scientific and technical highlights from the CLS today and give an outlook of where photon science using light sources may go in the future.
        Speaker: Dr Dean Chapman (Canadian Light Source Inc.)
      • 140
        Acquaman: Scientific Software as the Beamline Interface
        The Acquaman project (Acquisition and Data Management) was started in early 2010 at the Canadian Light Source. Over the past four years, the project has grown to support five beamlines by providing beamline control, data visualization, workflow, data organization, and analysis tools. Taking advantage of modular design and common components across beamlines, the Acquaman team has demonstrated that a framework dedicated to synchrotron beamlines can deliver high quality interfaces while also reducing overall development cost and production time. Acquaman supports scientific researchers by allowing them to focus on the scientific techniques they know while reducing the need to understand specific hardware, which changes from beamline to beamline. Focus will be given to this topic in the broader context of how to manage a modular, scalable, and flexible framework. Additionally, two small case studies – the IDEAS and SXRMB beamlines – will be used to demonstrate the ease of deployment on new beamlines.
        Speaker: David Chevrier (Canadian Light Source)
        Slides
      • 141
        A Phase Space Beam Position Monitor for Synchrotron Radiation
        Synchrotron radiation experiments critically depend on the stability of the photon beam position. The position of the photon beam at the experiment or optical element location is set by the electron beam source position and angle as it traverses the magnetic field of the bend magnet or insertion device. An ideal photon beam monitor would be able to measure the photon beam’s position and angle, and thus infer the electron beam’s position in phase space. Monochromatic x-ray beams at synchrotrons are typically prepared by x-ray diffraction from crystals usually in the form of a double crystal monochromator. Diffraction couples the photon wavelength or energy to the incident angle on the lattice planes within the crystal. The beam from such a monochromator will contain a spread of energies due to the vertical divergence of the photon beam from the source. This range of energies can easily cover the absorption edge of a filter element such as iodine at 33.17 keV. A vertical profile measurement with and without the filter can be used to determine the vertical angle and position of the photon beam. In these measurements an imaging detector measures these vertical profiles with an iodine filter that horizontally covers part of the monochromatic beam. The goal was to investigate the use of this combined monochromator, filter and detector as a phase space beam position monitor. The system was tested for sensitivity to position and angle under a number of synchrotron operating conditions, such as normal operations and special operating modes where the beam is intentionally altered in position and angle. The results are comparable to other methods of beam position measurements and indicate that such a system is feasible in situations where part of the white synchrotron beam can be used for the phase space measurement.
        Speaker: Nazanin Samadi (University of Saskatchewan)
      • 142
        Observation of Wakefields in Coherent Synchrotron Radiation at the Canadian Light Source
        Synchrotron light sources routinely produce brilliant beams of light from the infrared to hard X-ray. Typically, the length of the electron bunch is much longer than the wavelength of the produced radiation, causing the electrons to radiate incoherently. Many synchrotron light sources, including the Canadian Light Source (CLS), can operate in special modes where the electron bunch, or structures in the electron bunch, are small enough that they radiate coherently, producing coherent synchrotron radiation (CSR). Using a Michelson interferometer and RF diodes at CLS, we observe structure in THz CSR which is due to the electromagnetic wake following the electron bunch. The RF diode measurements provide direct observations of the wakefields, and we compare against wakefield simulations. Given the complexity of the vacuum chamber geometry, the agreement between simulation and measurement is quite satisfactory.
        Speaker: Ward Wurtz (Canadian Light Source Inc.)
        Slides
    • Welcome BBQ Reception / Réception d'accueil avec BBQ CCIS Ground Level Foyer

      CCIS Ground Level Foyer

      University of Alberta

    • Herzberg Memorial Public Lecture - Miguel Alcubierre, National Univ. of Mexico / Conférence commémorative publique Herzberg - Miguel Alcubierre, National Univ. of Mexico Myer Horowitz Theatre

      Myer Horowitz Theatre

      University of Alberta

      Convener: Robert Fedosejevs (University of Alberta)
      • 143
        Faster than the Speed of Light
        In this talk I will give a short introduction to some of the basic concepts of Einstein’s special theory of relativity, which is at the basis of all of modern physics. In particular, I will concentrate on the concept of causality, and why causality implies that nothing can travel faster than the speed of light in vacuum. I will later discuss some of the basic ideas behind Einstein’s other great theory, General Relativity, which is the modern theory of gravity and postulates that the geometry space-time is dynamic and the presence of large concentrations of mass and energy produce a “curvature” in space-time. I will then talk about how the curvature of space-time can be used in several ways to travel “faster than the speed of light” by distorting the geometry away from that of flat space. In particular, I will discuss the ideas behind the geometric model for a “warp drive”.
        Speaker: Prof. Miguel Alcubierre (National University of Mexico)
    • Post-talk Reception Dinwoodie Lounge

      Dinwoodie Lounge

      University of Alberta

    • CAP Foundation Annual General Meeting / Assemblée annuelle de la Fondation de l'ACP CCIS 4-285

      CCIS 4-285

      University of Alberta

      Convener: Robert Mann (University of Waterloo)
    • Exhibit booths open 08:30-16:00 / Salle d'exposition ouverte de 08h30 à 16h00 CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • Teachers' Day - Session I / Journée des enseignants - Atelier I CCIS L1-047

      CCIS L1-047

      University of Alberta

      • 144
        Opening and Welcome, Calvin Kalman from CAP
      • 145
        Changing student's approach to learning physics, Calvin Kalman, Chair of CAP Division of Physics Education
      • 146
        Metamaterials: Controlling light,heat,sound and electrons at the nanoscale, Zubin Jacob, Electrical and Computer Engineering, UofA
    • T-PUB Commercial Publishers' Session: Resources to Enhance University Physics Teaching (DPE) / Session des éditeurs commerciaux : Ressources visant à améliorer l’enseignement de la physique à l’Université (DEP) CCIS L1-029

      CCIS L1-029

      University of Alberta

      Convener: Don Mathewson (Division of Physics Education, CAP)
      • 147
        Pearson Education’s digital resources for supporting Physics teaching: Mastering Physics
        This presentation will provide an overview of the online resources which Pearson Education can provide to help support your university physics teaching. We will begin with an overview of how one faculty member has implemented and used Pearson resources in his first-year physics course sequence, and the plans in place for including further tools in the coming year. The presentation will then review other available tools that can help enhance your teaching toolkit.
        Speakers: Adam Sarty (Saint Mary's University), Mrs Claire Varley (Customer Experience Manager – Higher Education, Pearson Canada)
        Slides
      • 148
        A panel discussion of PER and Enhanced WebAssign in teaching physics
        Join Nelson Education and some of Canada’s leading physics educators for a demonstration of enhanced WebAssign and a discussion around physics education research in practice including the use of digital learning tools to promote better learning outcomes.
        Speakers: Ernie McFarlane (University of Guelph), Marina Milner-Bolotin (The University of British Columbia), Martin Williams (University of Guelph)
    • T1-1 Superconductivity (DCMMP) / Supraconductivité (DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Tatiana Rappoport (Federal University of Rio de Janeiro)
      • 149
        Scanning Tunneling Spectroscopy of LiFeAs
        LiFeAs is one of several pnictide and chalcogenide superconductors that can be grown in single-crystal form with relatively few defects. Spectroscopy away from any native defects reveals a spatially uniform superconducting gap, with two distinct gap edges. Quasiparticle interference over the gap energy range provides evidence for an S+- pairing state. We further explore the spectroscopy of both native, and deliberately introduced defects and compare to theoretical calculations for defects in an S+- superconductor.
        Speaker: Prof. D,A. Bonn (University of British Columbia)
      • 150
        Interplay of charge density waves and superconductivity
        We examine possible coexistence or competition between charge density waves (CDW) and superconductivity (SC) in terms of the extended Hubbard model. The effects of band structure, filling factor, and electron-phonon interactions on CDW are studied in detail. In particular, we show that van Hove singularities per se can lead to the formation of CDW, due to a substantial energy gain by electron-phonon coupling. While this is contrary to the conventional view that CDW are caused by nesting of Fermi surfaces, it is consistent with recent experimental findings.
        Speaker: Kaori Tanaka (University of Saskatchewan)
      • 151
        Quantum oscillation studies of quantum criticality in PrOs$_4$Sb$_{12}$
        PrOs$4$Sb${12}$ is a cubic metal with an exotic superconducting ground state below 1.8 K. The crystal fields around the Pr site are such that it has a singlet ground state and a magnetic triplet just 8K above the ground state. Under an applied magnetic field, the triplet splits, and the S$_z = +1$ state crosses the singlet state at easily accessible magnetic fields. In the region of the level crossing the ground state reconstructs, creating a so-called “antiferroquadrupolar” (AFQ) phase that exists at temperatures below $1$ K and magnetic fields between about $4.5$ and $12$ tesla. This state offers a rare opportunity to observe the behaviour of quantum oscillations upon crossing a phase transition. In a recent paper [$1$] we argued that the lower boundary of the AFQ phase should have exotic behaviour as T $\rightarrow 0$ K due to mixing of hyperfine states with the AFQ order. We will describe our attempts to observe this behaviour via magnetic susceptibility and quantum oscillation measurements. [$1$] A. McCollam, B. Andraka and S. R. Julian, Physical Review B 88 (2013) 075102.
        Speaker: Dr Stephen Julian (University of Toronto)
      • 152
        A Variational Wave Function for Electrons coupled to Acoustic Phonons
        We survey briefly the electron-phonon interactions in metals with an emphasis on applications in electron-phonon mediated superconductivity. While BCS theory and Eliashberg theory have significant predictive power, the microscopic Hamiltonians for the processes they describe are still an open area of study. We will examine the hitherto unsolved BLF-SSH model of electrons interacting with acoustical phonons and present a novel variational wave function for the solution of this model. We examine the validity of this variational wave function across applicable parameter regimes.
        Speaker: Carl Chandler (University of Alberta)
    • T1-10 THz science and applications (DAMOPC) / Sciences et applications des THz (DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Matt Reid (University of northern british columbia)
      • 153
        Ultrafast dynamics of mobile charges and excitons in hybrid lead halide perovskites
        In this talk we discuss recent experiments using ultra-broadband time-resolved THz spectroscopy (uTRTS) studying charge and excitonic degrees of freedom in the novel photovoltaic material CH3NH3PbI3. This technique uses near single-cycle and phase stable bursts of light with an ultra-broad bandwidth spanning 1 - 125 meV to take snapshots of a material's dielectric function or optical conductivity on femtosecond time scales after photoexcitation. These transient spectra reveal free charge transport properties on unprecedented time scales, and at the same time can probe internal excitations of Coulombically bound excitons. It is therefore an ideal technique for studying materials related to solar energy conversion such as semiconducting polymers, quantum dots and even the new hybrid metal halide perovskites. We apply uTRTS to a single crystal of CH3NH3PbI3, temporally resolving the charge carrier generation dynamics, the screening of infrared active phonons and the dissociation of excitons. Our measurements reveal remarkably high charge carrier mobilities on ultrafast time scales, as well as the importance of screening at elevated carrier densities.
        Speaker: David Cooke (McGill University)
      • 154
        Carrier dynamics in semiconductor nanowires studied using optical-pump terahertz-probe spectroscopy
        The advance of non-contact measurements involving pulsed terahertz radiation presents great interests for characterizing electrical properties of a large ensemble of nanowires. In this work, InP and Si nanowires grown by molecular beam epitaxy or by chemical vapor deposition on silicon substrates were characterized using optical-pump terahertz probe (OPTP) transmission experiments. The influence of various fabrication parameters (v.g. doping and NW diameter) on the carrier dynamics has been investigated. Photocarrier lifetimes and mobilities can be extracted from such OPTP measurements.
        Speaker: Prof. Denis Morris (Département de physique, Université de Sherbrooke)
      • 155
        Towards quantum repeaters using frequency multiplexed entanglement
        Quantum communication is based on the possibility of transferring quantum states, generally encoded into so-called qubits, over long distances. Typically, qubits are realized using polarization or temporal modes of photons, which are sent through optical fibers. However, photons are subject to loss as they travel through optical fibers or free space, which sets a distance barrier of around 100 kilometers. In classical communications, this problem can be straightforwardly solved by amplification, but this is not an option in quantum mechanics because of the non-cloning theorem. Fortunately, photon loss can be overcome by implementing quantum repeaters [1], which create long-distance entanglement via entanglement swapping from shorter-distance entanglement links. Such protocols require the capacity to create entanglement in a heralded fashion, to store it in quantum memories, retrieve it after feed-forward information, and to swap it. A variety of architectures and protocols have been proposed for implementing quantum repeaters [2]. Ideally, a quantum repeater protocol should minimize the physical resources required to establish entanglement between two points. Our team is working on a specific quantum repeater scheme that explores frequency multiplexing. This will allow us to increase the probability of generating short-distance entanglement, with a success rate close to 100%, while taking maximum benefit of the quantum memories developed by other members of our group [3]. The proposed scheme requires quantum memories and entangled photons pair sources capable to work in the frequency multiplexing domain. This presentation will focus on the description of the general scheme and on the multiplexed entangled photon pair sources that we are developing.
        Speaker: Mr Pascal Lefebvre (University of Calgary)
      • 156
        True Random Number Generation based on Interference between Two Independent Lasers
        Reliable true random number generation is essential for information theoretic security in a quantum cryptographic system based on quantum key distribution (QKD) and one-time pad encryption [1]. Various random number generation methods have already been proposed and demonstrated, such as schemes based on the detection of single photons [2], whose rate is limited by the dead time of single photon detectors. Alternative approaches are based on the chaotic light emission from a semiconductor laser [3, 4]. In this talk we propose and demonstrate a novel scheme to generate random numbers based on interference between two independent lasers, i.e. a continuous wave (CW) laser and a gain-switched pulsed laser, each emitting light at around 1550 nm wavelength. The physical basis of our random number generator is the randomness of the phase difference between light emitted from the two independent lasers. Using only off-the-shelf components, we achieve a random number generation rate of 250 MHz. The properties of the generated random numbers are tested using National Institute Standards and Technology (NIST) statistical test suite. We also discuss the extension of our methods from random bits to randomly selected symbols with more than two different values. References [1] N. Gisin, and R. Thew, “Quantum communication,” Nature Photon. 1, 165 (2007). [2] A. Stefanov, N. Gisin, O. Guinnard, L. Guinnard, and H. Zbinden, “Optical quantum random number generator,” J. Mod. Opt. 47, 595 (2000). [3] T. Symul, S. M. Assad, and P. K. Lam, “Real time demonstration of high bitrate quantum random number generation with coherent laser light,” Appl. Phys. Lett. 98, 231103 (2011). [4] A. Uchida, K. Amano, M. Inoue, K. Hirano, S. Naito, H. Someya, I. Oowada, T. Kuashige, M. Shiki, S. Yoshimori, K. Yoshimura, and P. Davis, “Fast physical random bit generation with chaotic semiconductor lasers,” Nature Photon. 2, 728 (2008).
        Speaker: Caleb John (University of Calgary)
        Slides
    • T1-11 Medical Imaging (DMBP) / Imagerie médicale (DPMB) CAB 239

      CAB 239

      University of Alberta

      Convener: Melanie Martin (University of Winnipeg)
      • 157
        The Rate of Reduction of Defocus in the Chick Eye is Proportional to Retinal Blur
        PURPOSE. Calculations of retinal blur and eye power are developed and used to study blur on the retina of the growing chick eye. The decrease in defocus and optical blur during growth is known to be an active process. Here we show that the rate of defocus reduction is proportional to the amount of blur on the retina. METHODS. From literature values of chick eye parameters, the amounts of defocus and optical axial length were fitted as a function of age. Pupil size was used to calculate blur on the retina due to defocus. Eye length and calculated eye power were compared up to day 75 to examine their contributions to decreasing retinal blur. Novel equations were used to calculate eye power and a new definition of the end point of active defocus reduction is introduced. RESULTS. During initial growth, eye length increases while blur from defocus decreases. Eye power decreases exponentially reaching and closely matching eye length after day 35. This gives an almost stable value of defocus beyond day 50. Retinal blur decreases almost exponentially until between days 40 and day 50. After day 50, angular retinal blur changes in agreement with predictions of a uniformly expanding eye model and passive growth. CONCLUSIONS. Concurrent variations in eye power and length produce smaller changes in defocus. We define the time at which angular retinal blur becomes stable as the completion of active reduction of defocus. Prior to this time, the rate of defocus reduction is proportional to the amount of blur on the retina. After this time, the measured eye properties are consistent with uniform eye expansion and angular blur is close to the presumed resolution limit of the cone photoreceptors. The eye power calculation presented is accurate and simpler than other approaches without the need for additional dimensional data.
        Speaker: Prof. Melanie Campbell (University of Waterloo)
      • 158
        Image Analysis and Quantification for PET Imaging
        Introduction: Positron emission tomography (PET) is a highly sensitive, quantitative and non-invasive detection method that provides 3D information on biological functions inside the body. There are several factors affecting the image data, including normalization, scattering, and attenuation. In this study we have quantified the effect of scattering and attenuation corrections on the PET data. Methods: The image quality phantom (approximating the size of a mouse) was modified to match the diameters of the rat and monkey count rate phantoms by creating high density polyethylene (HDPE) sleeves that fit over the standard phantom. The emission and transmission data from the phantom, filled with 18F, were acquired with a microPET P4 scanner. The data were histogrammed, reconstructed, using various algorithms, with required corrections applied, including normalization and physical decay of 18F. The data were analyzed using volume of interest (VOI) analysis with and without attenuation or scattering corrections. Signal–to-noise ratio values were calculated and the results were correlated with the phantom size, correction methods and reconstruction algorithm. Results: The signal to noise using OSEM3D/MAP algorithm provided the highest signal-to-noise ratio values for all three phantoms, followed by OSEM2D. Since both are iterative algorithms and reduce the noise in the images. Attenuation correction, along with scattering correction had a significant impact on the quantitative results. Conclusion: Both attenuation and scattering corrections need to be included in image quantification for PET imaging. OSEM3D/MAP provides the images with highest signal-to-noise ratio values.
        Speaker: Dr Esmat Elhami (University of Winnipeg)
      • 159
        Magnetic Susceptibility Mapping in Human Brain using High Field MRI
        Magnetic Resonance Imaging (MRI) is a powerful imaging method for examining hydrogen protons and their local environment. Inferences can be made about the local environment from the signal relaxation (decay or recovery) or phase evolution. For many years, phase images were largely discarded in favor of magnitude images only, which dominate clinical MRI. Although the sensitive nature of phase images to magnetic field perturbations can cause a high degree of artifact, phase images also provide a means to examine the underlying local susceptibility distribution. Extraction of the local susceptibility requires removing nonlocal field effects that arise from strong air-tissue susceptibility differences, then performing an ill-posed inverse problem on the local magnetic field to yield the susceptibility map. This emerging MRI research area named Quantitative Susceptibility Mapping (QSM) provides a means to discriminate between tissues such as myelin, calcium and iron. This talk will introduce QSM and explore its value in human brain, particularly for measurement of iron accumulation in grey matter. These measures are further enhanced by using higher magnetic field strengths, greater than the clinical standards of 1.5 and 3.0 T. The value of these stronger magnetic fields will also be explored.
        Speaker: Dr Alan Wilman (University of Alberta)
      • 160
        Correlating quantitative MR changes with pathological changes in the white matter of the cuprizone mouse model of demyelination
        Mouse brain white matter (WM) damage following the administration of cuprizone was studied weekly using diffusion tensor imaging, quantitative magnetization transfer imaging, T2-weighted MRI (T2w), and electron microscopy (EM). A previous study examined correlations between MR metrics and EM measures after 6 weeks of feeding. The addition of weekly *ex vivo* tissue analysis allows for a more complete understanding of the correlations between MR metrics and EM measures of tissue pathology. Signal inversion is apparent in the T2w images as the number of weeks of cuprizone feeding increased. A decreased magnetization transfer ratio (MTR) is observed in the WM regions of the cuprizone mouse as cuprizone feeding continued. Many changes are observed in the *ex vivo* data including directionality changes in the external capsule in the directional encoded map of diffusion tensor imaging from weeks 1 to 6. From the EM images, myelinated axons are apparent in both cuprizone and control mice. Cuprizone is associated with oligodendroglial swelling and apoptosis. The significant change between control and cuprizone mice in the corpus callosum peaks in T2w at week 3 whereas it peaks at week 4 in MTR. The first large change in T2w occurs between weeks 2 and 3 in the external capsule and between weeks 3 and 4 in the MTR. Radial diffusivity appears to be different between control and cuprizone mice even in week 1. The weekly changes in radial diffusivity follow a different time course than MTR and T2 in the cuprizone mouse. The different time courses of the MR metrics suggest that T2, MTR and diffusivity are sensitive to different pathological features in WM. ANOVA will be used to determine when significant changes occur in MRI metrics. EM analysis of the tissue is in progress for correlations with WM pathology. Visually it can be seen in the EM images at week 3 that the control and cuprizone corpus callosum show a similar amount of myelinated axons. Our results are consistent with EM from other studies suggesting MTR likely reflects demyelination. The addition of the weekly *ex vivo* tissue analysis allows for a more complete understanding of the correlations between MR metrics and EM measures of tissue pathology.
        Speaker: Prof. Melanie Martin (Physics, University of Winnipeg, Radiology, University of Manitoba)
        Slides
      • 161
        Interstitial point radiance spectroscopy in turbid media
        Optical spectroscopy has become a valuable tool in biomedical diagnostics because of its ability to provide biochemical information on endogenous and exogenous chromophores present in tissues. In this work, point radiance spectroscopy using a white light source is investigated 1) to measure the optical properties of bulk tissues and 2) to detect localized gold nanoparticles in tissue mimicking Intralipid and porcine muscle phantoms. An angular sensitive detector made from a side-firing fiber was developed and used to measure the angular distribution of light (up to 180 degree rotation of the fiber) in selected locations in a phantom. Rotation provides angular optical data for analysis. An alternative approach is to use non-directional fluence data, but for optical property recovery, this requires translation of the fiber which is not desirable. In our radiance approach, the white light source also provides some spectroscopic information (focused in the 650-900 nm band) in addition to spatial information of a target (i.e. gold nanoparticles). We have measured the effective attenuation coefficient, diffusion coefficient, absorption coefficient and reduced scattering coefficient of Intralipid phantoms and thermally coagulated porcine muscle. Further, gold nanoparticle inclusions embedded in tissue mimicking media and ex vivo tissues were detectable via a novel spectro-angular analysis technique. This work is focused on the development of a new optical fiber based tool for disease detection. Funding: NSERC Discovery Grant, Atlantic Innovation Fund, Canada Foundation for Innovation and Canada Research Chairs Program
        Speaker: Dr Bill Whelan (Dept of Physics, University of Prince Edward Island)
    • T1-2 Many body physics & Quantum Simulation (DAMOPC-DCMMP) / Physique des N corps et simulation quantique (DPAMPC-DPMCM) CAB 235

      CAB 235

      University of Alberta

      Convener: Shohini Ghose
      • 162
        Universal features of quantum dynamics: quantum catastrophes
        Tracking the quantum dynamics following a quench of a range of simple many-body systems (e.g. the two and three site Bose-Hubbard models, particles on a ring), we find certain common structures with characteristic geometric shapes that occur in all the wave functions over time. What are these structures and why do they appear again and again? I will argue that they are quantum versions of the catastrophes described by catastrophe theory [R. Thom (1975), V.I. Arnol’d (1975)]. Quantum catastrophes occur in quantum fields: they are singular in the mean-field limit and require second-quantization to be well behaved, i.e. the essential discreteness of the excitations of the quantum field needs to be taken into account for a quantum catastrophe to be regularized. They are second quantized versions of more familiar catastrophes such as rainbows and the bright lines on the bottom of swimming pools (although the latter are rarely described in these terms!). Their universality stems from the fact that they are generic (need no symmetry) and structurally stable (immune to perturbations) as guaranteed by catastrophe theory.
        Speaker: Duncan O'Dell (McMaster University)
        Slides
      • 163
        Hot and Cold Dynamics of Trapped Ion Crystals near a Structural Phase Transition
        Small arrays of laser-cooled trapped ions are widely used for quantum information research, but they are also a versatile mesoscopic system to investigate physics with a flavor reminiscent of familiar models in condensed matter. For example, in a linear rf Paul trap, laser-cooled trapped ions will organize into a linear array when the transverse confinement of the trap is strong enough; however, at a critical trap anisotropy the ions will undergo a symmetry–breaking structural transition to a two-dimensional zigzag configuration. We have studied what is effectively the melting behavior of the ion arrays near to the linear-zigzag transition. We have also investigated the classical non-equilibrium dynamics during rapid quenches of the transition in order to test the Kibble-Zurek mechanism of topological defect formation across a symmetry-breaking transition. In this talk I will present our current investigations of dynamics near the linear-zigzag transition at ultralow temperatures, corresponding to just a few quanta of thermal energy in the vibrations of the ion array. I will discuss our implementation of a new laser cooling technique for trapped Ytterbium ions and our progress towards experiments in the quantum regime. For example, we are interested in whether decoherence effects can be sufficiently suppressed to prepare superpositions of the symmetry-broken configurations.
        Speaker: Paul C Haljan (Simon Fraser University)
      • 164
        Simulating Anderson localization via a quantum walk on a one-dimensional lattice of superconducting qubits.
        Quantum walk (QW) on a disordered lattice leads to a multitude of interesting phenomena, such as Anderson localization. While QW has been realized in various optical and atomic systems, its implementation with superconducting qubits still remains pending. The major challenge in simulating QW with superconducting qubits emerges from the fact that on-chip superconducting qubits cannot hop between two adjacent lattice sites. In this talk, I discuss how to overcome this barrier and develop a gate-based scheme to realize the discrete time QW by placing a pair of qubits on each site of a 1D lattice and treating an excitation as a walker. It is also shown that various lattice disorders can be introduced and fully controlled by tuning the qubit parameters in our quantum walk circuit. We observe a distinct signature of transition from the ballistic regime to a localized QW with an increasing strength of disorder. Finally, an eight-qubit experiment is proposed where the signatures of such localized and delocalized regimes can be detected with existing superconducting technology.
        Speaker: Joydip Ghosh (University of Calgary)
        Slides
      • 165
        Cold Atom Metrology: Progress towards a New Absolute Pressure Standard
        Laser cooling and trapping of atoms has created a revolution in physics and technology. For example, cold atoms are now the standard for time keeping which underpins the GPS network used for global navigation. In this talk, I will describe a research collaboration between BCIT, UBC (Kirk Madison) and NIST (Jim Fedchak - Sensor Science Division) with the goal of creating a cold atom (CA) based primary pressure standard for the high- and ultra-high vacuum regimes: A cold, trapped atom can act as a sensitive detector for a particle that passes through its collision cross-section and imparts momentum to it. The collision event is registered if the sensor atom's momentum gain is high enough to escape the trap. Thus, an ensemble of confined atoms measures the flux of particles via the observed loss rate of sensor atoms from the trap. In short, the particle flux (pressure) passing through the sensor atom volume transduces a timing signal (loss rate). The loss rate is sensitive to the type of collision and to the trap depth confining the atoms [1]. These factors afford an opportunity to study collision physics and the physics of the trap while working towards a new standard. The advantages of a CA standard include the fact the sensor relies on immutable properties of atomic matter and their interactions and that it will be a primary pressure standard, tied directly to the second, a base SI unit. This absolute standard would provide a valuable alternative to gas expansion/orifice flow transfer standards currently in use. In this talk I will review the basic ideas supporting the science and technology, along with an update on our progress. [1] D. Fagnan, J. Wang, C. Zhu, P. Djuricanin, B. G. Klappauf, J. L. Booth and K. W. Madison, Phys. Rev. A 80, 022712, 2009.
        Speaker: Dr James Booth (British Columbia Institute of Technology)
    • T1-3 Ground-based / in situ observations and studies of space environment I (DASP) / Observations et études de l'environnement spatial, sur terre et in situ I (DPAE) CAB 243

      CAB 243

      University of Alberta

      Convener: Konstantin Kabin (RMC)
      • 166
        Exoplanet Atmospheres: Triumphs and Tribulations
        From the first tentative discoveries to veritable spectra, the last 15 years has seen a triumphant success in observation and theory of exoplanet atmospheres. Yet the excitement of discovery has been mitigated by lessons learned from the dozens of exoplanet atmospheres studied, namely the difficulty in robustly identifying molecules, the possible interference of clouds, and the permanent limitations from a spectrum of spatially unresolved and globally mixed gases without direct surface observations. Nonetheless the promise and expectation is that the next generation of space telescopes will have the capability of detecting atmospheric biosignature gases if they exist on planets orbiting nearby stars, and the vision for the path to assess the presence of life beyond Earth is being established.
        Speaker: Prof. Sara Seager (Massachusett institute of technology)
      • 167
        The Far-Infrared Universe: from the Universe's oldest ligth to the birth of its youngest stars
        Over half of the energy emitted by the Universe appears in the relatively unexplored Far-Infrared (FIR) spectral region, which is virtually opaque from the ground and must be observed by space-borne instrumentation. The European Space Agency (ESA) Planck and Herschel Space Observatories, launched together on 14 May 2009, have both provided pioneering observations in this spectral range from star and planet formation to the intensity and polarization of the cosmic microwave background. Herschel and Planck completed observations in April and October of 2013, respectively. Although data analysis efforts within the instrument teams are ongoing, both have provided data and analysis tools to ESA public archives, with more software updates and data releases expected to continue into 2015 and 2016, including the much anticipated Planck polarisation data and results. Recent Planck and Herschel results are presented with a discussion of the development of, and Canadian participation in, the future of FIR astrophysics.
        Speaker: Jeremy Scott (University of Lethbridge)
        Slides
      • 168
        Neutron Monitor Atmospheric Pressure Correction Method Based on Galactic Cosmic Rays tracing and MCNP Simulations of Cascade Showers
        Nuclear spallations accompanying Galactic Cosmic Ray (GCR) propagation through the atmosphere forms a so-called "cascade shower" by means of production of secondary protons, photons, neutrons, muons, pions and other energetic particles. World-wide Neutron Monitor (NM) network has been deployed for the ground-based monitoring of energetic protons and neutrons precipitations. Real time data from 36 NMs (including Calgary NM) are collecting in the Neutron Monitor Database (NMDB) [http://www.nmdb.eu]. However, each monitor has its own detection efficiency, which depends on NM location, design, operational and atmospheric parameters, so NM counting rates must be normalized. We developed and implemented a numerical technique which allows NM count rates estimation based on the spectrum of primary GCR, NM location, its internal design, and atmospheric parameters. Primary GCR are tracing to the top of atmosphere using our in-home computational tool [Kouznetsov, 2013]. The background proton and neutron particle fluxes are computed at Calgary NM location based on MCNP6 simulations and MSIS-E-90 Atmosphere Model [http://omniweb.gsfc.nasa.gov/vitmo/msis_vitmo.html]. Results obtained for Calgary NM improve standard atmospheric pressure correction procedure and can be used to normalize counting rates for the world-wide NM network.
        Speaker: Alexei Kouznetsov (University of Calgary)
      • 169
        Ionospheric Sounding Opportunities Using Signal Data From Pre-existing Amateur Radio And Operational Networks
        Amateur radio and other signals used for dedicated purposes, such as the Automatic Position Reporting System (APRS) and Automatic Dependent Surveillance Broadcast (ADS-B), are signals that exist for another reason, but can be used for ionospheric sounding. Whether mandated and government funded or voluntarily constructed and operated, these networks provide data that can be used for scientific and other operational purposes which rely on space weather data. Given the current state of the global economic environment and fiscal consequences to scientific research funding in Canada, these types of networks offer an innovative solution with pre-existing hardware for more real-time and archival space-weather data to supplement current methods, particularly for data assimilation, modelling and forecasting. Furthermore, the mobile ground-based transmitters offer more flexibility for deployment than stationary receivers. Numerical modeling has demonstrated that APRS and ADS-B signals are subject to Faraday rotation as they pass through the ionosphere. Ray tracing techniques were used to determine the characteristics of individual waves, including the wave path and the state of polarization at the satellite receiver. The modeled Faraday rotation was computed and converted to total electron content (TEC) along the ray paths. TEC data can be used as input for computerized ionospheric tomography (CIT) in order to reconstruct electron density maps of the ionosphere. The primary scientific interest of this study was to show that these signals can be used as a new source of data for CIT to image the ionosphere, possibly other data assimilation models, and to obtain a better understanding of magneto-ionic wave propagation.
        Speaker: Alex Cushley
      • 170
        SELF- AND AIR-BROADENED LINE SHAPE PARAMETERS OF METHANE IN THE 2.3 MICRONS RANGE
        Methane is an important greenhouse gas in the terrestrial atmosphere and a trace gas constituent in planetary atmospheres. We report measurements of the self- and air-broadened Lorentz widths, shifts and line mixing coefficients along with their temperature dependences for methane absorption lines in the 2.22 to 2.44 microns spectral range. This set of highly accurate spectral line shape parameters is needed for radiative transfer calculations in terrestrial or planetary atmospheres. This research was performed in collaboration with colleagues from the College of William and Mary, Williamsburg,VA, NASA Langley Research Center and Jet Propulsion Laboratory.
        Speaker: Adriana Predoi-Cross (University of Lethbridge)
        Slides
    • T1-4 Mathematical Physics (DTP) / Physique mathématique (DPT) CCIS L1-160

      CCIS L1-160

      University of Alberta

      Convener: Andrew Frey (University of Winnipeg)
      • 171
        Geometrization of N-Extended 1-Dimensional Supersymmetry Algebras
        The problem of classifying off-shell representations of the N-extended one-dimensional super Poincare algebra is closely related to the study of a class of decorated graphs known as Adinkras. We show that these combinatorial objects possess a form of emergent supergeometry: Adinkras are equivalent to very special super Riemann surfaces with divisors. The method of proof critically involves Grothendieck's theory of "dessins d'enfants", work of Cimasoni-Reshetikhin expressing spin structures on Riemann surfaces via dimer models, and an observation of Donagi-Witten on parabolic structure from ramified coverings of super Riemann surfaces.
        Speaker: Charles Doran (University of Alberta)
      • 172
        Some discrete-flavoured approaches to Dyson-Schwinger equations
        I will discuss two recent ideas on how to better understand the underlying structure of Dyson-Schwinger equations in quantum field theory. These approaches use primarily combinatorial tools; classes of rooted trees in the first case and chord diagrams in the second case. The mathematics is explicit and approachable.
        Speaker: Karen Yeats (Simon Fraser University)
        Slides
      • 173
        Novel Charges in CFT's
        In this talk we construct two infinite sets of self-adjoint commuting charges for a quite general CFT. They come out naturally by considering an infinite embedding chain of Lie algebras, an underlying structure that share all theories with gauge groups U(N), SO(N) and Sp(N). The generality of the construction allows us to carry all gauge groups at the same time in a unified framework, and so to understand the similarities among them. The eigenstates of these charges are restricted Schur polynomials and their eigenvalues encode the value of the correlators of two restricted Schurs. The existence of these charges singles out restricted Schur polynomials among the number of bases of orthogonal gauge invariant operators that are available in the literature.
        Speaker: Dr Pablo Diaz Benito (University of Lethbridge)
      • 174
        Yang-Mills Flow in the Abelian Higgs Model
        The Yang-Mills flow equations are a parabolic system of partial differential equations determined by the gradient of the Yang-Mills functional, whose stationary points are given by solutions to the equations of motion. We consider the flow equations for a Yang-Mills-Higgs system, where the gauge field is coupled with a scalar field. In particular we consider the Abelian case with axial symmetry. In this case we have vortex-type classical solutions corresponding to Ginzburg-Landau model of superconductivity. In this case the flow equations are reduced to two coupled partial differential equations in two variables, which we can solve numerically given initial conditions. Looking at the behaviour of the flow near the solutions in this model tells us about the stability of the solutions, and in the case of stable solutions allows us to approximate the solutions numerically. Study of the flow in the dimensionally reduced Abelian case provides a starting point for studying flows in more complicated cases, such as non-Abelian Higgs models, or full 3+1 dimensional theories. Using the AdS/CFT correspondence, which provides an equivalence between a field theory and a gravitational theory in one higher dimension where Yang-Mills flow could be compared with more well known geometric flow equations such as Ricci flow.
        Speaker: Paul Mikula (University of Manitoba)
        Slides
    • T1-5 Energy Frontier: Susy & Exotics I (PPD-DTP) / Frontière d'énergie: supersymétrie et particules exotiques I (PPD-DPT) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Reyhaneh Rezvani (Université de Montréal)
      • 175
        Natural and unnatural SUSY
        After the first run of LHC, the parameter space of supersymmetric theories is under serious pressure. In this talk I will present attempts at natural SUSY model building and also discuss the consequences of relaxing the naturalness assumption of supersymmetric theories.
        Speaker: Thomas Gregoire (Carleton University)
        Slides
      • 176
        Hunt for Supersymmetry with the ATLAS detector at LHC
        Supersymmetry is one of the most motivated theories beyond the Standard Model of particle physics. It explains the mass of the observed Higgs boson and provides a Dark Matter candidate among other attractive features. A striking prediction of Supersymmetry is the existence of a new particle for each Standard Model one. I will highlight results of the extensive program of the ATLAS Collaboration searching for supersymmetric particles with the Run 1 data of 2012 and show the discovery potential of Run 2 starting in the summer of 2015.
        Speaker: Zoltan Gecse (University of British Columbia (CA))
        Slides
      • 177
        A search for heavy gluon and vector-like quark in the 4b final state in pp collisions at 8 TeV
        Searches for vector-like quarks are motivated by Composite Higgs models assuming a new strong sector and predict the existence of new heavy resonances. A search for single production of vector-like quarks is performed for the through the exchange of a heavy gluon in the $p p \to G^* \to B\bar b/\bar B b \to H b \bar b \to b~\bar b~b~\bar b$ process, where $G^*$ is a heavy color octet vector resonance and $B$ a vector-like quark of charge -1/3. The largest background, QCD multi-jet, is estimated using a data-driven method. In case of no excess of events, upper limits on the production cross sections and lower limits in the 2D plane {m_G^*, m_B} will be set.
        Speaker: Frederick Dallaire (Universite de Montreal (CA))
        Slides
      • 178
        Electroweak Baryogenesis and the LHC
        It is not known how to explain the excess of matter over antimatter with the Standard Model. This matter asymmetry can be accounted for in certain extensions of the Standard Model through the mechanism of electroweak baryogenesis (EWBG), in which the extra baryons are created in the early Universe during the electroweak phase transition. In this talk I will review EWBG, connect it to theories of new physics beyond the Standard Model, and show that in many cases the new particles and interactions required for efficient EWBG can be discovered using existing and expected data from the LHC.
        Speaker: David Morrissey (TRIUMF)
        Slides
    • T1-6 Cosmic Frontier: Cosmology II (PPD-DTP-DIMP) / Frontière cosmique: cosmologie II (PPD-DPT-DPIM) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: Claudio Kopper (University of Alberta)
      • 179
        New results from Planck
        The Planck satellite has completed its mission to map the entire microwave sky at nine separate frequencies. A new data release was made in February 2015, based on the full mission, and including some polarization data for the first time. The Planck team has already produced more than 100 papers, covering many different aspects of the cosmic microwave background (CMB). We have been able to learn in detail about the physics of the interstellar medium in our Galaxy, and to remove this foreground emission in order to extract the cosmological information from the background radiation. Planck's measurements lead to an improved understanding of the basic model which describes the Universe on the very largest scales. In particular, a 6 parameter model fits the CMB data very well, with no strong evidence for extensions to that sceneraio. There are constraints on inflationary models, neutrino physics, dark energy and many other theoretical ideas. New cosmological probes include CMB lensing, CMB-extracted clusters of galaxies, the Cosmic Infrared Background and constraints on large-scale velocities. This talk will highlight some of the new results of the 2015 papers, including the improvements coming from the addition of polarization dimension.
        Speaker: Douglas Scott (UBC)
      • 180
        **WITHDRAWN** Planck, gravity waves, and cosmology in the 21st century
        In this talk I'll survey the current observational status in cosmology, highlighting recent developments such as results from the Planck satellite, and speculate on what we might achieve in the future. In the near future some important milestones will be exploration of the neutrino sector, and much better constraints on the physics of the early universe via B-mode polarization. In the far future we can hope to measure a variety of cosmological parameters to much higher precision than they are currently constrained.
        Speaker: Kendrick Smith (Perimeter Institute for Theoretical Physics)
      • 181
        The CHIME Dark Energy Project
        The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a novel radio telescope currently under construction at the Dominion Radio Astrophysical Observatory in Penticton, BC. Comprising four 20-m by 100-m parabolic cylinders, each equipped with 256 antennas along its focal line, CHIME is a `software telescope' with no moving parts. It will measure the 21-cm emission from neutral hydrogen to map the distribution of matter between redshifts 0.8 and 2.5, over most of the northern sky. By following the apparent size of the baryon acoustic oscillation (BAO) feature in the data, we can measure the expansion history of the Universe over an epoch where the effects of Dark Energy began to become important and thereby improve our understanding of this recently discovered phenomenon. The science goals, technical details, and current status of CHIME will be presented.
        Speaker: Prof. David Hanna (McGill University)
        Slides
    • T1-7 Nuclear Structure I (DNP) / Structure nucléaire I (DPN) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Adam Garnsworthy (TRIUMF)
      • 182
        Light Exotic Nuclei Studied via Resonance Scattering
        Remarkable advances have been made toward achieving the long-sought-after dream of describing properties of nuclei starting from realistic nucleon-nucleon interactions in the last two decades. The ab initio models were very successful in pushing the limits of their applicability toward nuclear systems with ever more nucleons and exotic neutron to proton ratios. Predictions of these models often are very close to the experimental data, but sometimes deviate from experiment substantially. For example, the exotic isotope of helium, $^9$He, represents a curious case of stark disagreement between the predictions of modern theories and what is believed to be the experimental knowledge of this nucleus. In this talk I will present recent experimental results that shed light on structure of $^9$He and some other light exotic nuclei that were studied using resonance scattering approach and will discuss these findings in view of predictions of the ab initio models.
        Speaker: Grigory Rogachev (Texas A&M University)
      • 183
        Low-energy, precision experiments with ion traps: mass measurements and decay spectroscopy
        The atomic mass is a unique identifier of each nuclide, akin to a human fingerprint, and manifests the sum of all interactions among its constituent particles. Hence it provides invaluable insights into many disciplines from forensics to metrology. At TRIUMF Ion Trap for Atomic and Nuclear science (TITAN), Penning trap mass spectrometry is performed on radioactive nuclides, particularly those with half-lives of as short as 9 ms. The TITAN mass values of Mg-20 and Mg-21 have been used to test the isobaric multiplet mass equation (IMME), revealing its dramatic breakdown. On the other side of the valley of stability, the increasingly detailed mass survey in the island of inversion on nuclides has exposed the lowest shell gap of any magic nucleus and the first crossover in the two-neutron separation energy. At heavier masses, neutron-rich Rb and Sr isotopes have been charge bred and their masses measured to probe the r-process, which is believed to be responsible for the production of roughly 50% of the abundance of elements heavier than Fe. A highlight of recent results and an overview of the advanced ion-manipulation techniques used will be presented.
        Speaker: Anna Kwiatkowski (TRIUMF)
      • 184
        Electric Monopole Transition Strengths in $^{62}$Ni
        Excited states in $^{62}$Ni were populated with a (p, p') reaction using the 14UD Pelletron accelerator at the Australian National University. The proton beam had an energy of 5 MeV and was incident upon a self-supporting $^{62}$Ni target of 1.2 mg/cm$^2$. Electric monopole transition strengths were measured from simultaneous detections of the internal conversion electrons and $\gamma$-rays emitted from the de-excitating states, using the Super-e spectrometer coupled with a Germanium detector. The Super-e spectrometer has a superconducting solenoid magnet with its magnetic axis arranged perpendicular to the beam axis, which transports the electrons from the target to the 9 mm thick Si(Li) detector array which is situated 350 mm away from the target. The strength of the $0_2^+ \rightarrow 0_1^+$ transition has been measured to be 77$^{+23}_{-34} \times 10^{-3}$ and agrees with previously reported values. Upper limits have been placed on the $0^+_3 \rightarrow 0^+_1$ and $0^+_3 \rightarrow 0^+_2$ transitions. The measured $\rho^2(E0)$ value of the $2^+_2 \rightarrow 2^+_1$ transition in $^{62}$Ni has been measured for the first time and found to be the largest $\rho^2(E0)$ value measured to date in nuclei heavier than Ca. The low-lying states of $^{62}$Ni have previously been classified as one- and two-phonon vibrational states based on level energies. The measured electric quadrupole transition strengths are consistent with this interpretation. However as electric monopole transitions are forbidden between states which differ by one phonon number, the simple harmonic quadrupole vibrational picture is not sufficient to explain the large $\rho^2 (E0)$ value for the $2^+_2 \rightarrow 2^+_1$ transition. A discussion of the results and experimental technique will be presented, along with preliminary shell model calculations.
        Speaker: Mr Lee J. Evitts (TRIUMF)
      • 185
        **WITHDRAWN** Fast-timing mesurements in neutron-rich $^{65}$Co
        The region below $^{68}$Ni has recently attracted great attention, from both experimental and theoretical studies, due to the observation of a sub-shell closure at N=40 and Z=28. The collectivity in the region is revealed in the even-even Fe and Cr isotopes by the low energy of the first 2$^+$ states and the enhanced $B(E2;2^+\rightarrow0^+)$ reduced transition probabilities, which peak at 21(5) W.u. for $^{64}$Cr[1], $^{66}$Fe[2] and 22(3) W.u. for $^{68}$Fe[1]. These effects can only be reproduced by large-scale shell model calculations with the inclusion of the $\nu g_{9/2}$ and $\nu d_{5/2}$ orbitals. Precise experimental information on the Co isotopes is important for understanding the nuclear structure in this region, with particular interest in the transition rates, as they can be interpreted as originating from a $\pi f^{-1}_{7/2}$ proton hole coupled to its even-even Ni neighbor. With this aim, a fast-timing ATD $\beta\gamma\gamma$(t) [3] experiment was performed at ISOLDE in CERN, where the $\beta$-decay chain of exotic neutron-rich Mn were measured. In this work we report on the investigation of the low-energy structure of $^{65}$Co populated in the $\beta$-decay of $^{65}$Fe by means of $\gamma\gamma$ and fast-timing spectroscopy. Our $^{65}$Co level scheme confirms the transitions previously observed in [4] and expands it with several new gammas and levels up to $\sim$2.5 MeV. Employing the ATD $\beta\gamma\gamma$(t) method, the half-lives and lifetime limits of some of the low-lying states have been measured for the first time. Some of the deduced transition rates are significantly lower than expected by the systematics of the region, yet this remains to be to be explained by shell model calculations. Making use of the measured half-lives, tentative spin-parities are proposed for some of the lower levels. [1] H.L. Crawford et al., Phys. Rev. Lett. 110, 242701 (2013). [2] W. Rother et al., Phys. Rev. Lett. 106, 022502 (2011). [3] H. Mach et al., Nucl. Instrum. Meth. A280, 49 (1989). [4] D. Pauwels et al. Phys. Rev. C 79, 044309 (2009).
        Speaker: Bruno Olaizola Mampaso (Nuclear Physics Group - University of Guelph)
    • T1-8 Special session to honor Dr. Akira Hirose I (DPP) / Session speciale en l'honneur de Dr. Akira Hirose I (DPP) CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Luc Stafford (U.Montréal)
      • 186
        Overview of the Recent J-TEXT Results
        The experimental research in recent years on the J-TEXT tokamak are summarized, the most significant results including observation of core magnetic and density perturbations associated with sawtooth events and tearing instabilities by a high-performance polarimeter-interferometer (POLARIS), investigation of a rotating helical magnetic field perturbation on tearing modes, studies of resonant magnetic perturbations (RMP) on plasma flows and fluctuations, and explorations of high density disruptions in ohmic heating and gas puffing discharges. The POLARIS system developed on J-TEXT has time response up to 1 μs, phase resolution < 0.1o and spatial resolution ~3 cm (17 chords). Such high resolution permits investigations of fast equilibrium dynamics as well as magnetic and density perturbations associated with magnetohydrodynamic (MHD) instabilities. Based on the measurement, temporal evolution of the safety factor profile, current density profile and electron density profile are obtained during sawtooth crash events as well as disruptions. In addition, core magnetic and density perturbations associated with MHD tearing instabilities are clearly detected. Particle transport due to the sawtooth crashes is analyzed. It found that the sawteeth only partially flatten the core density profile, but enhanced particle diffusion on the time scale of the thermal crash occurs over much of the profile. The RMP system on J-TEXT can generate a rotating helical field perturbation with a maximum rotation frequency up to 10 kHz, and dominant resonant modes of m/n = 2/1, 3/1 or 1/1. It is found that tearing modes can be easily locked and then rotate together with a rotating RMP. During the mode locking and unlocking, instead of amplifying the island, the RMP can suppress the island width, especially when there is a small frequency gap between the island and the RMP. The effects of RMPs on plasma flows and fluctuations are studied with Langmuir probe arrays at the plasma edge. Both toroidal rotation velocity and radial electric field increase with RMP coil current when the RMP current is no more than 5kA. When the RMP current reaches 6kA, the toroidal velocity profile becomes flatter near the last closed flux surface. The absolute amplitude of Er also significantly decreases at IRMP = 6 kA. At the same time, the behavior of the poloidal and toroidal turbulent stresses from simultaneous probe measurements are consistent with the Er trends. Both LFZF and GAM are also damped by strong RMPs. Some interesting features of high density disruptions are identified by interpreting the measured POLARIS data and the radiation power measurements. In the density ramp-up phase of a high density disruption shot, an asymmetry of density profile between the Low-Field-Side (LFS) edge (r>0.8a) and the High-Field-Side (HFS) edge (r<-0.8a) would appear and increase gradually. At the same time, an asymmetry of radiation power profile also arises as the result of the asymmetry of density profile at the edge. When the density at the HFS edge increases to nearly twice as large as the density at the LFS edge, a low-frequency (<1kHz) density perturbation suddenly stimulates at the HFS edge and gradually expanded into the center region. The disruption takes place when the density perturbation reaches the location nearly the q=2 surface. All the details will be presented at the meeting.
        Speaker: Ge Zhuang (Huazhong University of Science and Technology)
      • 187
        Magnetic Fluctuations Measurements in Magnetized Confinement Plasmas
        Both the magnetic fluctuations and electron density fluctuations are important parameters for fusion-oriented plasma research since fluctuation-driven transport dominates in high temperature magnetic confinement devices. The far-infrared laser systems are employed to measure both the Faraday rotation and electron density simultaneously with time response up to a few microseconds in reversed filed pinch, tokamaks. Fast time response combined with low phase noise also enables us to directly measure magnetic and density fluctuations. The various MHD activities such as sawtooth crash, tearing reconnection and fast particle modes have been observed in various magnetic confinement devices. The high temporal resolution of polarimetry provides excellent platform to study internal magnetic fluctuations and magnetic fluctuation induced transport. The work is supported by US Department of Energy.
        Speaker: Dr Weixing Ding (UCLA)
      • 188
        Plasma Ion Implantation for Photonic and Electronic Device Applications
        Plasma Ion Implantation (PII) is a versatile ion implantation technique which allows very high fluence ion implantation into a range of targets. The technique is conformal to the surface of the implanted object, which makes it suitable for a wide range of applications. The ease with which high ion fluences can be delivered means that the technique can be used to change the stoichiometry (e.g. elemental composition) as well as the atomic-level structure of the target material in the implanted region. When combined with masking techniques and post-implant thermal processing, PII offers a powerful way to make new materials in-situ (e.g. within an existing solid-state matrix). The Plasma Physics Lab (PPL) at the University of Saskatchewan is home to a custom PII system with ion implantation energies ranging from 0-20 keV. This system is capable of a delivering very high ion doses in short times (e.g. high ion fluences) and has been employed in a range of applications, primarily oriented toward applications in photonics, to modify the properties of a variety of semiconductor materials. It has been used to fabricate luminescent silicon Schottky diodes based on silicon nanocrystals as well as SiC nanocrystallites. A more recent, low energy application of the system is N-doping of graphene, a technologically important new material for future electronic and photonic applications.
        Speaker: Prof. Michael Bradley (Physics & Engineering Physics, University of Saskatchewan)
    • T1-9 Nanostructured Surfaces and Thin Films (DSS-DCMMP) / Surfaces et couches minces nanostructurées (DSS-DPMCM) CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Steve Patitsas (University of Lethbridge)
      • 189
        **WITHDRAWN** Electrical and optical properties of electrochromic Tungsten trioxide (WO3) thin films at temperature range 300 to 500K
        During the past decade a great interest has been shown in the study of transition tungsten trioxide (WO3) thin films. The reason is that this transition presents a number of interesting optical and electrical properties. While their optical properties are very well studied in view of their application in smart windows, not much study is focussed on their electrical properties as a function of temperature. In this work we will present a detailed study of the electrical properties of lithium intercalated as a function of the temperature coefficient of resistance (TCR) of WO3 thin films as well as the electrochromic properties of these films. Using the variable range hoping model we calculated the density of states at the Fermi level of a samples prepared by thermal evaporation and inserted with lithium by a dry process. The TCR measurements were performed in temperature range 300 to 500 K. The understanding of this temperature dependent electrical behavior is expected to enhance our understanding of the electrochromic process in these films.
        Speaker: Bassel Abdel Samad (Moncton University)
      • 190
        Characterization of the 2D percolation transition in ultrathin Fe/W(110) films using the magnetic susceptibility
        The growth of the first atomic layer of an ultrathin film begins with the deposition of isolated islands. Upon further deposition, the islands increase in size until, at some critical deposition, the merging of the islands creates at least one connected region of diverging size. This universal phenomenon describing connectivity is termed “percolation” and occurs at a “percolation transition” that can be described in renormalization group theory. In the context of a 2-dimensional ultrathin ferromagnetic film, geometric percolation can be monitored through the magnetic susceptibility, since as the island size diverges so does the correlation length of the ferromagnetic state. Although much work has been done studying films of known deposition as a function of temperature to detect percolation, very little work has characterized the transition as it occurs as a function of deposition at constant temperature. We report on measurements of the magnetic susceptibility, using the surface magneto-optic Kerr effect (SMOKE) under ultrahigh vacuum (UHV), as a function of deposition (at constant temperature) for the Fe/W(110) system as the first atomic layer is formed. Two regimes were detected: a high temperature regime with a broad susceptibility peak at larger depositions that represent a standard Curie transition from paramagnetism to ferromagnetism in a continuous film, and a low temperature regime with a much sharper peak in the susceptibility that occurs at the same deposition regardless of temperature. The low temperature regime is a good candidate for a geometric 2-dimensional percolation transition. Preliminary analysis gives a percolation critical exponent of $\gamma = 2.4 \pm 0.2$, in agreement with the result from the 2D Ising model.
        Speaker: Randy Belanger (McMaster University)
        Slides
      • 191
        You don't know what you've got 'till it's gone: ambient surface degradation of ZnO powders
        ZnO has rich electronic and optical properties that are influenced by surface structure and composition, which in turn are strongly affected by interactions with water and carbon dioxide. We correlated the effects of particle size, surface area, and crystal habit with data from X-ray photoelectron spectroscopy and zeta potential measurements to compare the degradation of ZnO powders prepared by several different synthesis methods. Neither surface polarity nor surface area, on their own, can account for the differences in the extent of carbonation among differently synthesized ZnO samples, and dissolution is a very significant in some samples [1]. Furthermore, ambient surface carbonation appears to be self-limiting for some ZnO powders (solvothermal synthesis), while ZnO produced by other synthesis methods (solid-state metathesis) can be completely converted to hydrozincite, Zn$_5$(OH)$_6$(CO$_3$)$_2$ in a matter of weeks. We show how these differences in surface carbonation correlate with frequency-dependent electrical properties, emphasizing the impact of ambient humidity variations. [1] J. Cheng and K.M. Poduska, ECS Journal of Solid State Science and Technology, 3 (5) P133-P137 (2014).
        Speaker: Kristin Poduska (Memorial University of Newfoundland)
      • 192
        **WITHDRAWN** Density Functional Theory Study of Hydrogen on Metal Oxide and Insulator Surfaces
        Hydrogen molecule is being promoted as an environmentally clean energy source of the future. In order to use hydrogen as a source of energy, infrastructures have to be built. These infrastructures are efficient processes for hydrogen extraction, and efficient processes and materials for hydrogen storage. The major problem facing the use of hydrogen as a clean source of energy is the storage of liquid hydrogen. Hydrogen fuel can be concentrated into a small volume and store it in fuel tanks. The concentration of hydrogen can be done simply by cooling the hydrogen to an extremely low temperature or by compressing it under very high pressure as liquid. The concentrated normal mixture consist 25% *p*-H2, 75 % *o*-H2 and after hours of storage, about 40 % of the original content of the tank evaporates. The reason of this evaporation is the spontaneous conversion of orthohydrogen (*o*-H2) to parahydrogen (*p*-H2) over a period of time. This conversion is releasing enough heat to evaporate most of the liquid hydrogen and yield the explosion of the tank storage. In order to overcome this problem and limit the boil-off to low levels, the tank most be fill with a liquid hydrogen that has already been converted to a mixture close to 100 % *p*-H2. Special procedures are needed to maintain the composition (proportion) of the two types of hydrogen molecules (*o*-H2) and parahydrogen (*p*-H2) to be 100 % *p*-H2. In this presentation we will discuss the results of DFT methods of hydrogen molecule physisorbed on SrTiO3, Fe(OH)3 and MgO(001) surfaces. Energies, orbitals, positions and vibration frequencies of H2 molecule on these surfaces are calculated. Our results show that H2 molecules can physisorbed on these surfaces and that these surfaces induce o–p conversation of H2. The effect of molecular orientations and positions of H2 molecules on the catalysts surface on the *o-p* H2 conversion yield will be presented.
        Speaker: Prof. Abdulwahab Sallabi (Physics Department, Misurata University, Misurata , Libya)
    • CAP Foundation Board Meeting / Réunion du CA de la Fondation de l'ACP CCIS 4-285

      CCIS 4-285

      University of Alberta

      Convener: Robert Mann (University of Waterloo)
    • T-MEDAL CAP Medal Talk - Chitra Rangan, U. Windsor (Teaching Undergraduate Physics / Enseignement de la physique au 1er cycle) CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Adam Sarty (Saint Mary's University)
      • 193
        Generating Ideas for Active and Experiential Learning in Physics
        The Physics community has known the importance of Active Learning (AL) for the last twenty years (see [1,2]). A recent analysis of 225 studies on AL [3] has demonstrated that “active learning appears effective across all class sizes --- although the greatest effects are in small (n <= 50) classes.” Physicists have innovated both technologies and techniques for AL [4,5]. Yet, most classes, particularly in institutions where research is conducted, are primarily delivered via lectures. Many research-active faculty members do not feel like they have the time or incentive to explore AL methodologies. At the University of Windsor, we have started a Faculty Network called “Promoters of Experiential, Active, and Research-based Learning” [6] to support our teacher-researcher colleagues in the Faculty of Science. Inspired by the activities of this network, in this session, I will lead a discussion on how very busy, teacher-researchers can adopt proven Active Learning strategies in their own classes. [1] Richard Hake, “Interactive-engagement vs. traditional methods: A six-thousand-student survey of mechanics test data for introductory physics courses” American Journal of Physics, v. 66, pp. 64-74 (1998). [2] Deslauriers, L., E. Schelew, and C. Wieman, "Improved Learning in a Large-Enrollment Physics Class" Science, v. 332, pp. 862-864 (2011). [3] Scott Freeman et al., “Active learning increases student performance in science, engineering, and mathematics” PNAS, v.111, pp. 8410–8415 (2014). [4] David E. Meltzer and Ronald K. Thornton, "Resource Letter ALIP–1: Active-Learning Instruction in Physics" Am. J. Phys. v. 80, pp. 478 -496 (2012). [5] Multimedia Educational Resource for Learning and Online Teaching, http://www.merlot.org, © 1997–2015 MERLOT. Retrieved May 2, 2015. [6] P.E.A.R.L. @ UWindsor, www.uwindsor.ca/pearl.
        Speaker: Chitra Rangan (University of Windsor)
        Slides
    • Health Break (with exhibitors) / Pause santé (avec exposants) CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • Teachers' Day - Session II / Journée des enseignants - Atelier II CCIS L1-047

      CCIS L1-047

      University of Alberta

      • 194
        Quantum superposition and the uncertainty principle in the class room; a hands-on experience, Martin laforest, Senior manager, Scientific Outreach, Institute for Quantum Computing, University of Waterloo
    • NSERC Presentation by Elizabeth Boston / Présentation du CRSNG par Elizabeth Boston CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Robert Fedosejevs (University of Alberta)
    • NSERC EG Chair Report (L.-H. Xu) / Rapport de la présidente du GE (L.-H. Xu) CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Donna Strickland (University of Waterloo)
    • CAP-NSERC Liaison Committee Report (W. Whelan) / Rapport du Comité de liaison ACP-CRSNG (W. Whelan) CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Donna Strickland (University of Waterloo)
    • CAP Past Presidents' Meeting / Réunion des anciens présidents de l'ACP CCIS 4-285

      CCIS 4-285

      University of Alberta

      Convener: Ken Ragan (McGill)
    • DAMOPC Annual Meeting / Assemblée annuelle DPAMC CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Chitra Rangan (U)
    • DMBP Annual Meeting / Assemblée annuelle DPMB CAB 239

      CAB 239

      University of Alberta

      Convener: Maikel Rheinstadter (McMaster University)
    • DNP Annual Meeting / Assemblée annuelle DPN CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Zisis Papandreou (University of Regina)
    • DPP Annual Meeting / Assemblée annuelle DPP CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Chijin Xiao (Univ. of Saskatchewan)
    • IPP Scientific Council Meeting / Réunion du comité scientifique de l'IPP CCIS 2-122

      CCIS 2-122

      University of Alberta

      Convener: Michael Roney (University of Victoria)
    • Lunch / Dîner
    • New Faculty Lunch Meeting with NSERC / Dîner-rencontre des nouveaux professeurs avec le CRSNG CCIS L1-029

      CCIS L1-029

      University of Alberta

    • Teachers' Day - Lunch / Journée des enseignants - Diner CCIS L2 Teaching Labs

      CCIS L2 Teaching Labs

      University of Alberta

      • 195
        Afternoon workshops:
        List of proposed workshops, teachers will be asked to sign up for three workshop at most. A separate registration form for workshops will be sent to the teachers by the teachers local committee. - Cavendish experiment (measuring G) - Millikan oil drop. (obtaining the basic electron charge) - e/m for electrons. - Electron diffraction (verifying particle wave duality). - Video analysis of Galileo's ramp. - Frank-Hertz experiment (quantization of energy). - Faraday's rotation (polarization, field induced polarization). - Visit to Dr. Jacob's lab.
    • T2-1 Materials characterization: microscopy, imagining, spectroscopy (DCMMP) / Caractérisation des matériaux: microscopie, imagerie, spectroscopie (DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Eundeok Mun (Simon Fraser University)
      • 196
        Ultrafast Transmission Electron Microscopy and its Nanoplasmonic Applications
        Understanding matter at the dynamic and microscopic levels is fundamental for our ability to predict, control and ultimately design new functional properties for emerging technologies. Reaching such an understanding, however, has traditionally been difficult due to limited experimental methodologies that can simultaneously image both in space and time. Ultrafast transmission electron microscopy (UTEM), a newly emerging field, offers the means to overcome this limitation by merging the femtosecond domain of pulsed lasers with the nanoscale domain of transmission electron microscopes. With UTEM, it is possible to capture ultrafast events in real space, diffraction and even spectroscopy. In this particular contribution, we emphasize the plasmonic imaging capability of UTEM in space and time. Localized electric fields that are induced optically exhibit unique phenomena of fundamental importance to nanoplasmonics. UTEM enables direct visualization of these fields as they rise and fall within the duration of the excitation laser pulse (few hundreds of femtoseconds) with several nanometers of spatial resolution. This imaging approach is based on an inelastic photon-electron interaction process, where the probing electrons gain energy equal to the integer multiple of the photon quanta (2.4 eV in these experiments). This new phenomenon in electron energy loss spectroscopy and its fundamentals will be discussed. Furthermore, images, and movies, of plasmonic near-fields of particle dimers, nanoparticles with different sizes and shapes, particle ensembles and standing-wave plasmons at the step edges of layered-graphene strips are presented. These results establish UTEM as a tool with unique capabilities to approach nanoplasmonics.
        Speaker: Prof. Aycan Yurtsever (INRS-EMT)
      • 197
        Means of mitigating the limits to characterization of radiation sensitive samples in an electron microscope.
        The scattering of the fast electrons by a sample in the transmission electron microscope (TEM) results in a measurable signal and also leads to sample damage. In an extreme case, the damage can be severe and can proceed faster than data can be collected. The fundamental limit on whether a measurement can be performed is set by the interaction cross section and collection efficiency for the desired signal and by the total damage cross section. Mitigation strategies involve selecting the strongest possible signal, modifying the microscope optics and hardware to maximize the collection efficiency and preparing the sample in a way that maximizes the signal. A major recent breakthrough is the practical implementation of Zernike-like imaging in a TEM. The Zernike-like imaging in a TEM increases the contrast by a factor of two to four compared to conventional bright field TEM. The corresponding decrease in the irradiation dose needed to obtain desired signal to noise ratio translates either to higher resolution in the images or less damage to the sample at the same resolution. The mechanism utilized in this case is the local charging of an uniform thin film placed in the back focal plane of the objective lens of a TEM. The application of the Zernike-like imaging in TEM range from imaging of magnetic fields in vacuum to imaging of DNA strands.
        Speaker: Marek Malac
      • 198
        Terahertz Scanning Tunneling Microscopy in Ultrahigh Vacuum
        The terahertz scanning tunneling microscope (THz-STM) is a new imaging and spectroscopy tool that is capable of measuring picosecond electron dynamics at the nanoscale. Free-space THz pulses are commonly used for non-contact conductivity measurements, but they are diffraction limited to millimeter length scales. We can overcome this limit by coupling THz pulses to a sharp metal tip through propagating surface modes. At the STM junction, the THz pulse acts as a picosecond voltage transient which drives electron tunneling on an ultrafast timescale. This effect can be used to spatially and temporally probe the local conductivity of a surface after an excitation. Here we demonstrate THz-STM in an ultrahigh vacuum (UHV) environment for the first time. We have measured a THz-induced-tunnel-current over highly-oriented pyrolytic graphite (HOPG), and Si(111) in UHV. The experimental results agree well with our model, providing insight for the THz-STM mechanism. Recent progress towards atomic resolution and the nature of THz-induced-tunneling in an STM will be presented.
        Speaker: Mr Vedran Jelic (University of Alberta)
      • 199
        Identifying differences in long-range structural disorder in solids using mid-infrared spectroscopy
        Structural disorder in calcium carbonate materials is a topic of intense current interest in the fields of biomineralization, archaeological science, and geochemistry. In these fields, Fourier transform infrared (FTIR) spectroscopy is a standard material characterization tool because it can clearly distinguish between amorphous calcium carbonate and calcite. Earlier theoretical work based on density functional theory (DFT) showed that calcite's in-plane bending mode in FTIR is very sensitive to changes in local (intra-unit-cell) disorder, which accounts for the near vanishing amplitude of this peak for amorphous calcium carbonate [1]. In a subsequent study of polycrystalline calcites, DFT investigations showed that local disorder was also qualitatively consistent with changes in the in-plane bending modes for these materials [2]. Here, we examine this assumption by presenting our study of the structural differences among several different sources of crystalline calcite, all of which show differences in the widths of their FTIR in-plane bending mode peaks. We used X-ray diffraction (XRD) to assess disruptions to long-range periodicity including lattice strain, microstrain fluctuations, and crystalline domain size (crystallinity). These quantities were then correlated with mid-FTIR (carbonate vibrational mode) peak positions, widths and relative intensities. Unlike the earlier studies [2], our results show that the in-plane bending mode can be strongly affected by the long-range disorder (based on XRD data) even when the local environments (based on Extended X-ray Absorption Fine Structure data) are identical. This apparent discrepancy between calculated and experimental models of structural disorder is, in fact, strong evidence for the near continuum of local and long-range structural differences that calcium carbonate materials can accommodate. Thus, we conclude that mid-FTIR spectra can be a powerful diagnostic for identifying differences in long-range structural disorder in carbonate-containing materials. References: [1] R. Gueta, A. Natan, L. Addadi, S. Weiner, K. Refson and L. Kronik, Angew. Chem., Int. Ed., 2007, 46, 291–294. [2] K. M. Poduska, L. Regev, E. Boaretto, L. Addadi, S. Weiner, L. Kronik and S. Curtarolo, Adv. Mater., 2011, 23, 550–554.
        Speaker: Ben Xu (Memorial University)
    • T2-10 Cold and trapped atoms, molecules and ions (DAMOPC) / Atomes, molécules et ions froids et piégés (DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Chitra Rangan (University of Windsor)
      • 200
        Project ALPHA: Applying AMO Physics to Antimatter and Using Antimatter to Study AMO Physics
        In 2010, the ALPHA Collaboration working at the AD Facility at CERN achieved the first capture and storage of atomic antimatter with our confinement of low temperature antihydrogen in an Ioffe-type magnetic minimum atom trap. [1] This achievement was only reached through the application of a range of tools and techniques from an interdisciplinary spectrum of fields, including AMO Physics. Examples of AMO Physics tools used in antihydrogen capture and storage include charged particle confinement and manipulation in a Penning-Malmberg trap, evaporative cooling [2], and sympathetic (i.e. charged particle collisional) processes. With the achievement of stable and long-term storage of antihydrogen, focus at ALPHA has now shifted to using antihydrogen as a system for carrying out a range of atomic physics studies, including completion of proof of principle microwave spectroscopy [3], charge neutrality, and gravitational force measurements. With the completion of commissioning of our 2nd-geenration ALPHA-2 apparatus, we now aim to move into the field of high precision spectroscopy of antihydrogen. This invited talk will focus on discussing the AMO physics aspects of the ALPHA experiment, both the tools from AMO physics used for ALPHA and the AMO physics measurements undertaken and planned for ALPHA. This will include both work completed with the ALPHA-1 apparatus, and that undertaken and planned with the ALPHA-2 system. * Presented on behalf of the ALPHA Collaboration, CERN (http://alpha.web.cern.ch/). [1] G.B. Andresen et al. (ALPHA Collaboration), Nature Physics 7, 558 (2011). [2] G.B. Andresen et al. (ALPHA Collaboration, Phys. Rev. Lett. 105, 013003 (2010). [3] C. Amole et al. (ALPHA Collaboration), Nature 483, 439 (2012).
        Speaker: Prof. Robert Thompson (University of Calgary)
      • 201
        Evaporative Cooling in Electromagnetic Radio Frequency Ion Traps
        In 2011, the ALPHA collaboration created and trapped neutral anti-hydrogen particles for the first time in history [1]. Key to this achievement was the demonstration of evaporative cooling of charged particles in a Penning Trap, a cooling method that had not previously been achieved with trapped low temperature ions [2]. Work is currently underway at the University of Calgary to computationally investigate the feasibility of optimum conditions for employing evaporative cooling in Paul-type ion traps, a combination of cooling and trapping that has not been used in the past. Due to the complex ion-ion and ion-trapping field interactions, the system is modelled and equations of motion of particles solved computationally using the RK4 method. This work explored the intrinsic challenges of cooling a system of charged particles constrained by an oscillating field, and showing that, dependent on the precise system parameters, evaporation of particles from a trapped system may or may not reduce the temperature of the remainder of the ensemble. Therefore, an extensive range of simulations have been used to study the evolution of a system of ions trapped in an electromagnetic RF trap under a range of different initial conditions and plasma shapes. For each set of system parameters, the cooling parameters were varied using a Monte-Carlo method to find optimum conditions to achieve evaporative cooling, i.e achieving the highest temperature drop while minimizing the particle loss rate. This presentation will include the results of the work and it’s future applications in fields such as spectroscopy and mass measurements will be discussed. [1] G. B. Anderson et al. (ALPHA Collaboration), Nat. Phys., 558, (2011) [2] G. B. Anderson et al. (ALPHA Collaboration), Phys. Rev. Lett. 105, 013003 (2010)
        Speaker: Lohrasp Seify (University of Calgary)
      • 202
        Demonstration of a Microtrap Array and manipulation of Array Elements
        A novel magnetic microtrap has been demonstrated for ultracold neutral atoms [1]. It consists of two concentric currents loops having radii r1 and r2. A magnetic field minimum is generated along the axis of the loops if oppositely oriented currents flow through the loops. Selecting r2/r1 = 2.2 maximizes the restoring force to the trap center. The strength and position of the microtrap relative to the atom chip surface can be precisely adjusted by applying an external bias magnetic field. A microtrap array can be formed by linking individual microtraps in series. A linear array of 11 microtraps having r1= 60 microns, was loaded with more than 105 87Rb atoms using three different methods: 1) from a transported quadrupole magnetic trap, 2) directly from a mirror MOT and 3) from an optical dipole trap. A proposal to manipulate atoms in adjacent microtraps will also be presented. 1. B. Jian & W. A. van Wijngaarden, Appl. Physics B: Lasers & Optics. (2014).
        Speaker: Dr Bin Jian (National Research Council)
        Slides
      • 203
        Engineered spin-orbit coupling in ultracold quantum gases
        Ultracold quantum gases are an ideal medium with which to explore the many-body behaviour of quantum systems. With a century of research in atomic physics at the foundation, a wide variety of techniques are available for manipulating the parameters that govern the behaviour of these systems, including tuning the interactions between particles and manipulating their potential energy landscapes. In recent years, the ability to generate “artificial gauge fields” has made it possible to simulate, experimentally, the effects of electromagnetic fields among these uncharged particles. Using the same techniques, which selectively transfer momentum from light to atoms, a correlation between the internal state and the motion of the atoms, known as “spin-orbit coupling,” has also be realised in several quantum gas systems. The relationship between spin and motion is quite general: experiments in quantum gases have used it to perform experiments that mimic both Dirac equation (with high-energy phenomena) and the spintronics (with small power consumption). One promising avenue for quantum simulations with spin-orbit coupled systems is to study the competing effects of this coupling and interparticle interactions. To do this, potassium-39 systems are well-suited: they have widely tunable interactions and technically feasible spin-orbit coupling schemes. Unlike conventional solid state systems, both interactions and spin-orbit coupling are tunable, and predictions suggest that the character of the low-temperature ordered systems will depend strongly on these parameters, giving states that have both superfluid and magnetic character. Further, these experiments will allow for the study of non-equilibrium behaviour of the interacting, spin-orbit coupled system, including measuring behaviour at the condensation transition and low-temperature dynamics.
        Speaker: Lindsay LeBlanc (University of Alberta)
    • T2-11 Laser, Laser-matter interactions, and plasma based applications (DPP) / Lasers, interactions laser-matière et applications basées sur les plasmas (DPP) CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Andranik Sarkissian (PLASMIONIQUE Inc)
      • 204
        Modification of graphene films in the flowing afterglow of microwave plasmas at reduced-pressure
        Graphene films were exposed to the late afterglow of a reduced-pressure N2 plasma sustained by microwave electromagnetic fields. X-ray photoelectron spectroscopy (XPS) shows that plasma-generated N atoms are incorporated into both pyridinic and pyrrolic groups, without excessive reduction of sp2 bonding. Nitrogen incorporation was found to be preceded by N adsorption, where N adatom density increased linearly with treatment time while aromatic nitrogen saturated. This finding was confirmed by Raman spectra showing a linear increase of the D:G ratio attributed to constant surface flux of plasma generated species. Combined Density Functional Theory calculations with a Nudged Elastic Band (DFT-NEB) approach indicate that incorporation reactions taking place at point vacancies in the graphene lattice requires an activation energy in the 2-6 eV range, but the energy required for the reverse reaction exceeds 8 eV. Stable nitrogen incorporation is therefore judged to be defect-localized and dependent on the energy transfer (6 eV) provided by N2(A)-to-N2(X) metastable-to-ground de-excitation reactions occurring at the late-afterglow-graphene interface. This represents one of the first experimental evidence of the role of metastables during materials and nanomaterials processing in non-thermal plasmas.
        Speaker: Luc Stafford (U.Montréal)
      • 205
        Pump-probe Studies of Warm Dense Matter
        Warm Dense Matter (WDM) is a material under extreme conditions which has near solid density but has a temperature of several electron volts. It is a state lies in between condense matter state and plasma state. The study of materials under extreme conditions is currently a forefront area of study in material science and has generated enormous scientific interest. The understanding of WDM is important for laser material processing, which has many scientific and industrial applications, as well as Inertial Fusion Energy, which is a safe energy source that has no carbon emission and almost unlimited fuel supply. The understanding of WDM is also important for planetary science and astrophysics. Ultrafast pump-probe methods can been used to study the evolution of WDM in sub-picosecond time scale. When a high intensity ultrashort laser pulse is absorbed by a solid target, a non-equilibrium WDM with electron temperature of several electron volts, ion temperature near room temperature and density remains as solid is formed initially in less than a picosecond. During the subsequent several picoseconds the electron temperature reduces and ion temperature rises and target eventually disassembles into an expanding plasma. Ultrafast probing techniques based on optical, electron diffraction and x-ray diffraction have been used to study the properties of laser produced WDM led to a better understanding of WDM. An overview of our current understanding of laser produced WDM will be presented in this talk.
        Speaker: Prof. Ying Tsui (University of Alberta)
      • 206
        Deposition of functional coatings on glass substrates using a recently-developed atmospheric-pressure microwave plasma jet
        In recent years, atmospheric-pressure plasmas have gained a lot of interest in view of their interest for fast treatment of materials over large area wafers. While such plasmas are typically based on corona or dielectric barrier discharges (DBDs) for processing of thin samples (for example roll-to-roll systems), a number of applications require the treatment of thicker samples and thus the use of plasma jet configurations. We have recently developed a new, atmospheric-pressure plasma source using a surfaguide sustaining simultaneously 3 tubular plasmas based on the propagation of an electromagnetic surface wave. Operated at 2.45GHz, these tubular plasmas are characterized by much higher electron densities (10^13-10^14cm-3) than conventional DBDs (10^9-10^10 cm-3), thus allowing very high fragmentation rates of precursors intended for PECVD, even in a jet configuration. In the waveguide system used in this study, since only the fundamental mode (a cosine maximum of the electric field on the axis of the large section of the rectangular waveguide) is propagating, the first two tubes were placed off-axis, while the last one was placed just after, on the axis. Such configuration enabled important power absorption by the latter tube even if significant amount of power was already used by the first two. Through the displacement of a plunger located at the end of the transmission line, after the surfaguide, selective lengths of the first-row tubes and second-row tube can be achieved. This phenomenon is ascribed to the displacement of the maximum electric field intensity of an established stationary wave in the transmission line. For short tube lengths downward of the surfaguide, a peculiar spatial structure was observed in which off-axis plasma filaments close to the wave launcher converged towards a single on-axis point near the exit followed by a diffuse plasma plume.
        Speaker: Mr Antoine Durocher-Jean (U. Montreal)
      • 207
        Measurements of Ionization States in Warm Dense Aluminum with Femtosecond Betatron Radiation from a Laser Wakefield Accelerator
        Study of the ionization state of material in the warm dense matter regime is a significant challenge at present. Recently, we have demonstrated that the femtosecond duration Betatron x-ray radiation from the laser wakefield acceleration of electrons is capable of being employed as a probe to directly measure the ionization states of warm dense aluminum via K-shell line absorption spectroscopy [1]. In order to apply the radiation for such an application, a Kirkpatrick-Baez Microscope is used to selectively focus the radiation around the 1.5 keV photon energy range onto a 50-nm free-standing aluminum foil that is heated by a synchronized 800 nm laser pump pulse. The transmitted x-ray spectrum is spectrally resolved by a flat Potassium Acid Phthalate (KAP) Bragg crystal spectrometer. Here we report the results of the first-time direct measurements of the ionization states of warm dense aluminum using this Betatron x-ray probe setup. Measurements of the ionization states were taken at two pump fluences and various time delays to observe the evolution of the warm dense matter state. Plasmas spectroscopic modeling associated with 1D hydrodynamic simulation is being carried out to interpret the ionized charge distributions from the measured K-shell absorption lines. Details of the measurements and simulations will be presented. [1] M.Z. Mo, et al., Rev. Sci. Instrum. 84, 123106 (2013).
        Speaker: Mianzhen Mo (University of Alberta)
        Slides
    • T2-2 Condensed Matter Theory (DCMMP-DTP) / Théorie de la matière condensée (DPMCM-DPT) CAB 235

      CAB 235

      University of Alberta

      Convener: Joseph Maciejko (University of Alberta)
      • 208
        Many-body localization and potential realizations in cold atomic gases
        Disorder in a non-interacting quantum system can lead to Anderson localization where single-particle wave functions become localized in some region of space. Recently, the study of interaction effects in systems which do exhibit Anderson localization has attracted renewed interest. In my talk I will present recent theorerical progress in understanding localization in many-body systems. I will, in particular, discuss one-dimensional lattice models with binary disorder which can potentially be realized in cold atomic gases using two species of atoms. A purification scheme can be used to perform an exact binary disorder average making such models amenable to numerical studies directly in the thermodynamic limit.
        Speaker: Jesko Sirker (U Manitoba)
      • 209
        Light-Trapping Architecture for Room Temperature Bose-Einstein Condensation of Exciton-Polaritons near Telecommunication Frequencies
        While normally quantum mechanical effects are observable at cryogenic temperatures and at very small length scales, our work brings these quantum phenomena to the macroscopic length scale and to room temperature. Our work focuses on the possibility of room-temperature thermal equilibrium Bose-Einstein condensation (BEC) of quantum well exciton-polaritons in micrometer scale cavities composed of photonic band gap materials. Using cavities composed of double slanted pore (SP2) photonic crystals embedded with InGaAs quantum wells, we predict the formation of a 10 $\mu$m to 1 cm sized thermal equilibrium Bose-Einstein condensate at room temperature that allows for the emission of light near the telecommunications band of $\sim$1300 nm. The three-dimensional photonic band gap of the SP2 crystal allows for light to be strongly confined to the quantum wells, resulting in strong light-matter coupling in the exciton-polaritons and vacuum Rabi splittings that are $\sim$2% of the bare exciton recombination energy. The photonic band gap also strongly inhibits the radiative decay of the exciton-polaritons and due to the slow non-radiative decay of excitons as well as fast exciton-phonon scattering in InGaAs at room temperature, the exciton-polaritons that form the BEC are able to reach thermal equilibrium with their host lattice. We consider three InGaAs quantum wells (of width 3 nm surrounded by 7 nm InP barriers) judiciously placed in a 33 nm cavity between SP2 crystals with a lattice constant of 471 nm and polaritons consisting of a superposition of excitons and photons that are tuned below the excitonic recombination energy. This detuning increases the polariton's dispersion depth and increases the number of available photon-like states to enhance the formation of a BEC. We predict the onset of a BEC at a temperature of 364 K in a box-trap of side length 10 $\mu$m at a polariton density of $1.6\times10^{11}$ cm$^{-2}$, indicating that a room temperature, thermal equilibrium BEC can be obtained with light emission near the telecommunications band.
        Speaker: Mr Pranai Vasudev (University of Toronto)
      • 210
        Molecular-dynamics simulations of two-dimensional Si nanostructures
        Nanostructed materials make it possible to tailor the vibrational properties of a system for specific uses like thermoelectric applications or phononic waveguides. In this work, the vibrational properties of two-dimensional silicon nanostructures are studied. The nanostructures are build from arrays of nanowires that are arranged in such a manner that they form a periodic lattice. The method of molecular-dynamics simulations is used to calculate the vibrational properties. Results will be shown for the vibrational density of states as well as dispersion relations at long wavelength.
        Speaker: Dr Ralf Meyer (Laurentian University)
      • 211
        Inverse melting in a simple 2D liquid
        We employ several computer simulation techniques to study the phase behaviour of a simple, two dimensional monodisperse system of particles interacting through a core-softened potential comprising a repulsive shoulder and an attractive square well. This model was previously constructed and used to explore anomalous liquid behaviour in 2D and 3D, including liquid-liquid phase separation [1]. The calculated phase diagram includes six crystal phases in addition to the liquid and gas. Interestingly, we find that one of the melting curves exhibits inverse melting, for which the liquid freezes to a crystal upon isobaric heating over a very small range of pressure [2]. We find that the range of inverse melting can be enlarged by increasing the extent of the repulsive shoulder, and show that despite occurring in 2D, the melting transition is first order and to a liquid, rather than to a hexatic or quasicrystal phase [3]. As this range increases, the topology of the phase diagram changes systematically until it breaks, leading to even more crystal phases appearing. [1] A. Scala, M. R. Sadr-Lahijany, N. Giovambattista, S. V. Buldyrev, and H. E. Stanley, Phys. Rev. E 63, 041202 (2001). [2] A. M. Almudallal, S. V. Buldyrev, and I. Saika-Voivod, J. Chem. Phys. 137, 034507 (2012). [3] A. M. Almudallal, S. V. Buldyrev, and I. Saika-Voivod, J. Chem. Phys. 140, 144505 (2014).
        Speaker: Ahmad Almudallal (Memorial University of Newfoundland)
      • 212
        Cellular Automaton with nonlinear Viscoelastic Stress Transfer to Model Earthquake Dynamics
        Earthquakes may be seen as an example of self-organized criticality. When we transform the Gutenberg-Richter law of earthquake magnitude, the seismic moment, as a measure of the energy released, yields a power law distribution indicating a self-similar pattern. The earthquake dynamics can be modelled by employing the spring-block system, which features a slowly-driving force, failure threshold and interactions between elements as in a complex system. In this approach the earthquake fault is modelled by an array of blocks coupling the loading plate and the lower plate. For computational simplicity, the spring-block model has been mapped to various cellular automata. However, the spring-block model (including the cellular automata version) with its underlying physics, is not sufficient to reproduce some of the empirical scaling laws for real seismicity. In particular, a robust power law time-dependence of the aftershock rate function can not be observed, which indicates the need to introduce new physical mechanisms for the aftershock triggering. Taking into account the rheology of the fault zone, we introduce the nonlinear viscoelastic stress transfer into the interactions between blocks and the tectonic loading force in a basic spring-block model setting. The shear stress of the viscous component is a power-law function of the velocity gradient with an exponent between 0 and 1, showing a shear weakening effect. As a result, the stress transfer function takes a power-law time-dependent form. It features an instantaneous stress transfer during an instantaneous avalanche triggered by the global loading, as well as a power-law relaxation term, which could trigger further aftershocks. In this nonlinear viscoelastic model, avalanches (earthquakes) triggered either by the global loading or the relaxation exhibit a robust power-law frequency-size distribution. Maximum-likelihood fitting of temporal rates of stacked sequences shows a power-law time decay, which agrees with the modified Omori law. Our results also show that the nonlinearity of the viscoelastic interactions plays a key role in determining the type of the stress transfer function. Our study suggests that the nonlinear viscoelastic stress transfer might be a possible triggering mechanism for real aftershocks.
        Speaker: Xiaoming Zhang (University of Western Ontario)
    • T2-3 Ground-based / in situ observations and studies of space environment II (DASP) / Observations et études de l'environnement spatial, sur terre et in situ II (DPAE) CAB 243

      CAB 243

      University of Alberta

      Convener: Donald Danskin (Natural Resources Canada)
      • 213
        New View of Aurora from Space using the e-POP Fast Auroral Imager
        The Fast Auroral Imager (FAI) on the CASSIOPE Enhanced Outflow Probe (e-POP) consists of two CCD cameras, which measure the atomic oxygen emission at 630 nm and prompt auroral emissions in the 650 to 1100 nm range, respectively, using a fast lens system and high quantum-efficiency CCDs to achieve high sensitivity, and a common 26 degree field-of-view to provide nighttime images of about 650 km diameter from apogee (1500 km). The FAI is capable of operating in four viewing modes: nadir viewing, for imaging over a large latitude range; Earth-target viewing, for pointing at an emission target of fixed altitude, latitude and longitude; limb viewing, for measurement of altitude profiles; and inertial pointing, for imaging of an inertial target such as a star field. The near infrared camera provides one image of 0.1 sec exposure per second, and we restrict our examples to this camera. The four viewing modes make possible the observations of a variety of auroral and airglow phenomena, such as rapidly varying and small-scale structures in the auroral oval. The examples shown here illustrate some obvious features in the auroral phenomena that lead to new perspectives in the context of high-resolution studies of ionospheric processes.
        Speaker: Prof. Leroy Cogger (University of Calgary)
        Slides
      • 214
        CASSIOPE e-POP and coordinated ground-based studies of polar ion outflow, auroral dynamics, wave-particle interactions, and radio propagation
        The Enhanced Polar Outflow Probe (e-POP) is an 8-instrument scientific payload on the Canadian CASSIOPE small satellite, comprised of plasma, magnetic field, radio, and optical instruments designed for in-situ observations in the topside polar ionosphere at the highest-possible resolution. Its science objectives are to quantify the micro-scale characteristics of plasma outflow in the polar ionosphere and probe related micro- and meso-scale plasma processes at unprecedented resolution, and explore the occurrence morphology of neutral escape in the upper atmosphere. The e-POP mission comprises three important components for the investigation of atmospheric and plasma flows and related auroral and wave particle interaction processes in the topside polar ionosphere: a satellite, a ground-based and a theoretical component. We present an overview of the important, new observations and related results from these three interconnected mission components since the successful launch of CASSIOPE in September 2013.
        Speaker: Andrew Yau (University of Calgary)
      • 215
        The nature of GPS receiver bias variabilities: An examination in the Polar Cap region and comparison to Incoherent Scatter Radar
        The problem of receiver Differential Code Biases (DCBs) in the use of GPS measurements of ionospheric Total Electron Content (TEC) has been a constant concern amongst network operators and data users since the advent of the use of GPS measurements for ionospheric monitoring. While modern methods have become highly refined, they still demonstrate unphysical bias behavior, namely notable solar cycle variability. Recent studies have highlighted the potential impact of temperature on these biases, resulting in small diurnal or seasonal behavior, but have not addressed the, far more dominant, solar cycle variability of estimated receiver biases. This study investigates the nature of solar cycle bias variability. We first identify the importance of the strongest candidate for these variabilities, namely shell height variability. It is shown that the Minimizations of Standard Deviations (MSD) bias estimation technique is linearly dependent on the user’s choice of shell height, where the sensitivity of this dependence varies significantly from 1 TECU per 4000km of shell height error in solar minimum winter to in excess of 1 TECU per 90km of shell height error during solar maximum summer. To assess the importance of these sensitivities, we present true shell height derived at Resolute, Canada using the Resolute Incoherent Scatter Radar (R-ISR), operated by SRI International and a Canadian Advanced Digital Ionosonde (CADI) operated by the Canadian High Arctic Ionospheric Network (CHAIN). This investigation demonstrates significant shell height variability translating to bias variabilities of up to several TECU. These variabilities, however, are found to be insufficient to account for all of the observed bias solar cycle variability. To investigate these variabilities further, we next compare Total Electron Content (TEC) measurements made by a CHAIN GPS receiver at Resolute to integrated electron density profiles derived from the nearby Resolute ISR. Taking the ISR measurements as truth, we find that ISR-derived GPS receiver biases vary in the same manner as those derived using the MSD or other bias estimation approaches. Based on these results, we propose that standard receiver DCB estimation techniques may be interpreting a significant portion of plasmaspheric electron content as DCBs, resulting in apparent diurnal, seasonal, and solar cycle DCB variability.
        Speaker: Mr David Themens (University of New Brunswick)
      • 216
        Transmission of Waves from a High-Frequency Ionospheric Heater to the Topside Ionosphere
        In the first year of operation of the ePOP instruments on the Canadian small satellite CASSIOPE, a number of passes were recorded during which the Radio Receiver Instrument (RRI) measured radiation from powerful high-frequency ground transmitters that act as ionospheric heaters. In the case of measurements of transionospheric propagation from the Sura heating facility in Russia, located at 56.15°N, 46.10°E, RRI reception of heater waves was accompanied by the operation of the trifrequency Coherent Electromagnetic Radio Tomography (CERTO) beacon on the satellite radiating at 150, 400 and 1067 MHz. CERTO waves, detected at three ground receivers near Sura, allowed total electron content to be measured continuously along the three different paths between CASSIOPE and the three ground sites. Subsequent tomographic processing provided the ionospheric electron density distribution as a function of latitude and altitude. With this density model tool in hand, ray-tracing was applied to the prediction at the spacecraft of various properties of the HF waves from the Sura heater. When compared with the observations, the predictions validate the relevance of geometric-optics principles in transionospheric propagation.
        Speaker: Dr Gordon James (University of Calgary)
      • 217
        Dawn-dusk asymmetry in the intensity of polar cap flows as seen by SuperDARN
        Polar cap flow pattern and intensity depend on the IMF Bz and By components. For IMF Bz<0, the pattern is consistently two-celled, and previous studies indicate that flows are fastest near noon and midnight for By<0 and during afternoon-dusk hours for By>0. In this study, we investigate the polar cap flow intensity in two ways. First we consider highly-averaged (over each month of observations in 2007-2013) convection patterns inferred from all SuperDARN radar measurements and discuss typical configurations of the polar cap region with enhanced flows, depending on the IMF By, with a focus on the dusk-dawn asymmetry. We demonstrate seasonal and perhaps solar cycle changes in the asymmetry. We then consider 2 years of Clyde River radar data on the azimuthal component of the flow and show the asymmetry observed directly. We discuss the complexity of the phenomenon in contrast to the more firm conclusions of previous studies.
        Speaker: Alexandre Koustov (U)
        Slides
    • T2-4 Fields and Strings (DTP) / Champs et cordes (DPT) CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Rainer Dick (University of Saskatchewan)
      • 218
        Scale and Conformal Invariance in Quantum Field Theory
        The behavior of coupling constants in quantum field theory under a change of energy scale is encoded in the renormalization group. At fixed points of the renormalization group flow, quantum field theories exhibit conformal invariance and are described as conformal field theories. The larger spacetime symmetry of conformal field theory is not the smallest possible extension of Poincare invariance. Indeed, scale invariance could occur without conformal invariance which would lead to scale field theories. We thus investigate the theoretical implications of scale invariance without conformal invariance in quantum field theory. We argue that renormalization group flows of such theories correspond to recurrent behaviors, i.e. limit cycles or ergodicity. We discuss the implications for the a-theorem, and use Weyl consistency conditions to show that scale invariance implies conformal invariance at weak coupling in four-dimensional quantum field theory. Finally, we clarify the necessary and sufficient conditions for conformality and present new types of conformal field theories.
        Speaker: Prof. Jean-Francois Fortin (Laval University)
        Slides
      • 219
        Dynamics of Gravitational Collapse in AdS Space-Time
        Gravitational collapse in asymptotically anti-de Sitter spacetime is dual to thermalization of energy injected to the ground state of a strongly coupled gauge theory. Following work by Bizon and Rostworowski, numerical studies of massless scalar fields in Einstein gravity indicate that generic initial states thermalize, given time, even for arbitrarily small energies. From the gravitational perspective, this appears due to a combination of a turbulent instability in the nonlinear local dynamics and the ability of matter to reflect from the conformal boundary. I will discuss recent work examining the effects of new length scales in the dynamics, including a scalar mass and higher-curvature corrections to the gravitational action.
        Speaker: Andrew Frey (University of Winnipeg)
      • 220
        Thermodynamic and Transport Properties of a Holographic Quantum Hall System
        We apply the AdS/CFT correspondence to study a quantum Hall system at strong coupling. Fermions at finite density in an external magnetic field are put in via gauge fields living on a stack of D5 branes in Anti-deSitter space. Under the appropriate conditions, the D5 branes blow up to form a D7 brane which is capable of forming a charge-gapped state. We add finite temperature by including a black hole which allows us to compute the low temperature entropy of the quantum Hall system. Upon including an external electric field (again as a gauge field on the probe brane), the conductivity tensor is extracted from Ohm’s law.
        Speaker: Joel Hutchinson (University of Alberta)
        Slides
      • 221
        Constraints and Bulk Physics in the AdS/MERA Correspondence
        It has been proposed that the Multi-scale Entanglement Renormalization Ansatz (MERA), which is efficient at reproducing CFT ground states, also captures certain aspects of the AdS/CFT correspondence. In particular, MERA reproduces the Ryu-Takayanagi-type formula and the network structure is similar to a discretized AdS space where the renormalization direction gives rise to the additional bulk dimension. Such discovery may enable us to study the important features of gravity/gauge duality in a more controlled setting. We will show that in order for MERA to recover bulk physics consistent with our current knowledge of holography, it has to satisfy certain consistency relations and that it can only capture bulk physics much larger than the AdS radius. A more specific framework to construct bulk-boundary dictionary, bulk states and Hilbert space from a boundary theory using MERA will also be discussed.
        Speaker: ChunJun Cao (Caltech)
        Slides
    • T2-5 Nuclear Structure II (DNP) / Structure nucléaire II (DPN) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Reiner Kruecken (TRIUMF)
      • 222
        Single particle structure in neutron-rich Sr isotopes approaching $N=60$
        The shape coexistence and shape transition at $N=60$ in the Sr, Zr region is the subject of substantial current experimental and theoretical effort. An important aspect in this context is the evolution of single particle structure for $N<60$ leading up to the shape transition region, which can be calculated with modern large scale shell model calculations using a $^{78}$Ni core or Beyond Mean Field Models. One-neutron transfer reactions are a proven tool to study single-particle energies as well as occupation numbers. Here we report on the study of the single-particle structure in $^{95-97}$Sr via ($d,p$) one-neutron transfer reactions in inverse kinematics. The experiments presented were performed at TRIUMF's ISAC facility using the TIGRESS gamma-ray spectrometer in conjunction with the SHARC charge particle detector. Highly charged beams of $^{94,95,96}$Sr, produced in the ISAC UCx target and charge-bred by an ECR source were accelerated to 5.5 MeV/$A$ in the superconducting ISAC-II linac before delivery to the experimental station. Other than their clear scientific value, these measurements were landmark being the first high mass ($A>30$) post-accelerated radioactive beam experiments performed at TRIUMF. Recent advances within the facility making the measurements posisble will be highlighted as well as initial results from the experiments discussed in the context of evolving single-particle structure.
        Speaker: Dr Peter Bender (TRIUMF)
      • 223
        Doppler shift lifetime measurements using the TIGRESS Integrated Plunger
        Along the $N=Z$ line, shell gaps open simultaneously for prolate and oblate deformations; the stability of these prolate and oblate configurations is enhanced by the coherent behaviour of protons and neutrons in $N=Z$ nuclei. Additionally, amplification of proton-neutron interactions along the $N=Z$ line may yield information on the isoscalar pairing interactions which have been predicted in many nuclear models but not yet experimentally observed. Electromagnetic transition rates measured via Doppler shift lifetime techniques are recognized as a sensitive probe of collective behavior and shape deformation and can be used to discriminate between model calculations. To take advantage of this opportunity, the TIGRESS Integrated Plunger (TIP) has been constructed at Simon Fraser University. The current TIP infrastructure [1] supports lifetime measurements via the Doppler Shift Attenuation Method (DSAM). One advantage of Doppler shift lifetime measurements is that lifetimes can be extracted independent of the reaction mechanism. TIP has been coupled to the TIGRESS segmented HPGe array at TRIUMF as part of the experimental program at ISAC-II. The initial studies using TIP employ fusion-evaporation reactions. Here, reaction channel selectivity can greatly enhance the sensitivity of the measurement. To enable channel selection, the 24-element TIP CsI wall was used for evaporated light charged-particle identification. Reaction channel selectivity has been demonstrated using the TIP infrastructure following the successful production of the $N=Z$ nucleus $^{68}$Se via the $^{36}$Ar + $^{40}$Ca fusion-evaporation reaction. A Geant4-based code for TIP is being developed as a tool to aid the analysis and for the optimization of future experiments. The device, experimental approach, analysis, and preliminary results will be presented and discussed. [1] P. Voss et al., Nucl. Inst. and Meth. A746, (2014) 87.
        Speaker: Mr Aaron Chester (Simon Fraser University Department of Chemistry)
      • 224
        Isomeric decay spectroscopy of 96Cd
        Self-conjugate nuclei, where $N=Z$, exhibit a strong $pn$ interaction due to the large overlap of wavefunctions in identical orbitals. The heaviest $N=Z$ nuclei studied so far is $^{92}$Pd, and it has demonstrated a strong binding in the $T = 0$ interaction [1]. As the mass number increases, the nucleus approaches the doubly-magic $^{100}$Sn. To investigate the evolution of the $pn$ interaction strength near the shell closure $N = Z = 50$, experimental results on the next self-conjugate, even-even nucleus $^{96}$Cd are needed. Record quantities of $^{96}$Cd were produced at RIKEN Radioactive Isotope Beam Factory, via fragmentation of an intense $^{124}$Xe beam on a thin $^{9}$Be target. Their decay products were measured with EURICA, consisting of HPGe/LaBr$_3$ detectors for gamma-rays, and WAS3ABI, a set of position-sensitive silicon detectors for positrons, protons and ions. A high-spin isomeric state in $^{96}$Cd was found, along with gamma-ray transitions that populate both the ground state and the 16$^{+}$ spin-trap isomeric state. Isomer half-lives and the proposed experimental level scheme of $^{96}$Cd will be presented, followed by a discussion of its $pn$ interaction strength and the decay to $^{96}$Ag.
        Speaker: Jason Park (University of British Columbia/TRIUMF)
        Slides
      • 225
        The Electromagnetic Mass Analyser EMMA
        The Electromagnetic Mass Analyser EMMA is a recoil mass spectrometer for TRIUMF's ISAC-II facility designed to separate the recoils of nuclear reactions from the heavy ion beams that produce them and to disperse the recoils according to their mass/charge ratio. In this talk I will present an update on the construction and commissioning of the spectrometer and its components.
        Speaker: Barry Davids (TRIUMF)
      • 226
        New decay modes of the high-spin isomer of $^{124}$Cs
        As part of a broader program to study the evolution of collectivity in the even-even nuclei above tin, a series of $\beta$-decay measurements of the odd-odd Cs isotopes into the even-even Xe isotopes, specifically $^{122,124,126}$Xe, have been made utilizing the 8$\pi$ spectrometer at TRIUMF-ISAC. The 8$\pi$ spectrometer consisted of 20 Compton-suppressed high-purity germanium (HPGe) detectors and the Pentagonal Array of Conversion Electron Spectrometers (PACES), an array of 5 Si(Li) conversion electron detectors. The decay of $^{124}$Cs to $^{124}$Xe is the first measurement to be fully analyzed. A very high-statistics data set was collected and the $\gamma\gamma$ coincidence data were analyzed, greatly extending the $^{124}$Xe level scheme. Several weak $\it{E2}$ transitions into excited 0$^+$ states in $^{124}$Xe were observed. The $\it{B(E2)}$ transition strengths of such low-spin transitions are very important in determining collective properties, which are currently poorly characterized in the region of the neutron-deficient xenon isotopes. A new $\beta^+$/EC-decay branch from a high-spin isomeric state of $^{124}$Cs has been observed for the first time. Decay of the isomer ($J^\pi$ = (7)$^+$, $T_{1/2}$ = 6.3(2) s) is seen to populate high-spin states in the $^{124}$Xe daughter nucleus that are otherwise inaccessible through the $\beta$-decay of the 1$^+$ $^{124}$Cs ground state. Combining $\gamma\gamma$ as well as $\gamma$-electron coincidence data, several new transitions in the isomeric decay of the (7)$^+$ state have been observed. The characterization of the new $\beta$-decay branch and the isomeric decay of the high-spin state will be presented.
        Speaker: Allison Radich (University of Guelph)
        Slides
    • T2-6 Nuclear Physics in Medicine (DNP-DMBP-DIAP) / Physique nucléaire en médecine (DPN-DPMB-DPIA) CAB 239

      CAB 239

      University of Alberta

      Convener: Zisis Papandreou (University of Regina)
      • 227
        Accelerator-Based Medical Isotope Production at TRIUMF
        TRIUMF operates a suite of [H-] cyclotrons (13, 2 x 30, 42 and 500 MeV) which, in addition to supplying our basic science program, are used to produce a variety of medical isotopes. Within the next few years TRIUMF will also begin isotope production in our new Advanced Rare IsotopE Laboratory (ARIEL) – a 50 MeV, 10 mA continuous-wave electron linac. The breadth and power of our infrastructure has positioned TRIUMF to be a major producer for some medical isotopes, while enabling access to others that are less common. Since 2010, a TRIUMF-led collaboration has sought to produce Tc-99m directly on small cyclotrons via the Mo-100(p,2n) reaction. Recent successes have shown >30 Ci (1110 GBq) of Tc-99m produced in a single 6 hr irradiation on a 450 µA TR30 cyclotron (at 24 MeV) at TRIUMF. Solutions for 16 and 19 MeV cyclotrons have also been developed. Our goal is to enable all Canadian cyclotron centres to produce Tc-99m in lieu of the imminent cessation of isotope production at the Chalk River reactor. TRIUMF is also pursuing novel methods for producing radiometals that are of interest to the medical community. We have demonstrated the utility of liquid targets for producing research quantities of Zr-89, Ga-68, Y-86 and Sc-44; made by irradiating salt solutions of the appropriate starting material. To date, mCi (MBq) quantities have been isolated and purified, opening the door for the development of novel radiopharmaceuticals. Finally, a brief discussion will ensue on efforts to apply Isotope Separation On-Line (ISOL) infrastructure within the ISAC facility at TRIUMF to produce research quantities of radiotherapeutic isotopes. Progress on the isolation of alpha emitters At-211 and Ac-225 will be presented. TRIUMF seeks to enable clinical trials with these and many other potentially useful radiotherapeutic isotopes available through our existing science program. Overall, TRIUMF’s Nuclear Medicine program seeks to address current and anticipated challenges in the production of important clinical isotopes. With over 1000 small (<30 MeV) cyclotrons in 70 countries, the time is ripe to establish accelerators as a viable, decentralized source of medical radionuclides.
        Speaker: Paul Schaffer (TRIUMF)
        Slides
      • 228
        Producing Medical Isotopes with Electron Linacs
        The Canadian Light Source (CLS) has been working on a project to develop a facility that uses a 35 MeV high power (40 kW) electron linac to produce medical isotopes. This project was funded by Natural Resources Canada’s Non-reactor-based Isotope Supply Program which was initiated following the lengthy shutdowns of the NRU reactor at Chalk River that caused significant shortages of molybdenum-99/technetium-99m isotopes for the medical community. The CLS has been collaborating with the Prairie Isotope Production Enterprise (PIPE) in Winnipeg to develop an entire production cycle from molybdenum targets through to clinical approval by Health Canada of linac-derived isotopes. This talk will outline the reasons for using electron linacs for this application, as well as many of the broader challenges encountered to develop an alternate supply chain for these vital isotopes.
        Speaker: Mark de Jong (Canadian Light Source Inc.)
        Slides
      • 229
        Calculation of isotope yields for radioactive beam production
        Access to new and rare radioactive isotopes is key to their application in nuclear science. Radioactive ion beam (RIB) facilities around the world, such as TRIUMF (Canada's National Laboratory for Particle and Nuclear Physics, 4004 Westbrook Mall, Vancouver, BC, V6T 2A3), work to develop target materials that generate ion beams used in nuclear medicine, astrophysics and fundamental physics studies. At Simon Fraser University, we are developing a computer simulation of the RIB targets at TRIUMF to augment the existing knowledge and to support future target developments. This simulation will be used to predict the amounts of isotopes produced by the targets in use at TRIUMF to allow for better experiment preparation as well as to gauge the efficiency of using new target materials and varying driver beam intensities to generate different ranges of isotopes. The simulation, built in GEANT4 (Geant4 - A Simulation Toolkit, S. Agostinelli et al., Nuclear Instruments and Methods A 506 (2003) 250-303), a Monte Carlo nuclear transport toolkit, consists of a target of 300 uranium carbide disks, each 120 microns thick, encased in a tantalum container, which is then bombarded by a 480 MeV proton beam, as per the specifications of the TRIUMF target station. The simulation records the isotopes generated as well as their formation process (i.e. fission, fragmentation and neutron capture) and other related properties such as residual kinetic energy of the reaction products. These results are then compared to data gathered at the TRIUMF yield station (P. Kunz, C. Anreoiu, et al. Rev. Sci. Instrum. 85 (2014) 053305), a nuclear spectroscopy experiment dedicated to RIB characterization. Results from the simulation will be presented, along with benchmarking and comparison to the yield station data and other nuclear transport codes.
        Speaker: Ms Fatima Garcia (Simon Fraser University and TRIUMF)
        Slides
      • 230
        Coincidence Measurements using the SensL MatrixSM-9 Silicon-photomultiplier Array
        The silicon photomultiplier (SiPM) has emerged as a rival device to traditional photodetectors such as the photomultiplier tube (PMT). Over the past decade, SiPMs - also known as Multi-pixel photon counters (MPPCs) and Single-photon avalanche diodes (SPADs) - have found applications in fields ranging from, for example, high-energy physics and atmospheric lidar, to homeland security, biophotonics and nuclear medicine. Due to their wide-ranging applications, arrays of SiPMs are now available commercially as part of modular, turnkey readout systems. One such device - the MatrixSM-9 manufactured by SensL - has been designed specifically for use in high-resolution medical imaging systems required in, for example, state-of-the-art PET applications. We present preliminary coincidence measurements using the Matrix SM-9 system, coupled to a plastic scintillator, to image a $^{22}$Na positron source.
        Speaker: Dr Jamie Sanchez-Fortun Stoker (University of Regina)
        Slides
    • T2-7 Energy Frontier: Susy & Exotics II (PPD) / Frontière d'énergie: supersymétrie et particules exotiques II (PPD) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Prof. Dean Karlen (University of Victoria (CA))
      • 231
        Searches for Exotic Physics at ATLAS
        The most exciting discovery to come from the LHC would be that of something completely unexpected. To that end, the ATLAS experiment has been enthusiastically analyzing the 2012 LHC data recorded at a centre of mass energy of 8 TeV looking for any possible evidence of new physics. A variety of signatures has been considered, including heavy resonances, excesses above the Standard Model expectation in numerous channels, and particles that are long-lived, highly ionizing, or invisible. This talk will explore some of these searches and touch on the various interpretations, such as dark matter, extra dimensions, and other intriguing extensions to the Standard Model.
        Speaker: Wendy Taylor (York University (CA))
        Slides
      • 232
        A Search for Magnetic Monopoles and Exotic Long-lived Particles with Large Electric Charge at ATLAS
        A search for highly ionizing particles produced in 8 TeV proton-proton collisions at the LHC is performed with the ATLAS detector. A dedicated trigger increases significantly the sensitivity to signal candidates stopping in the electromagnetic calorimeter and allows to probe particles with higher charges and lower energies. Production cross section limits are obtained for stable particles in the mass range $200-2500$ GeV for magnetic charges in the range of Dirac charge $0.5<|g|<2.0$ and for electric charges in the range $10<|z|<60$. Limits are presented for various pair-production scenarios, and model-independent limits are presented in fiducial regions of particle energy and pseudorapidity.
        Speaker: Mr Gabriel David Palacino Caviedes (York University (CA))
        Slides
      • 233
        The MoEDAL Experiment at the LHC - a New Light on the High Energy Frontier
        In 2010 the Canadian led MoEDAL experiment at the Large Hadron Collider (LHC) was unanimously approved by CERN's Research Board to start data taking in 2015. MoEDAL is a pioneering experiment designed to search for highly ionizing avatars of new physics such as magnetic monopoles or massive (pseudo-)stable charged particles. Its groundbreaking physics program defines over 30 scenarios that yield potentially revolutionary insights into such foundational questions as: are there extra dimensions or new symmetries; what is the mechanism for the generation of mass; does magnetic charge exist; what is the nature of dark matter; and, how did the big-bang develop. MoEDAL's purpose is to meet such far-reaching challenges at the frontier of the field. The innovative MoEDAL detector employs unconventional methodologies tuned to the prospect of discovery physics. The largely passive MoEDAL detector, deployed at Point 8 on the LHC ring, has a dual nature. First, it acts like a giant camera, comprised of nuclear track detectors - analyzed offline by ultra fast scanning microscopes - sensitive only to new physics. Second, it is uniquely able to trap the particle messengers of physics beyond the Standard Model for further study. MoEDAL's radiation environment is monitored by a state-of-the-art real-time TimePix pixel detector array. I shall also briefly discuss a new proposal to include a new active MoEDAL sub-detector to search for millicharged particles.
        Speaker: James Pinfold (University of Alberta (CA))
        Slides
    • T2-8 Cosmic frontier: Dark matter II (PPD) / Frontière cosmique: matière sombre II (PPD) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: Aksel Hallin (University of Alberta)
      • 234
        Status of the PICASSO and PICO experiments
        The PICO collaboration, a merger of COUPP and PICASSO experiments, searches for dark matter particles using superheated fluid detectors. These detectors can be operated within a set of conditions where they become insensitive to the typically dominant electron recoil background. Additionally, the acoustic measurement of the bubble nucleation makes possible the rejection of additional backgrounds such as alpha decays. This technique also allows for the target nuclei to be changed within the same experiment in order to confirm the properties of dark matter. This presentation reports on the PICASSO experiment that completed taking data in 2014, and the PICO-2L and PICO-60 experiments that were recently commissioned at the Snolab deep underground laboratory in Sudbury.
        Speaker: Dr Guillaume Giroux (Queen's University)
        Slides
      • 235
        DEAP-3600 trigger - the needle in the haystack
        DEAP-3600 is a dark matter experiment based at SNOLAB. It uses 3600kg of liquid argon as a target, and searches for scintillation light from argon nuclei struck by weakly interacting massive particles (WIMPs). Argon-39 atoms also undergo beta decay, and the recoiling electrons also produce scintillation light. Beta decays are expected to occur at least $10^8$ times as frequently as WIMP interactions, and the DEAP-3600 trigger is critical in filtering out the vast majority of background events, while keeping 100% of signal events. This talk will explain the very flexible trigger scheme that was developed, and will detail the commissioning and optimisation of the system.
        Speaker: Ben Smith (TRIUMF)
        Slides
      • 236
        Early studies of detector optical calibrations for DEAP-3600
        The DEAP-3600 experiment is looking for dark matter WIMPs by detecting the scintillation light produced by a recoiling liquid argon nucleus. Using a 1 tonne fiducial volume a WIMP-nucleon cross section sensitivity of 10^{-46} cm2 in is expected for 3 years of data taking for a 100GeV WIMP. DEAP-3600 has been designed for a target background of 0.6 events in the WIMP region of interest in 3 years of data taking. In this talk I will present the status of the commissioning of the optical data collected by DEAP.
        Speaker: Dr Berta Beltran (Univeristy of Alberta)
        Slides
      • 237
        Single photon counting for the DEAP dark matter detector
        DEAP-3600, comprised of a 1 tonne fiducial mass of ultra-pure liquid argon, is designed to achieve world-leading sensitivity for spin-independent dark matter interactions. DEAP-3600 measures the time distribution of scintillation light from the de-excitation of argon dimers to select events. This measurement allows background events from Ar39 decays to be rejected at a high level. The performance of this analysis critically relies on DEAP’s ability to identify pulses in the waveforms of the photomultilier tubes and accurately assessing the number of photo-electrons contributing to each pulse. Photomultiplier tube effects, such as dark noise and afterpulsing, can degrade the measurement and weaken the level of background discrimination. An algorithm has been developed for finding pulses and identifying the number of photo-electrons.
        Speaker: Thomas McElroy (University of Alberta)
        Slides
    • T2-9 Gender and Arts in Physics Teaching (CEWIP-DPE) / Genre et arts dans l'enseignement de la physique (CEFEP-DEP) CCIS L1-160

      CCIS L1-160

      University of Alberta

      Convener: Dr Marina Milner-Bolotin (The University of British Columbia)
      • 238
        Model-Based Reasoning in Upper-division Lab Courses
        Modeling, which includes developing, testing, and refining models, is a central activity in physics. Well-known examples from include everything from the Bohr model of the hydrogen atom to the Standard Model of particle physics. Modeling, while typically considered a theoretical activity, is most fully represented in the laboratory where measurements of real phenomena intersect with theoretical models, leading to refinement of models and experimental apparatus. However, experimental physicists use models in complex ways and the process is often not made explicit in physics laboratory courses. We have developed a framework to describe the modeling process in physics laboratory activities. The framework attempts to abstract and simplify the complex modeling process undertaken by expert experimentalists. The framework can be applied to understand typical processes such the modeling of the measurement tools, modeling “black boxes,” and signal processing. We demonstrate that the framework captures several important features of model-based reasoning in a way that can reveal common student difficulties in the lab and guide the development of curricula that emphasize modeling in the laboratory. We also use the framework to examine troubleshooting in the lab and guide students to effective methods and strategies.
        Speaker: Heather Lewandowski (University of Colorado)
      • 239
        Fabulous Physicists from Around the World: The tale of ICWIP 2014
        A century ago it was only Marie Curie and a few other women who were part of the physics community, but in 2014, CAP and IUPAP (International Union of Pure and Applied Physics) brought over 200 women physicists from 52 countries to Waterloo for the 5th IUPAP International Conference on Women in Physics (ICWIP). ICWIP 2014 was held at Wilfrid Laurier University from August 5 to 8, 2014. This was the first time this conference was held in North America. It was a unique opportunity for Canadian scientists and researchers to share ideas and experiences with women and men from around the world. This is the story of this one-of-a-kind conference, including the scientific and gender-focused sessions and talks, the official resolutions approved by the delegates, the amazing personal stories shared, and of course, the closing night dance party.
        Speaker: Shohini Ghose (Wilfrid Laurier University)
      • 240
        Gender gaps in a first-year physics lab
        It has been established that male students outperform female students on almost all commonly-used physics concept inventories. However, there is significant variation in the factors that contribute to this gender gap, as well as the direction in which they influence it. It is presently unknown if such a gender gap exists on the relatively new Concise Data Processing Assessment (CDPA). To get at estimates of the gap, we have measured performance on the CDPA at the pre-test and post-test level in the first-year physics lab at the University of British Columbia. We find a gender gap on the CDPA that persists from pre- to post-test and that is as big as, if not bigger than, similar reported gaps. That being said, we ultimately claim no evidence that female students are less capable of learning than their male peers, and we suggest caution when using gain measures alone to draw conclusions about differences in science classroom performance across gender.
        Speaker: Dr James Day (University of British Columbia)
        Slides
    • Health Break (with exhibitors) / Pause santé (avec exposants) CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • T3-1 Materials characterization: electrical, optical, thermal (DCMMP) / Caractérisation des matériaux: électrique, optique, thermique (DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Wayne Hiebert (National Institute for Nanotechnology)
      • 241
        A pump-probe technique to measure the Curie temperature distribution of exchange-decoupled nanoscale ferromagnet ensembles
        Heat assisted magnetic recording (HAMR) has been recognized as a leading technology to increase the data storage density of hard disk drives[1]. Dispersions in the properties of the grains comprising the magnetic medium can lead to grain-to-grain Curie temperature variations, which drastically affect noise in the recorded magnetic transitions, limiting the data storage density capabilities in HAMR[2]. In spite of the need to investigate the origin of the Curie temperature distribution ($\sigma_{Tc}$) and establish means to control it, no approach to measure $\sigma_{Tc}$ has been available. We have recently presented a method to measure the switching temperature distribution of an ensemble of exchange-decoupled grains with perpendicular anisotropy subject to nanosecond heating pulses of varying intensity[3]. The rapid cooling rate ensures that the grain magnetization is not affected by thermal activation, so that the grains switch at Tc. A switching temperature distribution can then be directly interpreted as a measure for $\sigma_{Tc}$. Here we summarize the results of this measurement routine to a series of FePt HAMR media samples in which the degree of *L*$1_{0}$ chemical ordering and alloy composition is systematically varied. We also present modeling results based on the Landau-Lifshitz-Bloch formalism that validates the experimental approach and provides experimental bounds for its validity[4]. Measurements of $\sigma_{Tc}$ reveal a sizable dependence, which we interpret in the context of thermodynamic drive for disordered to ordered crystalline structure phase transformation. Besides the ability to measure $\sigma_{Tc}$, which is of importance to engineer suitable HAMR media capable of high density magnetic recording, the presented technique can be applied to studies on the competition between Zeeman energy and thermal fluctuations that affect the switching probability upon cooling from Tc. [1] D. Weller, O. Mosendz, G.J. Parker, S. Pisana, and T.S. Santos, Phys. Status Solidi A 210, 1245 (2013). [2] H. Li and J.-G. Zhu, IEEE Tran. Magn. 49, 3568 (2013). [3] S. Pisana, S. Jain, J.W. Reiner, C.C. Poon, O. Hellwig, B.C. Stipe, Appl. Phys. Lett. 104, 162407 (2014). [4] S. Pisana, S. Jain, J.W. Reiner, O. Mosendz, G.J. Parker, M. Staffaroni, O. Hellwig, B.C. Stipe, IEEE Tran. Magn., in press.
        Speaker: Prof. Simone Pisana (York University)
      • 242
        Optical properties and Fermiology near field-tuned quantum critical points
        In the so-called "heavy-fermion" metals, the hybridization of the conduction band with electrons localized in partially filled $f$ orbitals leads to the formation of heavy quasiparticles, for which the effective mass can be renormalized by a factor of 100 or more. However, the itinerant nature of these quasiparticles competes with a tendency to form more conventional, magnetically ordered states. These materials are therefore situated near a quantum critical point - a zero-temperature phase transition driven by the competition between kinetic energy and potential energy. This conflict between itinerancy and localization lies at the heart of all correlated electron materials, and makes heavy-fermion systems a model system for testing and understanding correlated quantum matter. Along with the formation of ultra-heavy quasiparticles, the scattering dynamics in heavy fermion compounds also undergo a strong renormalization. This critical slowing-down brings important electronic timescales, such as electronic scattering rates, down into the GHz range, where optical-type measurements and analyses can be carried out with microwaves. We have developed a dilution-refrigerator-based system for carrying out these measurements, and have used it to study a range of heavy fermion materials such as CeCoIn5, UBe13 and URu2Si2. Following an overview of the relevant physics, I will present a summary of our most striking results, illustrating the critical slowing down and mass enhancement that accompany a quantum phase transition.
        Speaker: David Broun (Simon Fraser University)
      • 243
        Protein Biosensing with Fluorescent-Core Microcapillaries
        Whispering gallery modes (WGMs) are the electromagnetic resonances of dielectric spheres, cylinders, or rings. The WGM wavelengths can shift when the resonant field interacts with a local analyte fluid. This work demonstrates a fluorescent core microcapillary that utilizes WGMs for biosensing applications. This device consists of a glass microcapillary with a 50-μm-diameter inner channel. The channel wall is coated with a film composed of fluorescent silicon quantum dots (SiQDs). Because the SiQD film has a higher index of refraction than the glass capillary wall, it can support cylindrical WGMs. The QD fluorescence spectrum thus consists of a set of sharp peaks at the WGM resonance wavelengths. Part of the WGM field extends into the capillary channel where it samples the fluids pumped inside; thus the cavity resonance wavelengths in the QD fluorescence spectrum depend on the channel medium. The sensitivity of the WGM wavelengths varied between 3 and 24 nm per refractive index unit, depending on the SiQD film thickness. Biosensing with this device was then demonstrated using the standard biotin-avidin system. The QD film in the capillary channel was coated with alternating charged polyelectrolyte (PE) layers with exposed amines for attaching biotin. Biotin in turn has a high specific affinity for the neutravidin protein. These biotinylated PE layers were found to capture neutravidin, yielding a detection limit of 6 nM and an equilibrium association constant of 1.1 x 106 M-1 for biotin-neutravidin in this sensor. Several “blank” runs indicate minimal nonspecific binding. Attractive features of this device include a high degree of physical robustness and minimal equipment requirements (e.g., a tuneable laser is not needed to scan the cavity modes). Future work will aim to increase the so-far moderate detection limit, potentially by improving the device sensitivity via finer control over the SiQD film thickness.
        Speaker: Mr Stephen Lane (University of Alberta)
      • 244
        Ultrafast modulation of photoluminescence in semiconductors by intense terahertz pulses
        Terahertz (THz) pulse science is a rapidly developing field, and has been applied extensively in the characterization of ultrafast dynamics in semiconductors and nanostructures. The recent development of intense THz pulse sources in lithium niobate (LN), however, allows the dynamics of transient states to be directly manipulated by the large electric field of the THz pulse itself. We have used an ultrafast laser source to generate intense THz pulses in LN with picosecond duration and peak electric fields up to 300 kV/cm. Here we study how these intense THz pulses affect the ultrafast radiative recombination dynamics of photoexcited carriers in semiconductors and semiconductor nanostructures. In GaAs, we observe a sharp transition between THz-pulse-induced quenching and enhancement of photoluminescence (PL) with increasing photoexcited carrier densities. We present spectrally-resolved PL measurements of this transition, which reveal a competition between enhancement at shorter wavelengths versus quenching at longer wavelengths. The dynamics of this interplay between THz pulse enhanced and quenched PL are presented as a function of excitation fluence and time-delay between the excitation and THz pulses. Possible mechanisms that include THz-induced carrier heating and scattering processes are discussed. The effects of intense THz pulses on the PL dynamics in polycrystalline GaAs, and quantum well structures will also be explored. The ability to control material properties with intense THz pulses may lead to novel optoelectronic devices with the ability to modulate light emission on picosecond timescales. This work was supported by NSERC, CFI, ASRIP, AITF, iCiNano, and nanoBridge.
        Speaker: Mr David Purschke (University of Alberta)
    • T3-10 Special session to honour Dr. Akira Hirose II (DPP) / Session spéciale en l'honneur du Dr Akira Hirose II (DPP) CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Chijin Xiao (Univ. of Saskatchewan)
      • 245
        From Plasma to Complex Plasma
        Earlier research on plasma turbulence and later research development on a complex plasma are discussed. Study of nonlinear evolution of instabilities in a collisionless plasma, especially ion acoustic instability and Buneman instability, revealed the role of plasma collective modes in the heating of plasma particles. It was essential for plasma waves to grow in time, resulting in the heating of plasma itself through effective interaction of plasma particles and plasma waves. Theoretical study revealed the time constant for the heating to occur in a plasma. When plasma instabilities are well developed and spread wide in frequency range, the plasma turbulence caused the broadening of wave-particle resonance region. The earlier plasma experiments tried to eliminate any impurities from the vacuum chamber to guarantee the experimental conditions as much as ideal theoretical bases. However, the onset conditions of plasma instabilities are found to be modified in the presence of dust particles, micron in size and negatively charged. The presence of dust particles is found to modify the effective temperature of electrons, resulting in the suppression of the Landau damping. Furthermore, the dust plasma, now known as a complex plasma because of the nature of complex system as a composite of plasma particles and dust particles, is found to be rich in fundamental novel physics including a strongly coupled state and the anomalous nature of electromagnetic propagation in the medium. Dust particles when placed in a sheath interact each other in the presence of ion flow and produce a line along the flow. The paired chain was interpreted as a pair-formation by the exchange of phonons. The dust particles could be floated at the sheath edge producing a one- or a two-dimensional lattice structure, which provides a platform for the study of low-dimensional behavior of Coulomb systems. Some of the current topics of a complex plasma are discussed.
        Speaker: Prof. Osamu Ishihara (Chubu University/Yokohama National University)
      • 246
        Fluctuations and Transport in Hall devices with ExB drift
        Devices with stationary, externally applied, electric field which is perpendicular to a moderate amplitude magnetic field B₀, are now a common example of magnetically controlled plasmas. High interest applications involve Penning type plasma sources, magnetrons for plasma processing, magnetic filters for ion separation, and electric space propulsion devices such as Hall thrusters. One common characteristic of these numerous applications are plasma parameters conditions in which electrons are magnetized so the electron Larmor radius is much smaller than the characteristic lengths scale of the devices, while ions have large Larmor radius and do not feel the magnetic field and thus can be easily controlled by the electric field. The latter is a basis of various useful applications for ions extraction, separation and acceleration. Similar conditions also occur in some ionospheric plasmas as well as in some laboratory experiments on magnetic reconnection. The proposed talk reviews physics basis of such Hall plasma discharges. Application of the external electric field perpendicular to the magnetic field, as well as gradients of plasma density, temperature and magnetic field, naturally present in such discharges, result in plasma fluctuations and instabilities that make plasma turbulent and electron transport anomalous. Specific conditions of such plasmas precludes existence of standard drift waves, however other modes, the so called anti-drift modes become possible and unstable. The open magnetic field lines (terminated by the wall) also result in new instabilities, the so called sheath impedance modes. This talk provides physics based description of various modes and instabilities pertinent to such Hall plasmas and resulting anomalous electron transport due to these modes.
        Speaker: Dr Andrei Smolyakov (University of Saakatchewan)
      • 247
        Adaptive Matrix Transpose Algorithms for Distributed Multicore Processors
        The matrix transpose is an essential primitive of high-performance parallel computing. In plasma physics and fluid dynamics, a matrix transpose is used to localize the computation of the multidimensional Fast Fourier transform, the engine that powers the pseudospectral collocation method. An adaptive parallel matrix transpose algorithm optimized for distributed multicore architectures running in a hybrid OpenMP/MPI configuration is presented. Significant boosts in speed are observed relative to the distributed transpose used in the state-of-the-art adaptive FFTW library. In some cases, a hybrid configuration allows one to reduce communication costs by reducing the number of MPI nodes, and thereby increasing message sizes. This also allows for a more slab-like than pencil-like domain decomposition for multidimensional Fast Fourier Transforms, reducing the cost of, or even eliminating the need for, a second distributed transpose. Nonblocking all-to-all transfers enable user computation and communication to be overlapped. We apply adaptive matrix transposition algorithms on hybrid architectures to the parallelization of implicitly dealiased pseudospectral convolutions used to simulate turbulent flow. Implicit dealiasing outperforms conventional zero padding by decoupling the data and temporary work arrays. Parallelized versions of our implicit dealiasing algorithms for hybrid architectures are publically available in the open-source library FFTW++.
        Speaker: John Bowman (University of Alberta)
      • 248
        Dense Plasma Focus for Short-Lived Isotope Activation
        Short-lived radioisotopes (SLRs) are used for medical applications including positron emission tomography (PET). The required activity for N-13for PET is about 4 GBq for a myocardial blood perfusion assessment. Dense plasma focus (DPF) has been considered as a low cost methods for producing SLRs as an alternative to conventional cyclotron facilities. A low energy dense plasma focus has been built and optimized at the University of Saskatchewan to study the feasibility of SLRs production, in particular N-13 using energetic deuteron ion beams produced in a dense plasma focus. X-ray detectors and a Faraday cup have been used to characterize the DPF properties, particularly the ion beam energy based on time-of-flight measurements. The preliminary results have shown generation of ions with energies up to 2 MeV, well exceeding the threshold energy for N-13 production (328 keV). Electrical signals have been used for circuit analyses in order to interpret the anomalous plasma resistance and plasma inductance during the pinch phase. Simulation of N-13 activation using deuteron beam has been carried out.
        Speaker: Mr R. A. Behbahani (University of Saskatchewan)
    • T3-2 Quantum Computation and Communication (DTP-DCMMP-DAMOPC) / Communication et calcul quantique (DPT-DPMCM-DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Arundhati Dasgupta (University of Lethbridge)
      • 249
        Improving Physical Models of Qubit Decoherence and Readout
        Qubit coherence measurements are now sufficiently accurate that they can be used to perform 'spectroscopy' of noise due to a complex environment. Measuring not only the decay time, but also the form of decay as a function of some external parameter (e.g. temperature) can determine the nature of the dominant decoherence source. I will describe how temperature-dependent measurements of qubit decoherence time and form of decay can distinguish between a number of different possible sources of environmental charge flucutations (including tunneling and cotunneling with a continuum band, as well as one- and two-phonon absorption processes). These results can be used to identify and suppress dominant charge-noise dephasing mechanisms in semiconductor nanostructures. I will also briefly discuss some new tricks to enhance the fidelity of generic qubit readouts by understanding the physical dynamics of these systems.
        Speaker: Prof. Bill Coish (McGill University)
      • 250
        NanoQEY Quantum Key Distribution Satellite
        NanoQEY (Nano Quantum EncrYption satellite) is a demonstration satellite which will show the feasibility of implementing Quantum Key Distribution (QKD) between two ground stations on earth using a satellite trusted node approach. One of the main objectives of NanoQEY is to eliminate the necessity for a fine pointing system which will reduce cost and planning time for a satellite. The system will also be simplified from many models that have been proposed due to the smaller space and mass allowances. A few of the QKD satellites that have been proposed are also formatted in the downlink scenario, whereas NanoQEY will be implemented in an uplink scenario. Since the satellite is only used for photon collection and data processing, it is not necessary to have many of the complicated systems on board which would be required for a downlink. The main purpose of NanoQEY is to construct a payload which will be operational for a QKD demonstration and fit onto a nano-satellite in terms of mass and power budgets. However, because of the fine pointing simplification of the satellite, the ground stations will need to compensate for the lack of targeting on the satellite. These ground stations will have to have very fine pointing and tracking capabilities. We have undergone a study to determine the feasibility of a nano-satellite project to implement QKD for world-wide QKD demonstrations and the requirements on a ground station to achieve these goals.
        Speaker: Christopher Pugh (University of Waterloo)
      • 251
        Towards a Quantum Non-Demolition Measurement for Photonic Qubits
        Many applications of quantum information processing benefit from, or even require, the possibility to detect the number of photons in a given signal pulse without destroying the photons nor the encoded quantum state. We propose and show first steps towards the implementation of such a Quantum Non-Demolition (QND) measurement for time-bin qubits. To implement this measurement, we first store a ‘probe’ pulse in a cryogenically cooled Tm:LiNbO3 waveguide using an Atomic Frequency Comb (AFC) quantum memory protocol [1]. We then send a ‘signal’ pulse comprised of two temporal modes off-resonantly with the AFC through a previously prepared transparency window. The off-resonant interaction between the propagating signal and the thulium ions, onto which the probe pulse was mapped, results in the atomic state acquiring a phase-shift. This phase shift is imprinted onto the recalled probe pulse and can be determined using an interferometric measurement. The magnitude of this phase-shift depends on the signal pulse's energy, and detuning w.r.t to the probe pulse. Hence, knowing the phase-shift, we can determine the intensity or the number of photons in the signal pulse. [1] E. Saglamyurek et al, … Nature 2011
        Speaker: Chetan Deshmukh (University of Calgary)
      • 252
        Evanescent Waveguide Microscopies for Bio-Application
        Two new evanescent field microscopy technologies based on glass slab waveguides with permanent coupling gratings are introduced: waveguide evanescent field fluorescence (WEFF) microscopy and waveguide evanescent field scattering (WEFS) microscopy. The technologies are briefly described and the experimental setup based on a conventional inverted microscope is introduced and compared to existing technologies like TIR and TIRF. The advantages over the existing technologies are clearly addressed. For each technology one application in cell biology is shown. With multimode WEFF microscopy, taking at least two images with two different waveguide modes, it is possible to determine the fluorescence dye location above the waveguide surface. Therefore 2D dye distance maps or 3D contour plots can be calculated for the samples. As an example, the bending of the plasma membranes of cells between focal adhesions and focal contacts to the waveguide surface are investigated. WEFS microscopy which works as a label-free microscopy is used to analyse bacterial biofilm formation: from a parent cell to micro-colonies. In addition experiments on bacterial UV sterilization and its consequences on biofilm formation are shown.
        Speaker: Prof. Silvia Mittler (University of Western Ontario)
    • T3-3 Ground-based / in situ observations and studies of space environment III (DASP) / Observations et études de l'environnement spatial, sur terre et in situ III (DPAE) CAB 243

      CAB 243

      University of Alberta

      Convener: Prof. Richard Marchand (University of Alberta)
      • 253
        Anisotropic ion temperatures and ion flows adjacent to auroral precipitating electrons
        Large ion temperature anisotropies (temperature perpendicular to magnetic field larger than parallel to magnetic field) in narrow regions of enhanced ion flow have been identified by the Electric Field Instruments on board the Swarm satellites as a persistent feature of the high latitude midnight-sector auroral zone. These flow channels typically span less than 100 km latitudinally with ion flows of several kilometres per second. The largest observed temperature anisotropy ratios exceed the values predicted by currently used cross sections in theories of collisional heating in strong flows by a factor of 2. Coincident optical measurements from ground-base all-sky imagers indicate that these flow channels are immediately adjacent to regions of precipitating electrons, likely in the vicinity of the ionospheric projection of the open-closed boundary. We will be presenting ion velocity, ion temperature, and magnetic field measurements in and around these regions of enhanced ion flow from December 2013. The orbit of the Swarm satellites during this time result in measurements near the Harang discontinuity. The Electric Field Instruments on board the Swarm satellites are ideally suited for analysis of ion temperature anisotropy. The pearls-on-a-string configuration held by the Swarm satellites during these first weeks of the Swarm mission provides a unique opportunity to distinguish temporal from spatial variation in this dynamic region.
        Speaker: William Archer (University of Calgary)
      • 254
        Generation, dynamics, and decay of a polar cap patch
        The polar cap ionosphere, an important part of the solar wind-magnetosphere-ionosphere system, is formed by ionization of the neutral atmosphere by solar radiation and particle precipitation under internal transportation and chemical processes. The polar ionosphere is primarily driven by magnetospheric convection and neutral circulation, and undergoes structuring over a wide range of temporal and spatial scale sizes. This structuring is due to the interplay of mechanical forces, electrodynamics, and ionization chemistry. The most prominent and frequent structure of the polar cap ionosphere is the polar patch, which is defined as a region of enhanced F layer ionization distinguishable from the background electron density. Several theories, observations, and hypotheses on the generation and dynamics of these patches are available in the literature. However, a coherent understanding of patch formation is still lacking, mainly due to the lack of high spatial and temporal resolution observations. This is also compounded by our attention to more dramatic patch events. This presentation will focus on a less-dramatic patch event using observations from the Canadian High Arctic Ionospheric Network (CHAIN), in order to provide a coherent view of formation, dynamics, and decay of polar patches.
        Speaker: Dr Thayyil Jayachandran (University of New Brunswick)
      • 255
        Temporal and Spatial Evolution of Poynting Flux Measured with Swarm
        Small Scale Dynamics of Poynting Flux Measured With Swarm We present case studies of ionospheric Poynting flux using the instruments onboard the three ESA Swarm spacecraft. The three Swarm satellites each carry an Electric Field Instrument (EFI) that can be used to measure ion drift velocities. During the first months of the mission the satellites were in nearly circular, polar orbits at an altitude of 490 kilometers and were approximately 1000 kilometers from each other. During this time, they followed one after another in a pearls-on-a-string arrangement, separated by about one minute in time. This relatively close spatial formation allows comparisons to be done between electric field measurements on each satellite, revealing spatial and temporal structure. In this project we measure ionospheric Poynting Flux using each Swarm satellite. Cross correlation functions are calculated between measurements on each satellite and are used to determine the temporal and spatial scales of observed features. Acknowledgements: The EFIs were developed and built by a consortium that includes the University of Calgary, the Swedish Institute for Space Physics in Uppsala, and COM DEV Canada. The Swarm EFI project is managed and funded by the European Space Agency with additional funding from the Canadian Space Agency.
        Speaker: Mr Matthew Patrick (University of Calgary)
      • 256
        Small Scale Structuring in Electron Precipitation as seen by the ePOP Suprathermal Electron Imager
        Auroral arcs are known to be caused by electrons with keV energies interacting with the neutral atmosphere. However, there is much more to the aurora than auroral arcs. There is a wide range of phenomena that are grouped together as "diffuse aurora". Suprathermal electron precipitation (having energies between 1 eV and a keV) often contributes to the diffuse aurora. Much less is known about suprathermal electron precipitation than the higher energy precipitation. The ePOP Suprathermal Electron Imager (SEI),a high-time-resolution CCD-based detector capable of imaging electron velocity distributions, is currently being used to survey this type of precipitation. We will present observations of dispersed electron busts, where a burst of electron precipitation is dispersed over the distance from source to detector. We will also present observations of "inverse" electron dispersion, in which a low energy population of electrons increases in energy over time. This has not been reported in literature before. We present a simple model that could explain this phenomenon, and results from a simple simulation of it.
        Speaker: Taylor Cameron (University of Calgary)
      • 257
        Cusp Ion Upflows Observed by e-POP SEI and RISR-N: Initial Results
        Low-energy ion upflows associated with ion heating processes in the cusp/cleft and polar cap regions are investigated using conjunctions of the Enhanced Polar Outflow Probe (e-POP) satellite and the Resolute Bay Incoherent Scatter Radar (RISR-N) in June 2014 and February 2015. e-POP encountered the cusp/cleft ion fountain at 10-14 MLT and around 1000km altitude during these conjunction experiments. Such intermediate-altitude observations of ion upflow have been recorded only rarely by previous satellite missions and ground-based radars. The Suprathermal Electron Imager (SEI) onboard e-POP measured two-dimensional ion distribution functions with a frame rate of 100 images per second, from which high-precision energy and angle information of entering ions can be inferred. Field-aligned ion bulk flow velocities were estimated from the angle information with a resolution of the order of 25 m/s. The second moments of the ion distribution provide us with information on ion temperature, which was found to increase sharply in the region of cusp ion upflows in most cases. Also, ion composition information is available from ePOP’s ion mass spectometer (IRM). The ion upflow velocity reaches 2.5km/s in the first identified event on June 1st, 2014, during which the IRM indicated the dominant species as O+ (80%) and H+ (20%). We will compare the in situ measurements with RISR-N observations in order to further understanding of the three-dimensional structure of the cusp ion fountain.
        Speaker: Yangyang Shen (University of Calgary)
    • T3-4 Cosmic Frontier: Dark Matter III (PPD)/ Frontière cosmique: matière sombre III (PPD) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: Thomas Gregoire (Carleton University)
      • 258
        Status of the SuperCDMS and European Cryogenic Dark Matter experiments
        The SuperCDMS collaboration operates cryogenic germanium detectors to search for particle dark matter (WIMPs), so far at Soudan Underground Laboratory in Minnesota, US. The EURECA collaboration gathers EDELWEISS, a European collaboration also operating cryogenic germanium detectors, at the Laboratoire Souterrain de Modane, and CRESST who operate cryogenic scintillating detectors (CaWO4) at the Laboratori Nazionali del Gran Sasso, Italy, both with same goal of detecting primarily low mass WIMPs. Most recent progress of these searches will be described together with the planned common future at SNOLAB.
        Speaker: Dr Gilles Gerbier (Queens University)
      • 259
        New Pulse Processing Algorithm for SuperCDMS
        SuperCDMS searches for dark matter in the form of Weakly Interacting Massive Particles (WIMPs) with cryogenic germanium detectors. WIMPs interacting with atomic nuclei deposit energy in form of lattice vibrations (phonons) which propagate through the cylindrical Ge single crystal (75 mm diameter, 25 mm high) until they are absorbed by the phonon sensors covering part of the flat surfaces of the crystal. A fraction of the phonons are absorbed when they first reach the surface; a large fraction, however are reflected numerous times leading to a homogeneous distribution in the crystal. This leads to a pulse shape with an initial sharp pulse whose amplitude depends on the distance between the interaction side and the individual sensor, followed by a slow pulse which is identical for all sensors. Traditionally CDMS has used an optimal filter algorithm to extract energy information, but the different pulse shapes lead to a noticeable position dependence on the reconstructed energy. A modification of this algorithm de-weights the initial part leading to a considerably improved energy resolution. A combination of both methods has been used to determine energy and position information. We developed a new algorithm which accounts for the pulse shape by fitting two pulse templates simultaneously to each pulse, one for the position dependent sharp peak and one for the position independent slow pulse. This algorithm has the potential to improve the energy and position resolution while reducing the overall processing time. We will present a first study of the performance of this algorithm.
        Speaker: Mr Ryan Underwood (Queens University)
        Slides
      • 260
        Alpha particle backgrounds from the neck of the DEAP-3600 dark matter detector
        The DEAP-3600 dark matter detector at SNOLAB will search for scattering of weakly interacting massive particles from a 3600 kg liquid argon target. The liquid argon is held in a spherical vessel made from acrylic, with the highest standards of purity for both bulk acrylic and removal of surface activities. At the top of the vessel there is a neck opening to the cooling system, and alpha particles decays in this region can potentially introduce a background to the dark matter measurement. The steps to eliminate these alpha backgrounds will be presented, including details on the detector construction, radioactivity simulations, and analysis methods for measuring alpha backgrounds.
        Speaker: Dr James Bueno (University of Alberta)
        Slides
      • 261
        Optimizing the wavelength-shifter thickness for alpha suppression in the DEAP-3600 detector
        The DEAP-3600 experiment is a spherical dark matter detector searching for WIMPs by detecting scintillation light in a 3600 kg mass of liquid argon. Before the ultraviolet scintillation light passes through the optically clear acrylic vessel and light guides to the surrounding photomultiplier tubes, it must pass through a wavelength-shifting layer of tetraphenyl butadiene (TPB). Trace amounts of polonium 210 will contaminate the inner surface of the acrylic vessel as well as the TPB layer, and alpha particles resulting from its decay is expected to contribute background events to the WIMP signal. This talk will present the dependence of this background alpha signal on the thickness of the TPB layer, as well as the expected background events per 3 years of data taking at the optimized TPB thickness.
        Speaker: Derek Cranshaw (Queen's University)
        Slides
    • T3-5 Study of Neutrino Oscillations (PPD-DTP-DNP) / Études des oscillations de neutrinos (PPD-DPT-DPN) CAB 235

      CAB 235

      University of Alberta

      Convener: Zoltan Gecse (University of British Columbia (CA))
      • 262
        Status of Long-Baseline Neutrino Experiments
        The current generation of long-baseline neutrino oscillation experiments employ an off-axis $\nu_\mu$ (or $\bar{\nu}_\mu$) beam produced by the decay of pions created when a proton beam strikes a target. The beam is monitored at detector facilities near the production point before travelling hundreds of kilometres to a far detector. Aiming the beam centre slightly away from the far detector provides the off-axis configuration which selects a narrow energy band beam tuned to maximize the oscillation probability. The status of these experiments will be presented. The Tokai to Kamioka (T2K) experiment consists of a $\nu_\mu$ beam produced at the Japan Proton Accelerator Research Centre (J-PARC) in Tokai on the East coast of Japan, which is monitored by a suite of detectors before travelling 295 km to the Super-Kamiokande (SK) water Cerenkov detector. T2K has been in operation since 2010 and has been continually releasing new and exciting neutrino oscillation results. The most recent precision $\nu_\mu \to \nu_e$ appearance and $\nu_\mu$ disappearance oscillation measurements as well as initial results running the experiment in the $\bar{\nu}_\mu$ beam configuration will be presented. The NO$\nu\hspace{-0.11ex}$A experiment, utilizing the NuMI beam and a near detector at Fermilab and a far detector at a distance of 810 km, began operation in 2014. The current status of NO$\nu\hspace{-0.11ex}$A will also be shown.
        Speaker: Dr Nicholas Hastings (University of Regina)
        Slides
      • 263
        Electron Neutrino Cross Section Measurements at the T2K Off-Axis Near Detector
        T2K is a long baseline neutrino oscillation experiment in Japan, that targets the measurement of the mixing angle between the first and the third neutrino mass eigenstates ($\theta_{13}$) by looking for the appearance of electron neutrinos ($\nu_e$) in a beam of muon neutrinos ($\nu_\mu$), as well as a precision measurement for the mass difference between the the second and the third neutrino mass eigenstates ($\Delta m^2_{32}$) and their mixing angle ($\theta_{23}$). T2K can also probe anti-neutrino oscillation by looking for the appearance of anti-electron neutrinos ($\overline{\nu_e} $) in a beam of anti-muon neutrinos ($\overline{\nu_{\mu}} $). The experiment uses two detectors: a near detector at 280 m from the neutrino production target (in Tokai), and the far detector at 295 km, Super-Kamiokande (SK). The ND280 is a complex detector that includes a Pi0 Detector (P0D), two Fine Grained Detectors (FGDs), three Time Projection Chambers (TPCs), a Segmented Muon Range Detector (SMRD) and Electromagnetic Calorimeters (ECALs). The electron neutrino sample at ND280 is used for cross-section measurements, the search of sterile neutrinos and for the measurement of the $\nu_e$ component of the total neutrino flux. Obtaining a clean electron neutrino sample is complicated by the large muon neutrino background, and backgrounds due to external gamma rays. This talk will present the results of current electron neutrino cross section measurements at the T2K near detector. Status of work on anti-electron neutrino selection, and research on improving the selection of electrons, positrons, proton background, and background gamma samples using multivariate analysis techniques will be presented.
        Speaker: Fady Shaker (university of winnipeg)
        Slides
      • 264
        Constraining Oscillation Analysis Inputs at the T2K Near Detector
        The T2K long-baseline neutrino oscillation experiment is composed of a near detector at 280m and a far detector at Super-Kamiokande located 295 km from the neutrino beam in Tokai. The main oscillation analyses are performed using fits to the data collected at the far detector. These analyses depend on our ability to predict the event rates and energy spectra at the far detector, which in turn depend on cross-section and flux uncertainties. We use inputs from external data, such as MiniBooNE and MINER$\nu$A, as well as beam flux measurements to generate prior estimates of these uncertainties. T2K's near detector then provides a direct internal constraint on the convolution of the flux and cross-section, significantly reducing the uncertainties. This talk will discuss how data from the near detector on T2K is used to constrain the oscillation analysis inputs.
        Speaker: Christine Nielsen (University of British Columbia)
        Slides
      • 265
        Deep Core and PINGU - Studying Neutrinos in the Ice
        IceCube and its low energy extension DeepCore have been deployed at the South Pole and taking data since early 2010. Originally designed to search for high energy (on the order of PeV) events, IceCube has recently published the detection of the highest energy events ever recorded. At the same time, enhancements to the detector have been installed to focus on lower energy events. With a neutrino energy threshold of about 10 GeV, DeepCore allows IceCube to access a rich variety of physics including searching indirectly for WIMP dark matter and studying atmospheric neutrinos. A proposed new in-fill array, named PINGU, will continue to lower the threshold for neutrino detection. This will in turn provide the potential to study a great deal of new physics, including the determination of the neutrino mass ordering. This talk will discuss the PINGU detector and the new physics it makes available with a focus on the determination of the ordering.
        Speaker: Ken Clark (University of Toronto)
        Slides
      • 266
        Experimental test of the unitarity of the leptonic mixing (PMNS) matrix
        In the past decade, a remarkable progress has been made in the neutrino oscillation determining the lepton mixing (PMNS) angles, except for the CP violating phase delta_CP. The next step is to determine this remaining phase and then over-constraining the PMNS matrix to test its unitarity. Testing the unitarity is an effective way to search for physics beyond the standard model, as is demonstrated in the quark sector. For example, existence of right handed neutrinos or sterile neutrinos would violate the unitarity, and so does new interaction beyond the standard model. In this talk, I will describe the potential path towards testing the unitarity of the PMNS matrix. In particular, CP violation in the baseline length of solar neutrino oscillation provides key information, which the existing Super-Kamiokande data may even start to be sensitive. I will conclude with a prospect of the future experiments to make a stringent test of the unitarity of the PMNS matrix, showing that the accelerator and atmospheric neutrino measurement by Hyper-Kamiokande would take the central role.
        Speaker: Dr Akira Konaka (TRIUMF)
        Slides
    • T3-6 Nuclear Structure III (DNP) / Structures nucléaires III (DPN) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Jens Dilling (triumf/UBC)
      • 267
        Beta-decay from $^{47}$K to $^{47}$Ca with GRIFFIN
        Recent developments in many-body calculation methods have extended the application of *ab initio* interactions to medium-mass nuclei near closed shells. Detailed nuclear data from these isotopes are necessary to evaluate the many-body calculation methods and to test the predictive capacity of the interactions. $^{47}$Ca and $^{47}$K are each one nucleon removed from the doubly-magic nucleus $^{48}$Ca. The beta-decay from $^{47}$K to $^{47}$Ca has a reported half-life of 17.5 s and a $Q(\beta^-)$ value of 6643 keV. Transfer reactions from $^{48}$Ca have identified excited states of $^{47}$Ca throughout the available range of beta-decay $Q$-values, but the two published measurements of $^{47}$Ca populated by the beta-decay of $^{47}$K have only identified four states directly populated by beta decay. High-statistics beta-decay studies using modern high-efficiency, high-granularity detection systems can provide detailed information on level energies, beta-decay and gamma-ray branching ratios, as well as spin/parity assignments and transition mixing ratios through gamma-ray angular correlations. A recent experiment at TRIUMF-ISAC used the GRIFFIN spectrometer to investigate the levels populated by beta decay in more detail. A beam of surface-ionized $^{47}$K was provided by the TRIUMF-ISAC facility and implanted onto a mylar tape at the focus of the GRIFFIN spectrometer, where it decayed to $^{47}$Ca. The early implementation of the GRIFFIN spectrometer used in this experiment consisted of 15 close-packed HPGe clovers with 19% absolute full-photopeak efficiency for 1 MeV gamma rays. Beta detection was provided by ten of the plastic scintillators of SCEPTAR and internal electron conversion spectroscopy was possible with the five lithium-drifted silicon detectors of PACES. The intensity of the beam and the efficiency of the GRIFFIN spectrometer allow for the detection of gamma-ray transitions with small branching ratios, enabling the list of states populated by beta decay to be extended from previous publications. In addition, angular correlations between cascading gamma rays provide information about the spins and parities of states that are not currently included in the beta-decay level scheme. An overview of the experimental apparatus as well as a discussion of the results from preliminary analysis will be presented.
        Speaker: Dr Jenna Smith (TRIUMF)
      • 268
        Investigating the Structure of $^{46}$Ca through the $\beta^{-}$ Decay of $^{46}$K Utilizing the New GRIFFIN Spectrometer
        Due to its very low natural abundance of 0.004%, the structure of the magic nucleus $^{46}$Ca has not been studied in great detail compared to its even-even Ca neighbors. The calcium region is currently a new frontier for modern shell model calculations based on NN and 3N forces [1,2], so detailed experimental data from these nuclei is necessary for a comprehensive understanding of the region. Excited states in $^{46}$Ca have been identified previously by various reaction mechanisms, most notably from $(p,p')$ and $(p,t)$ reactions [3]. The low-lying structure has been investigated by two previous beta-decay experiments, with large discrepancies present between the reported decay schemes [4,5]. A recent beta-decay of $^{46}$K performed at TRIUMF's ISAC yield station obtained a new $T_{1/2}$ value of 96.303(79) s and identified 33 new gamma rays attributed to $^{46}$Ca [6]. However, since the ISAC yield station is not equipped with gamma-gamma coincidence capabilities the observed gamma rays were not placed into the decay scheme of $^{46}$Ca. In this experiment, using an early-implementation of the new GRIFFIN spectrometer located at TRIUMF-ISAC, a 9$\mu$A 500 MeV proton beam was impinged onto a uranium carbide target to induce spallation and fission reactions. Radioactive species were surface ionized and a high-resolution mass separator was used to select singly-charged $A$ = 46 ions only. The beam consisting almost entirely of $^{46}$K was implanted onto a Mylar tape at the center of the GRIFFIN array. The $^{46}$K source then populated the excited states of $^{46}$Ca through $\beta^{-}$ decay. The resulting gamma-rays were detected with the new GRIFFIN spectrometer, consisting of 15 HPGe clover detectors. The array also included SCEPTAR, an array of ten plastic scintillators mounted down-stream for $\beta$ particle detection, and PACES, an array of Si(Li) detectors used for the detection of conversion-electrons. The high-statistics data set obtained from this experiment makes it possible to extend the current level scheme, including the assignment of new transitions and levels. The spin and parity of excited states in $^{46}$Ca will be determined through a gamma-ray angular correlation analysis. Preliminary results from this experiment will be discussed. [1] J.D. Holt et al., Phys. Rev. C 90, 024312 (2014). [2] A.Ekstrom et al., Phys. Rev. Lett. 110. 192502 (2013). [3] J.Blachot, Nuclear Data Sheets 111, 717 (2010). [4] B. Parsa and G. Gordon, Phys. Lett. 2, 269 (1966). [5] M.Yagi et al., Laboratory Nucl. Sci., Tohoku Univ. 1, 60 (1968). [6] P.Kunz et al., Rev. Sci. Instrum. 85(5), 053305 (2014).
        Speaker: Ms Jennifer Pore (Simon Fraser University)
        Slides
      • 269
        The first GRIFFIN Experiment: An investigation of the $s$-process yields for $^{116}$Cd
        In adopted models for the $s$-process, it is assumed that helium shell flashes give rise to two neutron bursts at two different thermal energies $(kT\sim10$ keV and $kT\sim25$ keV). The contribution to the isotopic abundance of $^{116}$Cd from the higher temperature neutron bursts are calculated assuming thermal equilibrium between the ground state and the long-lived isomeric state of $^{115}$Cd. However, it is unknown if the thermal equilibrium between these states is present at the low temperature of the first burst. The presence of thermal equilibrium at low temperatures would significantly decrease the calculated $s$-process yields of $^{116}$Cd. To answer this question, we are searching for gateway levels at slightly higher excitation energy than the isomer in $^{115}$Cd that could be populated from the isomeric state via $(\gamma,\gamma^\prime)$ reactions within stars. Currently, the lowest potential gateway level at an excitation energy of 394 keV has only been observed to decay directly to the isomeric state in $^{115}$Cd. Nonetheless, the observation of this state decaying to the previously known 361 keV level via a weak 33 keV transition would provide a $\gamma$-ray cascade which would bypass the isomeric state. Thus, the observation of this decay would be a direct signature for the presence of thermal equilibrium during the lower temperature neutron burst. However, the direct measurement of a 33 keV transition is difficult due to the large low-energy $\gamma$-ray backgrounds observed in $\beta$-decay experiments. We therefore require high-efficiency $\gamma$-ray detection to indirectly observe this transition via $\gamma$-$\gamma$ coincidences of $\gamma$-rays cascading through this transition. In November 2014, the high-efficiency GRIFFIN HPGe spectrometer was commissioned at TRIUMF's Isotope Separator and Accelerator (ISAC). GRIFFIN is a state-of-the-art array consisting of 16 HPGe clovers, and boasts a large $\gamma$-ray efficiency of roughly 17% at 1 MeV. GRIFFIN also hosts a large suite of auxiliary detectors such as SCEPTAR, which is an array of 20 plastic scintillators designed for $\beta$-particle detection. In this first experiment, beams of $^{115}$Ag and $^{115}$Ag$^{\text{m}}$ were delivered to the GRIFFIN spectrometer equipped with SCEPTAR in order to search for these very-low-intensity $\gamma$-$\gamma$ coincidences following the $\beta$ decay of $^{115}$Ag into $^{115}$Cd. In this talk, results from this first GRIFFIN experiment will be presented.
        Speaker: Mr Ryan Dunlop (University of Guelph)
      • 270
        Gamma-Gamma Angular Correlation Measurements With GRIFFIN
        When a excited nuclear state emits successive $\gamma$-rays in a $\gamma-\gamma$ cascade, $X^{**} \rightarrow X^{*} + \gamma_{1} \rightarrow X + \gamma_{2}$ an anisotropy is found in the spatial distribution of $\gamma_{2}$ with respect to $\gamma_{1}$. By defining the direction of $\gamma_{1}$ to be the z-axis, the intermediate level, $X^{*} $, in general will have an uneven distribution of m-states. This causes an anisotropy in the angular correlation of the second $\gamma$-ray with respect to the first. The correlations depend on the sequence of spin-parity values for the nuclear states involved as well as the multipolarities and mixing ratios of the emitted $\gamma$-rays. These angular correlations are expressed by the $W(\theta)$ function: \begin{center} $W(\theta) = 1 + \sum\limits_{k = even}^{2L} a_{k}P_{k}(cos\theta)$ \end{center} where $L$ is the lowest multipole order of the emitted $\gamma$-rays and the $a_{k}$ are coefficients\part{title} for all of the $P_{k}(cos\theta)$ Legendre polynomials. Angular correlations can be used for the assignment of spins and parities to nuclear states and thus provide a powerful means to elucidate the structure of nuclei away from stability through $\beta-\gamma-\gamma$ coincidence measurements. In order to explore the sensitivity of the new 16 clover-detector GRIFFIN $\gamma$-ray spectrometer at TRIUMF-ISAC to such $\gamma-\gamma$ angular correlations, and to optimize its performance for these measurements, we have studied a well known $4^{+}\rightarrow 2^{+}\rightarrow 0^{+}$ $\gamma-\gamma$ cascade from $^{60}$Co decay through both experimental measurements and Geant4 simulations. Results of these investigations will be presented in this talk.
        Speaker: Mr Andrew MacLean (University of Guelph)
        Slides
      • 271
        High-Precision Half-Life Measurements for the Superallowed $\beta^+$ emitter $^{10}$C
        High precision measurements of superallowed Fermi beta transitions between 0$^+$ isobaric analogue states allow for stringent tests of the electroweak interaction described by the Standard Model. In particular, these transitions provide an experimental probe of the unitary of the Cabibbo-Kobayashi-Maskawa (CKM) matrix, the Conserved-Vector-Current (CVC) hypothesis, as well as set limits on the existence of scalar currents in the weak interaction. Half-life measurements for the lightest of the superallowed emitters are of particular interest as it is the low-$Z$ superallowed decays that are most sensitive to a possible scalar current contribution. The half-life of $^{10}$C can be measured by directly counting the $\beta$ particles or measuring the $\gamma$-ray activity following $\beta$ decay. Previous results for the $^{10}$C half-life measured via these two methods differ at the 1.5$\sigma$ level, prompting simultaneous and independent measurements of the $^{10}$C half-life using both techniques. Since $^{10}$C is the lightest nucleus for which superallowed $\beta$ decay is possible, a high precision measurement of its $ft$ value is essential for obtaining an upper limit on the presence of scalar currents in the weak interaction. Measurements of the $^{10}$C half-life via both gamma-ray photo-peak and direct beta counting were performed at TRIUMF's Isotope Separator and Accelerator (ISAC) facility using the 8$\pi$ spectrometer and a $4\pi$ gas proportional $\beta$ counter at the ISAC General Purpose Station. The 8$\pi$ $\gamma$-ray spectrometer consists of 20 High Purity Germanium (HPGe) detectors as well as the Zero Degree $\beta$ detector, a fast plastic scintillator located at the end of the beam line within the 8$\pi$. This presentation will highlight the importance of these measurements and preliminary half-life results for $^{10}$C will be presented.
        Speaker: Michelle Dunlop (University of Guelph)
      • 272
        The First Radioactive Beam at GRIFFIN: $^{26}$Na for Decay Spectroscopy
        GRIFFIN (Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei) was installed at the TRIUMF-ISAC-I facility during 2014 and represents a major upgrade to the 8$\pi$ spectrometer which operated at ISAC for the past decade. With an array of 16 large-volume hyper-pure germanium (HPGe) clover detectors, instrumented with a state-of-the-art digital data acquisition system, the array promises to bring a new level of sensitivity to decay spectroscopy experiments. GRIFFIN is used to investigate a wide variety of nuclear properties relevant to nuclear structure, nuclear astrophysics, and fundamental symmetries using stopped radioactive beams from ISAC and the future ARIEL facility. The most exotic nuclei produced at these facilities are generally produced with the lowest intensity. Additionally, in modern studies of the decay of intense radioactive beams, it is often the weakest decay branches which are of the greatest interest. The high efficiency of the GRIFFIN spectrometer makes spectroscopy possible in both situations. GRIFFIN was commissioned in the fall of 2014 using a radioactive $^{26}$Na beam produced from impinging 500 MeV protons onto a silicon-carbide (SiC) target. The $^{26}$Na beam was then implanted into a movable tape at the central focus of the array. The auxiliary detector SCEPTAR (an array of 20 plastic scintillator paddles) was used for beta-tagging while the GRIFFIN spectrometer itself was used for the detection of gamma radiation. A previous experiment, also studying the decay of $^{26}$Na, ran under similar conditions using the 8$\pi$ spectrometer at TRIUMF in 2004. Results highlighting the performance of the GRIFFIN array as well as the structure of the $^{26}$Mg daughter will be presented.
        Speaker: Nikita Bernier (TRIUMF)
        Slides
    • T3-7 Panel on Women in Phyiscs (CEWIP) / Table ronde sur les femmes en physique (CEFEP) CCIS L1-160

      CCIS L1-160

      University of Alberta

      Convener: Shohini Ghose (urn:Facebook)
      • 273
        Panel Discussion on Women in Physics
        Moderator: Shohini Ghose, Wilfrid Laurier University Panellists: Sara Seager (MIT), Adriana Predoi-Cross (University of Lethbridge) and Wendy Taylor (York University)
    • T3-8 Advanced Instrumentation at Major Science Facilities: Detectors I (DIMP) / Instrumentation avancée dans des installations scientifiques majeures: détecteurs I (DPIM) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Kirk Michaelian (Natural Resources Canada)
      • 274
        Advanced Instrumentation at TRIUMF
        TRIUMF operates the Isotope Separator and Accelerator (ISAC) rare isotope facility as well as the Centre for Molecular and Materials Science (CMMS), which uses muons and isotopes. The ISAC facility comprises 18 state of the art experiments for experimental programs in nuclear structure, nuclear astrophysics, and fundamental symmetries. CMMS features several state-of-the-art set-ups for muon spin rotation (MuSR) experiments as well as stations for beta detected NMR and NQR using rare isotopes. Most recently, the new electron linac, a cutting-edge superconducting RF accelerator and part of the Advanced Rare Isotope Laboratory (ARIEL), has just been commissioned. In addition to these user facilities TRIUMF carries out developments for a number of particle physics detector projects, including the ATLAS detector at the LHC, the long-baseline neutrino experiment T2K, and the nEXO next generation double beta decay project. The presentation will provide an overview of the facility and highlight selected projects.
        Speaker: Prof. Reiner Kruecken (TRIUMF)
        Slides
      • 275
        Development and simulations of the CANREB RFQ buncher and cooler at the TRIUMF facility
        TRIUMF’s new Advanced Rare IsotopE Laboratory (ARIEL) is the up and coming producer of rare isotope beams for nuclear science in Canada. It will triple the number of beamlines available to both of the (rare) Isotope Separator and Accelerator (ISAC) facilities, and will expand their range of available isotopes. An overview of ARIEL and the CANadian Rare-isotope facility with Electron-Beam ion source (CANREB) will be given with the focus on the CANREB Radio Frequency Buncher and Cooler (CANREB RFQ). The theory behind the operation of RFQs will be discussed as well as the results of systematic studies done via simulation to optimize the injection and extraction ion optics. The RFQ is expected to provide bunching and cooling of beams with masses in the range of 15 to 250 amu utilizing two separate RF circuits of different frequencies to span this large range efficiently. Comparisons will be made via simulations between both the TITAN RFQ (located at TRIUMF) as well as the BECOLA RFQ (located at MSU) after which the CANREB’s RFQ novel electrode structure is modeled.
        Speaker: Mr Jeff Bale (TRIUMF)
        Slides
      • 276
        Photodetection with SiPM in particle physics and materials science
        Pixelated Geiger-mode avalanche photo-diodes also called silicon photo-multipliers (SiPMs) are replacing traditional vacuum photo-multiplier tubes (PMTs) in numerous applications in subatomic physics, medical imaging and condensed matter. They have several advantages being insensitive to magnetic field, having higher efficiency, more uniform gain, and being more compact. However, they still cannot compete with PMTs for application requiring large areas of photo-detection at room temperature. We will describe their characteristics and performances and show a few specific applications in particle physics, condensed matter and medical imaging.
        Speaker: Fabrice Retiere (TRIUMF)
        Slides
      • 277
        The Electrodynamometer of the McPherson Collection of Scientific Instruments
        The Weber electrodynamometer is an instrument used to measure the absolute value of electric power (or current if one knows the voltage). It works by measuring the mechanical torque between two pairs of coils induced by the current in the coils. This is one of the first research instrument bought in 1895 by the newly created McGill Physics Department for 177£. McGill College apparatus originally constructed by Messrs. NALDER from London was intended to be an exact duplicate of the apparatus in the Cavendish Laboratory at Cambridge. When received it did not meet specifications and had to be completely rebuilt by an undergraduate student under the supervision of Prof. Hugh Callendar. After rebuilding it had an absolute precision of the order of one part in a thousand. The repair and operation of the instrument will be described in details.
        Speaker: Jean Barrette (McGill University)
    • T3-9 Molecular Biophysics (DMBP) / Biophysique moléculaire (DPMB) CAB 239

      CAB 239

      University of Alberta

      Convener: Maikel Rheinstadter (McMaster University)
      • 278
        Watching proteins fold: capturing the conformational diffusion of single molecules during structural self-assembly
        The self-assembly of intricate structures by proteins is a complex process involving myriad degrees of freedom. Such “folding” is usually described in terms of a diffusive search over a multi-dimensional energy landscape in conformational space for the lowest-energy structure. The diffusion coefficient, *D*, encodes the rates at which microscopic motions occur during folding and is thus of fundamental interest, but it is very difficult to measure. I show how *D* can be determined from measurements of single proteins folding and unfolding under tension in optical tweezers. By reconstructing the energy landscape for folding from the statistics of the single-molecule trajectories, *D* can be found using classic kinetic rate theories. More sensitive measures of *D* can be obtained by measuring the “transition time” required for the molecule to transit the energy barrier separating two structures. Using the folding of the protein PrP, which forms incorrect structures that lead to “mad cow” disease, as an example, *D* is seen to be orders of magnitude faster for the correct structure of the protein than for incorrect structures. Indeed, the incorrect structures form sufficiently slowly that the path the protein follows during the structural change—never before observed directly for any protein—can now be seen. Finally, I discuss how the properties of such transition paths can be used to show that the multi-dimensional problem of protein folding can be reduced quantitatively to one-dimensional diffusion.
        Speaker: Michael Woodside (University of Alberta)
      • 279
        Coarse-Grained computer simulations of Alzheimer’s beta-amyloid peptides, using the Mercedes-Benz Hydrogen Bond Potential
        Protein aggregation is a medically relevant phenomenon that can lead to protein-folding diseases such as Alzheimer’s and Prion’s. The aggregation process is largely determined by hydrogen bonds (HB), involving hundreds of peptides, over a period of days or even months. This rules out molecular dynamics (MD) simulations of all-atom protein models in explicit solvents. However, coarse-grained models of protein aggregation must accurately represent HB. This work considers the coarse-grained model used by Head- Gordon and coworkers to study the beta-amyloid (Aβ) peptides that forms plaques in Alzheimer’s diseases [1]. The model represents one amino-acid residue by a single bead, and used the Mercedes-Benz (MB) model to describes backbone HB. This has been adapted to study residue 25 to 35 of the peptide, Aβ_{25-35}, which is believed to be the most toxic stretch of Aβ. Preliminary work has obtained data on Langevin dynamics of 100 Aβ_{25-35} in a 100A ×100A ×100A box. The model peptides will be immersed in the MB water model of Dias and coworkers [2], used previously to study cold denaturation of proteins. The final model will be used to accurately identify the structure of Aβ intermediates believed to the neurotoxin agents in Alzheimer’s disease. [1] Hui, Fawzi, Head-Gordon, Proteins 70, 626 (2008) [2] Dias, Alla-Nissila, Grant, Kartunnen, J. Chem. Phys. 131, 054505 (2009)
        Speaker: Dr Apichart Linhananta (Lakehead University)
      • 280
        The Formation of Alzheimer's Plaques in Synthetic Membranes
        Alzheimer’s disease is a type of dementia that affects memory, thinking, and behaviour. One of the hallmarks of the disease is the formation of neurotoxic senile plaques, primarily consisting of amyloid-β peptides. Despite their importance for the pathogenesis of the disease, little is known about the properties of these plaques and the process by which they form. We developed a model system to study the formation and properties of Alzheimer’s plaques in-vitro. Synthetic anionic lipid membranes with brain-like composition were prepared that included different concentrations of the amyloid-β(25-35), the transmembrane segment of the full 42 amino acid long peptide. The systems were prepared as multi-lamellar membranes supported on silicon chips. We investigated size, density and molecular properties of these plaques using optical microscopy and X-ray diffraction. At concentrations of 3mol%, the peptides were dispersed in the membranes, but at concentrations of 10mol% and 20mol%, peptide aggregates were observed. Plaques formed from amyloid-β aggregates were typically around 12 to 13 micrometers in diameter. With increasing peptide concentration, the density of small plaques increased, however, their size stayed approximately constant. The aggregates were found to form inside the membranes and to coexist with the membrane structure. We used X-ray diffraction to determine the molecular structure of the membranes and peptide structure. At concentrations of 3mol%, only the alpha-helix signal was detected whereas in the 10mol% and 20mol% samples, both alpha-helix and beta-sheet signals were detected. The preparation of synthetic Alzheimer’s tissue is a milestone for the in-vitro testing of anti-Alzheimer’s drugs before they go into clinical studies. By preparing membranes of different composition, such as saturated and unsaturated lipids, cholesterol and hormones, quantitative information about plaque formation can be obtained.
        Speaker: Jennifer Tang (McMaster University)
        Slides
      • 281
        Alzheimer's Disease Amyloid Beta(25-35): An Oligomeric Aggregation Simulation From Monomers to Ordered Filaments
        Amyloid Beta (A$\beta$) plaques have long been correlated with Alzheimer's disease; however, efforts made to link the plaques to pathogenic effects or utilize them for diagnostic purposes have not been very fruitful. Modern investigations point to peptide intermediate structures or their oligomers as likely candidates for the toxic agents, yet much remains unknown about the aggregation life cycle from monomers to aggregated ordered filament structure. From a simulation standpoint, this is generally difficult due to the high residue count and long time frames involved in such investigations. Fortunately, in the case of Alzheimer's disease, there is a fragment of the A$\beta$ peptide, A$\beta_{25-35}$ which has a short residue length, aggregates rapidly, and is highly pathogenic[1], making it particularly well suited for biophysical simulation. Our work investigates A$\beta_{25-35}$ utilizing a molecular dynamics simulation and course-grained _C$\alpha$ model based on that presented by Yap et al. in [2] which includes hydrogen bond pairing to stabilize the secondary structure. The entire aggregation process is explored from random-coil monomers, through formation of unordered intermediate oligomeric states, and into ordered filament structure. Utilizing standard cluster criterion, the nucleation free-energy landscape for A$\beta{25-35}$_ as a function of the number of peptides and hydrogen bond count between peptides is mapped and nucleation barriers are determined as in [3]. Also thermodynamic and kinetic measures are determined. The determination of these factors is the necessary first step to conducting future investigations involving solvents and in the presence of surfaces. [1] J. Biosci. 34(2), pp. 293–303, 2009 [2] Proteins 70, pp. 626-638, 2008 [3] PRL 101 (25), 258101, 2008
        Speaker: Robert Girardin (Lakehead University)
      • 282
        Kinetics of Chain Motions within the disordered eIF4E-BP2 protein
        Intrinsically disordered proteins (IDPs) play critical roles in regulatory protein interactions. Cap-dependent translation initiation is regulated by the interaction of eukaryotic initiation factor 4E (eIF4E) with disordered eIF4E binding proteins (4E-BPs) in a phosphorylation dependent manner. Fluorescence correlation and time-resolved anisotropy spectroscopies were used to detect and assess sequence-specific local chain motions of 4E-BP2 upon phosphorylation and upon binding to eIF4E. Nanosecond scale dynamics of 4E-BP2 was observed by correlation spectroscopy, and it was tentatively assigned to intrachain contact formation process. Our data suggests that multi-phosphorylation of the protein slows down the proximal chain motions and also modulates the kinetics of distal regions. Rotational correlation times and wobbling cone angles extracted for different segments of the 4E-BP2 protein provide a quantitative picture of the rigidity of the protein at different sites and can also be used as a probe to evaluate the binding to eIF4E. We show that the region near the position 73 in the sequence has highest binding affinity to eIF4E. Data acquired under high denaturant conditions, in 6 M guanidinium chloride, indicates that this IDP behaves differently than a random coil model.
        Speaker: Zhenfu Zhang (University of Toronto)
    • Department Leaders Business Meeting / Réunion d'affaires des directeurs de départements Athabaska Hall, Heritage Room (#227)

      Athabaska Hall, Heritage Room (#227)

      University of Alberta

      Convener: Barbara Frisken (Simon Fraser University)
    • CJP Editorial Board Meeting / Réunion du comité de rédaction de la RCP The Hardware Grill 9698 Jasper Avenue Edmonton, AB T5H 3V5 780.423.0969 www.hardwaregrill.com email@hardwaregrill.com

      The Hardware Grill 9698 Jasper Avenue Edmonton, AB T5H 3V5 780.423.0969 www.hardwaregrill.com email@hardwaregrill.com

      Convener: Michael O. Steinitz (St. Francis-Xavier University)
    • Science Policy: Where do you fit? / Politique scientifique : où vous situez-vous? CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Christopher Pugh (University of Waterloo)
      • 283
        The 2018 Shutdown of the NRU reactor
        The Canadian federal government recently announced its decision to shut down the NRU reactor in 2018. The National Research Universal (NRU) reactor commenced operation in 1957, to provide neutrons for several missions simultaneously, including the production of neutron beams to support fundamental experimental research on solids and liquids. Today, the Canadian Neutron Beam Centre manages six thermal neutron beam lines at the NRU reactor, and sustains a team of scientific and technical experts who enable collaborative research projects to be performed effectively by students and scientists from over 30 Canadian universities, as well as over 100 foreign institutions from about 20 countries. This presentation will provide key details of the current situation, to inform CAP Science Policy, in case some response is considered about the imminent loss of a major Canadian resource for resaerch in condensed matter physics.
        Speaker: John Root (Canadian Nuclear Laboratories)
      • 284
        How physicists can have a stronger voice in Ottawa
        How can physicists have a stronger voice in government? We should be regularly posing this question before government budget decisions, before funding deadlines for scientific projects or infrastructure loom. Scientists in general, not to mention physicists, are not represented in large numbers in the country’s legislatures, nor are they commonly sighted in the halls and offices of Parliament, nor are they particularly engaged in politics, compared to some other professions or groups. The speaker will outline some ideas for the audience to act upon, based on his personal experience, which may help to increase the visibility and influence of scientists in the world of politics and government.
        Speaker: Ted Hsu (MP, Kingston and the Islands)
    • Break / Pause CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

      Edmonton, AB
    • Physics Career Paths: Stories of where a Physics Education can lead / Cheminements de carrière en physique: où des études en physique pourraient vous mener CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Christopher Pugh (University of Waterloo)
      • 285
        Inelastic Collisions Outside Academe: Alternate Careers for Physicists
        Many physicists find rewarding careers outside universities, in industry and government service. Gary Albach has collected paycheques from all three sectors and shares job-seeking tips plus the terrors and challenges of the inelastic collisions within his career as a “lapsed physicist”.
        Speaker: Dr Gary Albach (Former President and CEO, Alberta Innovates – Technology Futures)
      • 287
        Panel / Round-Table Discussion
        (Albach, MacFarlane, Hsu)
    • Post-workshops Meet & Greet CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

      Conveners: Adam Sarty (Saint Mary's University), Kristin Poduska (Memorial University of Newfoundland)
    • CNILC Breakfast Meeting / Réunion du comité de liaison national canadien de l'UIPPA CCIS 4-285

      CCIS 4-285

      University of Alberta

      Convener: Jens Dilling (triumf/UBC)
    • Exhibit booths open 08:30-16:00 / Salle d'exposition ouverte de 08h30 à 16h00 CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • W1-1 Carbon-based materials (DCMMP) / Matériaux à base de carbone (DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Rachel Wortis (Trent University)
      • 288
        Chiral symmetry breaking and the quantum Hall effect in monolayer graphene
        When graphene is placed in a strong magnetic field it exhibits quantum Hall states at fillings that can be predicted by taking into account the relativistic form of the low-energy electronic excitations and ignoring interactions between electrons. However, additional quantum Hall states are observed at filling fractions $\nu$ = 0 and $\nu$ = $\pm$1 that are not explained within a picture of non-interacting electrons. We propose that these states arise from interaction induced chiral symmetry breaking orders. We argue that when the chemical potential is at the Dirac point, weak onsite repulsion supports an easy-plane antiferromagnet state, which simultaneously gives rise to ferromagnetism oriented parallel to the magnetic field direction, whereas for $|\nu|$=1 easy-axis antiferromagnetism and charge-density-wave order coexist. We perform self-consistent calculations of the magnetic field dependence of the activation gap for the $\nu$ = 0 and $\nu$ = 1 states and obtain excellent agreement with recent experimental results. Funding: Supported by NSERC Reference: B. Roy, M. P. Kennett, and S. Das Sarma, Phys. Rev. B **90**, 201409(R) (2014).
        Speaker: Prof. Malcolm Kennett (Simon Fraser University)
        Slides
      • 289
        Interfacing organic and carbon-based nanomaterials towards their applications in sustainable energy
        From the 1996 Nobel Prize for Chemistry, recognizing the synthesis of fullerene, to the 2010 Nobel Prize for Physics, awarded to the discovery of graphene, carbon-based nanomaterials have evolved into one of the hottest area in materials science. Utilization of large-area graphene thin films as transparent conductors in solar cells and energy-efficient light emitting devices may take significant advantage of a deeper understanding of their electronic and optical properties at the nanoscale. Applications exploiting the extremely high thermal conductivity of these materials are also emerging. A common denominator between many application-oriented graphene-based thin films is in the necessity of understanding their properties when they are interfaced with organic materials, including conducting polymers, organometallic nanoclusters and small polyaromatic molecules. In this presentation, I will review what our group has learned on the physical properties of graphene laminates, graphene-organic nanocomposites and graphene-based organic solar cells. Although all of these properties are reminiscent of the fundamental physics of individual graphene layers, a number of other concepts, related to their nanocomposite nature, are required to design large-area graphene thin films suitable for practical uses.
        Speaker: Prof. Giovanni Fanchini (The University of Western Ontario)
      • 290
        Third Harmonic Terahertz Response Optimization of Doped Monolayer Graphene
        Due to the linear dispersion of graphene, it has recently been predicted that third harmonic generation should be observed in monolayer graphene [1]. Although recent experiments have demonstrated third harmonic generation in a 45-layer thick sample [2], there has been no indication of harmonic generation in monolayer graphene [3]. To understand why this is the case and to try to maximize the third harmonic, it is important to investigate the parameters that are mostly affecting the third harmonic response. In this work, we employ a model that we developed recently [4] based on density-matrix formalism in the length gauge to calculate the nonlinear terahertz (THz) response of doped monolayer graphene and examine the effects of the incident field amplitude, the Fermi level and the scattering time on third harmonic generation. In all cases studied here, there is an optimum Fermi energy for a given scattering time. We consider three different Fermi-energy-dependent scattering mechanisms: phonon, long-range impurity, and short-range impurity. We find that the optimized Fermi energy increases as the scattering time increases. This arises because when the Fermi level is increased, there is an increase in the number of carriers, which in turn leads to a larger current density. In principle, this could lead to a stronger nonlinearity in the transmitted field. However, when the Fermi level is high and the scattering time is too short, only a relatively small fraction of the carriers are driven in k-space by the field to the one side of the Dirac point. As it is the asymmetry in the k-space distribution that yields current clipping, the degree of nonlinearity is limited when the Fermi energy is too high. Therefore, using too high or too low Fermi level will result in a decrease in third harmonic response. We thus find that the Fermi energy and the scattering time of the sample are crucial factors if one is to observe high harmonics in monolayer doped graphene. For a sample that is dominated by phonon scattering, for a field amplitude of 75 kV/cm, we obtain an optimized third harmonic field amplitude that is 1.6% of the amplitude of the transmitted fundamental. Experimentally, this level should be measurable using current detection techniques such as the one reported in Ref. [5] where a dynamic range of 90 dB is reported by measuring 1000 scans that were taken in less than a minute. References 1. S. A. Mikhailov, Microelectronics Journal 40, 712 (2009). 2. P. Bowlan, E. Martinez-Moreno, K. Reimann, T. Elsaesser, and M. Woerner, Phys. Rev. B 89, 041408 (2014). 3. M. J. Paul, Y. C. Chang, Z. J. Thompson, A. Stickel, J. Wardini, H.Choi, E.D.Minot, T.B.Norris, and Y.-S.Lee, New J. Phys. 15, 085019 (2013). 4. I. Al-Naib, J. E. Sipe, and M. M. Dignam, Phys. Rev. B. 90, 245423 (2014). 5. N. Vieweg, F. Rettich, A. Deninger, H. Roehle, R. Dietz, T. G ¨ obel, and M. Schell, J. Infrared, Millimeter, Terahertz Waves 35, 823 (2014).
        Speaker: Prof. Marc Dignam (Queen's University)
      • 291
        Investigation of the interaction between the single walled carbon nanotube and conjugated oligomers using various dispersion correction DFT methods
        The area of carbon nanotubes (CNT)-polymer composites has been progressing rapidly in recent years. Pure CNT and CNT-polymer composites have many useful (industry related) properties ranging from good electrical conductivity to superior strength. However the full potential of using pure CNTs has been severely limited because of complications associated with the dispersion of CNTs. CNTs tend to entangle with each other forming materials that have properties that fall short of the expectations. The goal of this work is to enhance the understanding as to which type of conjugated oligomers is best suited for the dispersion of single walled CNTs (SWCNTs). For this purpose, various methods of dispersion corrected density functional theory (DFT-D/ B97D, /WB97XD, /CAM-B3LYP) have been used to investigate the interaction between the SWCNT and the fluorene based oligomers with different end groups (aldehyde (ALD) and dithiafulvenyl (DTF)). We investigate the effect of intermolecular interactions on the structure, polarity and energetics of the oligomers. Our results indicate that DTF ended oligomers tend to stretch along the nanotube (i.e. they lie parallel to it). On the other hand, ALD ended oligomers tend to lie across the nanotube. As a result of this structural difference, our results also indicate that, DTF ended conjugated oligomers become somewhat more polarized than ALD ended oligomers in the presence of the SWCNT and the binding energy is higher for DFT ended than ALD ended oligomers without side chain.
        Speaker: Mr Mohammad Zahidul Hossain Khan (Memorial University)
    • W1-10 Quantum Optics and Cavity QED (DAMOPC) / Optique quantique et ÉDQ en cavité (DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Chitra Rangan (University of Windsor)
      • 292
        High-fidelity single-shot Toffoli gate via quantum control
        A single-shot Toffoli, or controlled-controlled-NOT, gate is desirable for classical and for quantum information processing. The Toffoli gate alone is universal for reversible computing and, accompanied by the Hadamard gate, are universal for quantum computing. The Toffoli gate is a key ingredient for (non-topological) quantum error correction. Currently Toffoli gates are achieved by decomposing into sequentially implemented single- and two-qubit gates, which requires much longer times and yields lower overall fidelities compared to a single-shot implementation. We develop a quantum-control procedure to directly construct single-shot Toffoli gates and devise a scheme for three nearest-neighbor-coupled superconducting transmon systems that should operate with 99.9% fidelity under realistic conditions. The gate is achieved by a non-greedy quantum control procedure using our enhanced version of the Differential Evolution algorithm. arXiv:1501.04676
        Speaker: Barry Sanders (University of Calgary)
      • 293
        Cavity-induced spin-orbit coupled Bose-Einstein condensation: A new approach for exploring cold atoms
        The atom-photon interaction is significantly amplified when the radiation field is confined inside a high-finesse cavity, resulting in a complex, coupled dynamics of the quantized matter and radiation fields. This coupled dynamics in turn mediates long-ranged interactions between atoms. Here we demonstrate how to simultaneously induce spin-orbit (SO) coupling and long-ranged interactions in a Bose-Einstein condensation (BEC) using two counter-propagating modes of a ring cavity. The interplay between the standard two-body and cavity-mediated interactions determines the ground state and elementary excitations of the SO-coupled BEC. The ground state is either a plane wave or stripe phase, where in the latter case the density exhibits spatial modulations along the SO coupling direction. This opens up a possible new experimental approach for exploring quantum gases by tuning cavity parameters instead of using Feshbach resonance techniques.
        Speaker: Farokh Mivehvar (University of Calgary)
        Slides
      • 294
        The effect of off-resonant excitation on intensity-intensity correlation spectra in three-level, lambda systems
        Developing methods for the detection of single molecule interacting with the environment has been a large area of research. These methods are quite varied in their execution and include antigen binding, surface plasmon resonance, fluorescence among many others. These methods all take advantage of the fact that molecular processes often change how a substrate interacts with light when a certain molecule is bound to it. With this in mind, we investigate if energy level changes of a fluorescent molecule due to ambient interactions can be detected by monitoring the two-time intensity-intensity correlation spectrum of the molecule when driven by electromagnetic waves. As these correlations depend on the magnitude of detuning in the driving excitation, if the two-time intensity-intensity correlation spectrum were to be continuously monitored for a target transition in a three-level system, any changes that occur in the correlation spectrum could used to determine if the energy levels have changed and if any interactions have taken place.
        Speaker: Christopher DiLoreto (University of Windsor)
      • 295
        Entangled photon triplets: a new quantum light source and a test of nonlocality
        Entanglement is required for most applications in quantum information science. In optics, the most widespread source of entangled photon pairs is the nonlinear optical process of parametric down-conversion. Through this process, single high energy pump photons are converted into pairs of lower energy photons. In the first part of my talk I will describe our realization of cascaded parametric down-conversion, a sequence of two downconversion that can produce photon triplets, a longstanding goal of the quantum optics community. I will describe our experiments to detect the novel form of genuine three-photon energy-time entanglement produced through this process and the direct production of polarization Greenberger-Horne-Zeilinger states. In addition to their importance in quantum technologies, entangled photons can be used to perform fundamental tests of nature, such as ruling out local hidden variable descriptions. In the second part of my talk, I will discuss our experimental test of Mermin's inequality: a bound on the strength of correlations between three particles imposed by such models. We have for the first time closed the locality loophole in such a test by distributing three-photon entanglement over long distances using free-space optical links to causally disconnected locations. These results demonstrate the experimental requirements for implementing practical three-party quantum communication protocols (joint work with Thomas Jennewein).
        Speaker: Prof. Kevin Resch (University of Waterloo)
    • W1-2 Soft Condensed Matter and Soft Interfaces (DMBP-DCMMP) / Matière condensée molle et interfaces molles (DPMB-DPMCM) CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Maikel Rheinstadter (McMaster University)
      • 296
        Optimal control of microscopic nonequilibrium systems
        Molecular machines are protein complexes that convert between different forms of energy, and they feature prominently in essentially any major cell biological process. A plausible hypothesis holds that evolution has sculpted these machines to efficiently transmit energy and information in their natural contexts, where energetic fluctuations are large and nonequilibrium driving forces are strong. Toward a systematic picture of efficient, stochastic, nonequilibrium energy and information transmission, I address two related fundamental questions in nonequilibrium statistical mechanics: How do we predict the response of molecular-scale soft-matter systems to rapid nonequilibrium perturbations? And how do we identify the perturbations that most efficiently (yet rapidly) carry such a noisy system from one state to another? These abstract theoretical considerations have fairly immediate consequences for the design of single-molecule biophysical experiments, and potential implications for the design principles of energetically efficient yet stochastic molecular machines.
        Speaker: David Sivak (Simon Fraser University)
      • 297
        OMCVD AuNP Grown on Polymer Substrates: An approach Towards Mass Fabrication of Biosensors
        Organometallic chemical vapour deposited (OMCVD) gold nanoparticles (AuNPs) can be successfully used for biosensing. For the sensing mechanism an absorption feature, the localized surface plasmon resonance (LSPR), is implemented. Typically in this bio-sensing approach is monitoring the changes in the peak position of the LSPR via absorption spectroscopy during a highly specific binding reaction in real time. For this purpose a recognition site is immobilized on the nanoparticle via sulphur chemistry. The target molecule then recognises its host molecule and binds to it changing the dielectric constant of the layer on the AuNP which is detected by the LSPR. However, if the AuNPs are only loosely connected to the substrate they tend to form 2D clusters on the surface of the substrate as soon as a liquid comes into contact with them and then they deliver a false, irreversible shift in the LSPR. Therefore only AuNPs which are stably immobilized on a transparent substrate can be used for sensing purposes. In a first successful attempt we have used the sparsely available polar –NH groups of a monolayer of hexamethyldisilazane (HMDS) covalently attached to glass substrates to nucleate and grow stable AuNPs with the (trimethylphospine)methylgold ((CH3)3P]AuCH3) precursor. Now we present stable OMCVD AuNPs on oxygen plasma treated polystyrene, stepping towards technology allowing mass fabrication of AuNP-substrates. The polar -OH groups forming during the oxygen plasma process serve as nucleation sites for the AuNPs. The optimum conditions of the plasma treatment are determined: how to achieve the largest possible amount of –OH groups without changing the optical quality of the polymer. The shift in the LSPR, the bulk sensitivity of the AuNPs and first bio-sensing experiments with the biotin-streptavidin system are presented.
        Speaker: Prof. Silvia Mittler (University of Western Ontario)
      • 298
        In vivo manipulations of single cells using an all-optical platform
        The hematopoietic stem cell niche is a specialized bone marrow microenvironment where blood-forming cells reside. Interactions between these rare cells and their niche need to be studied at the single-cell level. While live animal cell tracking with optical microscopy has proven useful for this purpose, a more thorough characterization requires novel approaches. This can be accomplished by using an integrated optical platform for cell and tissue manipulations (cell transplantation and extraction) in the skull bone of live mice. The platform integrates a non-damaging laser ablation microbeam for bone removal and tissue cutting, optical tweezers for single cell trapping, and a video-rate multiphoton scanning microscope. For single cell delivery, a narrow channel is ablated through bone under imaging guidance. Cells are then transferred from a micropipette into an optical trap, which brings cells into the bone marrow through the channel. The survival and proliferation of implanted cells can be tracked in vivo by imaging and using standard blood analysis approaches. Critically, our approach uniquely enables the imaging of early stem cell division at the microscopic level, well before extensive proliferation and differentiation have occurred.
        Speaker: Dr Raphael Turcotte (Advanced Microscopy Program, Wellman Center for Photomedicine and Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, MA)
      • 299
        The oligomeric composition of the M2 muscarinic receptor and the G protein signalling complex: a single molecule study
        The role of oligomers in signalling via G protein-coupled receptors (GPCRs) has been under debate. The oligomeric size of several GPCRs has been studied using fluorescence-based techniques and have provided inconsistent results, while their attendant G proteins have received little attention. In this study, the oligomeric nature of the GPCR signalling complex comprising the M2 muscarinic receptor (M2R) and the heterotrimeric G protein Gi1 (Gαi1β1γ2) has been probed using stepwise fluorescence photobleaching. A hexahistidyl-tag and a fluorophore (eGFP) were fused at the N- or C-terminus of M2R, and inserted into Gαi1 (at position 91) or Gγ2 without perturbing the nucleotide-binding affinity of Gαi1 or the interaction with M2R and the Gβ1γ2 heterodimer. Complexes of receptors and G proteins were immobilised on histidine-specific surfaces and their oligomeric size was derived by analyzing the distribution of stepwise changes in fluorescence intensity. Immobilised eGFP-M2R and eGFP- Gαi1β1γ2 both showed four photobleaching steps, which implies a tetramer, and both remain as tetramers when co-expressed and co-purified as the signalling complex. The agonist carbachol, the antagonist N-methylscopolamine (NMS) and the nucleotide guanosine triphosphate (GTP), only affected the oligomeric composition and integrity of either protein when coupled to the other. These findings were corroborated with pair-wise FRET efficiencies measured at the membrane of living cells. Upon activation via M2R, the number of photobleaching steps for Gαi1β1γ2 was reduced to 1-2 after the addition of GTP, suggesting disaggregation into monomers or dimers, and had no effect on M2R. These results were supported with FRET and molecular dynamic simulations, which suggests that G proteins undergo conformational changes upon binding of M2R and GTP. The concerted action of these conformational changes induces movement or alignment of alpha-helical domains which results in the proliferation or disruption of the oligomeric interface between the receptor and the G protein.
        Speaker: Mr Dennis D. Fernandes (Department of Physics, University of Toronto)
      • 300
        Effect of lipid composition on peptide-induced coalescence in bicellar mixtures
        Transfer of lipid material between mulitlamellar reservoirs and the surface active layer is required to maintain the functional surfactant layer in alveoli. Surfactant Protein B (SP-B) is believed to facilitate interlayer contact implicit in such activity. The way in which SP-B might promote trafficking of surfactant material was investigated using mixtures bilayered micelles containing long- and short- chain lipids. Because of their propensity to progressively coalesce into more extended bilayer structures on heating, bicellar mixture suspensions provide interesting systems to study peptide-induced interaction between lipid structures. 2H NMR was used to study the effect of an SP-B fragment (SP-B63-78), at 10% (w/w), on the coalescence behaviour of three bicellar mixtures: DMPC-d54/DMPC/DHPC (3:1:1); DMPC-d54/DMPG/DHPC (3.33:0.67:1); and DMPC-d54/DMPG/DHPC (3:1:1). In bicellar mixtures containing only zwitterionic lipids (DMPC-d54/DMPC/DHPC), the peptide had no effect on the temperatures at which transitions to more extended structures occurred. Conversely, in bicellar mixtures containing anionic lipids (DMPC-d54/DMPG/DHPC), addition of the peptide was found to reduce the temperature at which the magnetically-orientable bicellar ribbon phase was replaced by more extended lamellar structures. This peptide-induced perturbation of bicellar mixture phase behaviour increased with anionic lipid concentration. Comparisons with spectra obtained from DMPC/DMPG-d54/DHPC (3:1:1) and DMPC-d54/DMPG/DHPC (3:1:1) mixtures showed that DMPC and DMPG occupy similar environments in these mixtures both in the presence and absence of the peptide. These results indicate the interaction of SP-B63-78 with lipid structures depends on the presence of anionic lipids and that the mechanism by which SP-B63-78 interacts with bicelles does not involve a separation of anionic and zwitterionic long-chain lipids.
        Speaker: Chris Miranda (Memorial University of Newfoundland)
        Slides
    • W1-3 Special session to honor Dr. Akira Hirose III (DASP-DPP) / Session spéciale en l'honneur du Dr Akira Hirose III (DPAE-DPP) CAB 243

      CAB 243

      University of Alberta

      Convener: Alexandre Koustov (U)
      • 301
        Up, out, and away: Probing the initial stages of ion outflow with Swarm
        Earth's ionized upper atmosphere is ablated into space at a rate of 1 kilogram per second. This outflowing flux is comprised of significant amounts of heavy ions, such as oxygen, whose source populations in the F region ionosphere are sufficiently cool (~1000 K) to be strongly gravitationally bound to the Earth. Here lies a mystery: What processes operate on the cool, dense, low-altitude (*F* region) ionospheric plasma to lift it up, out, and away? The European Space Agency Swarm satellite mission is well-suited to address the low-altitude part, and therefore initial stages, of the outflow problem. In this talk we review several non-classical mechanisms that seemingly conspire to drive low-altitude upflow and, ultimately, atmospheric escape. We survey what is known from past measurements made by satellite and ground-based platforms, including Dynamics Explorer, the Defense Meteorological Satellite Program, and incoherent scatter radars. Finally, we examine what the new, high resolution observations from the Swarm electric field instruments can tell us about the initial stages of ion outflow.
        Speaker: Johnathan Burchill (University of Calgary)
      • 302
        Kinetic modelling of Solar Orbiter space environment
        Solar Orbiter is a European Space Agency (ESA) mission scheduled for launch early in 2017, with the objective of providing observations of unprecedented quality of the sun and solar wind at locations ranging from 0.28 to 0.9 astronomical units (AU). During its journey, Solar Orbiter will experience a vast range of space-environment conditions, including intense radiation and solar wind plasma fluxes near perihelion, and exoisure to high energy particle associated with flares or coronal mass ejections. The interaction of Solar Orbiter with its environment is simulated kinetically for representative solar wind conditions along its orbit, and a particular attention is given to the effect of perturbations associated with plasma-satellite interaction on particle sensor measurements.
        Speaker: Prof. Richard Marchand (University of Alberta)
      • 303
        PLASMA TECHNOLOGY: ITS CURRENT and FUTURE IMPACT ON VARIOUS INDUSTRIES
        Plasma, known also as the forth state of mater, constitutes over 99.9% of our universe. However, our planet appears to be an exception to the rule, where plasma, in its natural state, exists only rarely. The incentive for human to generate and study plasma state started as scientific curiosity, but it has grown into an important enabling industrial tool, with applications in variety of industrial sectors. The proliferation of plasma technology is primarily driven by market forces as well as environmental regulations imposed by various governments, which have opened opportunities for plasma technology to become a substitute technology for applications related to advanced surface engineering and synthesis of new materials, among others. In this presentation we will highlight some of the current and potential future applications of the technology that impact variety of industrial sectors, including renewable energy, health and advanced engineering, by presenting examples that impact (or could impact) the quality of our lives.
        Speaker: Andranik Sarkissian (PLASMIONIQUE Inc)
      • 304
        ZnO Thin Film Samples Produced by Pulsed Laser Deposition for Ultrafast Laser High Harmonics Generation Studies
        The ultrafast laser generated high harmonics is currently a hot research topics. Higher order harmonics generation in a 0.5 mm thick ZnO bulk crystal irradiated by ultrashort pulses from mid IR laser has been reported recently [1]. Because of the long interaction length in the bulk media the effects from self phase modulation become significant and the consequences are deformation of the temporal profile and filamentation. Therefore, in these applications it would be advantageous to use thin film targets. High quality ZnO thin films can be produced using Pulsed Laser Deposition (PLD) [2] and can be optimized for a specific application by varying the deposition parameters. We have carried out a study to produce ZnO thin films with different crystalline characteristics as samples for ultrafast laser generated high harmonics studies. All the ZnO thin films were deposited on sapphire substrates by ablating a ZnO target (99.9 % pure) to produce a ZnO laser plasma with a Krypton Fluoride laser (248 nm, 15 ns) in partial oxygen pressure inside a vacuum chamber. The characterizations of the ZnO laser plasma and thin film samples are carried out using various techniques.
        Speaker: Mr Zachary Tchir (University of Alberta)
    • W1-4 Gravity I (DTP) / Gravité I (DPT) CAB 235

      CAB 235

      University of Alberta

      Convener: Ingrid Stairs (UBC)
      • 305
        Black hole chemistry: thermodynamics with Lambda
        The mass of a black hole has traditionally been identified with its energy. We describe a new perspective on black hole thermodynamics, one that identifies the mass of a black hole with chemical enthalpy, and the cosmological constant as thermodynamic pressure. This leads to an understanding of black holes from the viewpoint of chemistry, in terms of concepts such as Van der Waals fluids, reentrant phase transitions, and triple points. Both charged and rotating black holes exhibit novel chemical-type phase behaviour, hitherto unseen.
        Speaker: David Kubiznak (Perimeter Institute)
        Slides
      • 306
        Restricted Weyl Invariance in Four-Dimensional Curved Spacetime
        We discuss the physics of *restricted Weyl invariance*, a symmetry of dimensionless actions in four dimensional curved space time. When we study a scalar field nonminimally coupled to gravity with Weyl(conformal) weight of $-1$ (i.e. scalar field with the usual two-derivative kinetic term), we find that dimensionless terms are either fully Weyl invariant or are Weyl invariant if the conformal factor $\Omega(x)$ obeys the condition $g^{\mu\nu}\nabla_{\mu}\nabla_{\nu}\Omega=0$. We refer to the latter as *restricted Weyl invariance*. We show that all the dimensionless geometric terms such as $R^2$, $R_{\mu\nu}R^{\mu\nu}$ and $R_{\mu\nu\sigma\tau}R^{\mu\nu\sigma\tau}$ are restricted Weyl invariant. Restricted Weyl transformations possesses nice mathematical properties such as the existence of a composition and an inverse in four dimensional space-time. We exemplify the distinction among rigid Weyl invariance, restricted Weyl invariance and the full Weyl invariance in dimensionless actions constructed out of scalar fields and vector fields with Weyl weight zero.
        Speaker: Prof. Ariel Edery (Bishop's)
        Slides
      • 307
        Revisiting the Solar System and Beyond
        In a recent paper [1] on the modeling of emergent trends in complex biological and physical systems, an overview of the Bayesian approach [2] that we have used to describe the space-time curvature of a static spherically symmetric massive system was presented. The first part of this conference summarizes the main steps of this development. Reinterpreting Einstein gravitation equation in the context of an interdependence principle, we draw attention to an analogy between this equation and the Bayes’ law of conditional probabilities. This leads to proposing a way to incorporate quantum mechanical probabilistic concepts into general relativity to take into account the probability of presence of energy-momentum densities. Focussing on the global field generated by a static spherically symmetric system, under weak field/low speed conditions, we show that a modified Newton’s law of gravitation comes out from such a geometry, as a consequence of an asymptotic convergence predicted by the Central Limit Theorem. The resulting erfc gravitational potential has a mass specific offset which should be directly or indirectly observable in some physical phenomena. In the second part, we focus on such predictions as witnessed by an observer in the solar system. We incorporate the erfc potential into a symmetric metric [3] and briefly explain some salient consequences of this framework. Its impact on flyby maneuvers, Pioneer’s delay and the astronomical unit is first analysed. Some conjectures concerning gravitational collapses, the Hubble constant and the cosmic background temperature are also discussed. [1]Plamondon, R., O’Reilly, C., Ouellet-Plamondon, C., (2014) Strokes against Strokes, Strokes for Strides, Pattern Recognition, 47, 929-944. [2] Plamondon, R.”Patterns in Physics: Toward a Unifying Theory”, Presses Internationales Polytechnique (2012). [3] Plamondon, R., Ouellet-Plamondon, C., (2015) Emergence of a quasi Newtonian law of gravitation: a geometrical impact study, Proc. 13th Marcel Grossman Meeting on General Relativity, K. Rosquist, R.T. Jantzen, R. Ruffini, (Eds), World Scientific, Singapore, 1-3.
        Speaker: Prof. Réjean Plamondon (École Polytechnique de Montréal)
        Slides
      • 308
        Linear perturbations of type IIB SUGRA in flux compactifications
        We consider linear perturbations of the background type IIB SUGRA solutions and find the equations of motion for the moduli. In particular, we allow for spacetime fluctuations of the positions of the D3-branes in the compact dimensions. We postulate an ansatz for the 5-form flux due to the motion of the D3-branes, and a corresponding first-order part of the metric. The movement of the D3-branes is then shown to affect the warp factor at linear order. Using the equations of motion for the D3-branes, the universal volume modulus, and the universal axion, we construct a second-order, effective action. Finally, based on the form of the effect action, we examine a Kahler potential for the moduli space.
        Speaker: Bradley Cownden (University of Manitoba)
      • 309
        Gravitational-wave searches for Binary Black Holes: waveform models
        The direct detection of gravitational waves is imminent with the network of Advanced LIGO, Virgo, Geo, KAGRA detectors coming online. Coalescing binaries of stellar-mass black holes are one of the flagship sources for these terrestrial detectors. Planned detection searches that will be performed over the instrument data rely on models of inspiraling compact binaries. In this talk I would describe how these searches benefit from accurate numerical solutions and analytic models of coalescing compact binaries. I will also present results from recent comparisons of analytic models with high-accuracy numerical simulations of binary black hole mergers, summarizing the accuracy of current waveform models.
        Speaker: Dr Prayush Kumar (Canadian Institute for Theoretical Astrophysics)
    • W1-5 Energy frontier: Future developments (PPD) / Frontière d'énergie: développements futurs (PPD) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Richard Polifka (University of Toronto (CA))
      • 310
        Summary of ATLAS-Canada Upgrades
        Planned upgrades to the LHC will significantly increase its luminosity, leading to large increases in particle flux which will pose a challenge for the ATLAS detector. Phase-1 upgrades, to be installed during the upcoming Long Shutdown 2 during 2018 and 2019, will both enhance the ATLAS trigger system to handle these higher luminosities without damaging physics performance as well as improving muon track reconstruction in the forward region. Phase-2 upgrades, to be in place for the High Luminosity LHC, starting in 2024, will involve further enhancements to the trigger, as well as a full replacement of the Inner Detector and and possibly the forward LAr calorimeter. I will describe the ATLAS upgrade plan with a focus on ATLAS Canada's involvement, in particular on already-in-progress Phase-1 upgrades to the forward muon spectrometer and the LAr calorimeter but also touching on potential involvement in Phase-2 upgrades to the Inner Detector and LAr calorimeter.
        Speaker: William Axel Leight (Carleton University (CA))
        Slides
      • 311
        Test beam performance measurements of novel Thin Gap Detectors for the ATLAS experiment upgrade.
        The planned luminosity increase of the LHC will allow the precise measurement of Higgs boson properties and extend the search for new physics phenomena beyond the standard model. To maintain excellent detection and background rejection capability in the forward region of the ATLAS detector, part of the muon detection system is scheduled to be upgraded during the LHC long shutdown period of 2018-2020. Thin Gap Chambers (TGC) will make up part of this new ATLAS muon small wheel. Results from the testing of a prototype thin gap chamber at the Fermilab and CERN test beam facilities will be presented.
        Speaker: Sebastien Rettie (University of British Columbia (CA))
        Slides
      • 312
        Performance of the first Canadian-made muon chamber prototype for the ATLAS experiment upgrade.
        The planned luminosity increase of the LHC will allow the precise measurement of Higgs boson properties and extend the search for new physics phenomena beyond the standard model. To maintain excellent detection and background rejection capability in the forward region of the ATLAS detector, part of the muon detection system is scheduled to be upgraded during the LHC long shutdown period of 2018-2020. This new ATLAS muon small wheel will partly consists of Thin Gap Chambers (TGC), one third of which will be built and tested in Canada. A description of the chamber production and testing infrastructure in Canada will be presented as well as preliminary results of the performance of the first Canadian-made muon chamber prototype.
        Speaker: Benoit Lefebvre (McGill University (CA))
        Slides
      • 313
        Status of the Future Linear Collider
        The physics potential for an electron-positron linear collider operating at energies above LEP-II has been established for more than a decade. The case is even stronger now that we know the Higgs boson has a mass that allows a linear collider to make precisions studies of its properties. There is renewed excitement in this project with the Japanese Government considering hosting the facility. From the beginning, Canadian physicists have helped establish its physics case and have worked to solve many of its technical challenges. This presentation will summarize the current situation with Japan and the work underway in Canada in detector and accelerator R&D activities in support of a future linear collider.
        Speaker: Prof. Dean Karlen (University of Victoria (CA))
        Slides
    • W1-6 Devices (DCMMP) / Dispositifs (DPMCM) CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Can-Ming Hu (University of Manitoba)
      • 314
        Optical measurement of spin-orbital torque in magnetic bilayers
        Spin-orbital coupling driven toques have been observed in magnetic bilayers consisting of a ferromagnet (FM) and heavy metal (HM) or topological insulator (TI). It has been demonstrated that the spin-orbit torques driven by an in-plane current can switch magnetization, manipulate magnetic domains and excite magnetization auto-oscillation. However, the microscopic mechanism for the spin-orbit torques is still under debate. One of the questions is how to differential the contributions from interface due to the Rashba effect or from bulk of nonmagnetic layer due to the spin Hall effect. In this talk, we will present a newly developed, magneto-optic-Kerr-effect (MOKE) based spin-orbit torque magnetometer that measures both field-like torque (TSOF) and damping-like torque (TSOT) with various thicknesses of the FM, HM TL layers. The technique also offers both spatial and time resolution. We observed both TSOF and TSOT are nonlocal and does not require direct contact between FM and HM. By engineering the interface which modifies the Rashba interaction, we are able to show the co-existence of spin Hall and Rashba effect as well as quantify both contributions to spin-orbit torques.
        Speaker: John Q Xiao (University of Delaware)
      • 315
        Nonlinear Optomechanics for Quantum Nondemolition Measurements
        Since its inception in the early 1900s, the theory of quantum mechanics has provided an excellent model for very small objects, such as single atoms or molecules. However, as we move to larger and larger systems, we eventually return to the classic realm, where Newtonian mechanics takes over. In order to probe this quantum-to-classical crossover, we propose an experiment by which we can measure the quantum nature of a nanomechanical resonator, consisting of billions to trillions of atoms. Using a coupling apparatus on the base plate of a dilution refrigerator, we will cool an optomechanical device such that it is predominantly in its ground state. Then by utilizing a nonlinear coupling mechanism, we will perform an optical quantum nondemolition measurement to probe our mechanical resonator, preventing destructive measurement back-action from perturbing the system. In the context of optomechanics, this arises as an “*x*-squared” measurement, which we have demonstrated for a nanofabricated on-chip device. Under the proper conditions, we expect to be able to directly observe quantized jumps in the phonon number of our system, providing “smoking gun” evidence for quantum mechanics on the mesoscale. In my talk, I will discuss how we will perform such an experiment using our nonlinearly coupled optomechanical system.
        Speaker: Mr Bradley Hauer (University of Alberta)
      • 316
        Optomechanics in a dilution refrigerator
        Recent developments in fabrication techniques have allowed reductions in the size of mechanical resonators to the micro- and nano-scale facilitating their use as exquisite sensors of a variety of phenomena. When coupled to optical cavities, these resonators become an attractive means for investigating the limits of quantum mechanics, as well as powerful tools for building hybrid quantum information processing systems. However, in order to reveal interesting quantum mechanical effects and exploit these systems’ full potential, it is necessary to reduce the thermal occupation of the resonators to very near their ground state. To that end, we have implemented an optomechanical coupling apparatus on the mixing chamber plate of a commercial dilution refrigerator, featuring full three-dimensional control over the resonator coupling conditions as well as a home-built optical microscope which permits *in situ* imaging and alignment of the resonators at temperatures below 10 mK. This talk will outline our design and present preliminary measurements from this cutting edge system.
        Speaker: Allison MacDonald (University of Alberta)
      • 317
        Silicon Nitride microdisk resonators as refractometric sensors in water
        Optical microdisks are intriguing devices due to their small size, compatibility with standard planar micro/nano-fabrication techniques, and ability to support high-Q whispering gallery modes. We fabricate and explore the use of thin (130 nm) Si$_3$N$_4$ disks with diameters of 15 - 30 μm as refractive index sensors, using a dimpled-tapered fiber to couple with the optical modes under water. The thin disks cause evanescent fields to extend far into the surrounding medium, providing large shifts of > 200 nm/refractive index units (RIU) of the optical modes in response to Lithium salts added to the environment. Loaded quality factors of ~$10^4$ let the resonant frequencies to be determined with great accuracy, providing a limit of detection near $10^{-6}$ RIU, comparable with state-of-the-art RI sensors.
        Speaker: Callum Doolin (University of Alberta)
      • 318
        Three-dimensional scanning near field optical microscopy imaging of random arrays of copper nanoparticles and their use for plasmonic solar cell enhancement
        In order to investigate the suitability of random arrays of nanoparticles for plasmonic enhancement in the visible-near infrared range, we introduced three-dimensional scanning near-field optical microscopy (3D-SNOM) imaging as a useful technique to probe the intensity of near-field radiation scattered by random systems of nanoparticles at heights up to several hundred nm from their surface [1]. We demonstrated our technique using random arrays of copper nanoparticles (Cu-NPs) at different particle diameter and concentration. Bright regions in the 3D-SNOM images, corresponding to constructive interference of forward-scattered plasmonic waves, were obtained at heights Δz ≥ 220 nm from the surface for random arrays of Cu-NPs of about 60–100 nm in diameter. These heights are too large to use Cu-NPs in contact of the active layer for light harvesting in thin organic solar cells, which are typically no thicker than 200 nm. Using a 200 nm transparent spacer between the system of Cu-NPs and the solar cell active layer, we demonstrate that forward-scattered light can be conveyed in 200 nm thin film solar cells. This architecture increases the solar cell photoconversion efficiency by a factor of 3. Our 3D-SNOM technique is general enough to be suitable for a large number of other applications in nanoplasmonics. ________ [1] S. Ezugwu, H. Ye and G. Fanchini, Nanoscale 7 (2015) 252-260.
        Speaker: Mr Sabastine Ezugwu (The University of Western Ontario)
    • W1-7 Neutrinoless Double-beta Decay II (PPD-DNP) / Double désintégration beta sans neutrino II (PPD-DPN) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: Gilles Gerbier (Queens University)
      • 319
        The EXO Search for Neutrinoless Double Beta Decay
        The Enriched Xenon Observatory (EXO) effort continues to develop techniques and technology towards the search for neutrinoless double beta decay. Discovery of this process would reveal new properties of neutrinos including first measurement of the neutrino mass scale, evidence that neutrinos are Majorana particles, and first measurement of a lepton number violating process. Searching for the double beta decay process, the collaboration operated a liquid-phase time projection chamber, EXO-200, at WIPP in New Mexico starting in 2010. Data collected with this experiment has led to several physics results and demonstrated the feasibility of the approach. Design and R&D efforts are underway to develop the next-generation double beta decay experiment, nEXO, which will utilize approximately 5 tonnes of xenon enriched in the 136Xe isotope. In this talk, results from EXO-200 will be summarized and the latest update on the developments towards the nEXO experiment will be provided.
        Speaker: Kevin graham
        Slides
      • 320
        Modeling the Leaching of 222Rn Daughters into the SNO+ Detector
        SNO+ is a multi-purpose neutrino experiment which is located at SNOLAB in Sudbury, Ontario. Using 780 tonnes of organic liquid scintillator, SNO+ will search for neutrino-less double beta decay of 130Te. In addition, measuring low energy solar neutrinos are planned for the second phase. Looking for rare events requires very stringent background limits. One of the sources originates from 222Rn daughters implanted into the inner surface of the acrylic vessel (AV). Rn decays to 210Pb which has a relatively long half-life (22 years). Subsequently 210Pb decays by beta emission to 210Bi, and 210Po which are backgrounds for the experiment. Rn daughters can leach into the detector volume, therefore it is important to study the leaching kinetics and its dependence on factors such as temperature, leaching medium and initial conditions. Several bench-top measurements were performed on the leaching rate of 210Pb and 210Po into different mediums. I developed a model based on diffusion physics, which can be used to fit the data and estimate expected background rates from this source for the SNO+ experiment. In January, 2015 an underground water assay was performed on the water which has been contained in the AV for three months. The specific activity in the water was calculated as 0.150(+0.118/-0.058)Bq/m^3 which matches the measured value of 0.26 (+−0.04) Bq/m^3 . This presentation will discuss the leaching model and compare the results with the bench-top measurements.
        Speaker: Pouya Khaghani
        Slides
      • 321
        Using 60Co as a high precision calibration device for the SNO+ detector
        Is the neutrino its own anti-particle? The SNO+ detector at SNOLAB is set to join the international competition of experiments seeking to answer this fundamental question. Its sheer size – a 12 m diameter acrylic sphere holding 780 t of liquid scintillator containing more than 2 t of dissolved tellurium and observed by nearly 9500 photomultiplier tubes – puts SNO+ among those experiments with the best estimated sensitivity to observing the hypothesized rare process of neutrinoless double beta decay. Precisely understanding the signature of this decay in the detector is critical to making any statement regarding whether an operating SNO+ detector has indeed recorded a neutrinoless double beta decay signal. This requires an extensive calibration program. A suite of radioactive calibration sources are designed to investigate properties of the tellurium-loaded liquid scintillator. One such device already constructed contains 60Co, which decays with an output energy very near the total energy released in a 130Te neutrinoless double beta decay, making this calibration source invaluable in understanding this signal region of interest. The source is designed such that all 60Co decays are flagged, enabling the unique identification of calibration events. These events may assist in the study of subtleties of the optical properties of the liquid scintillator.
        Speaker: Logan Sibley (University of Alberta)
        Slides
    • W1-8 Strengthening Physics Departments (DPE) / Renforcer les départements de physique (DEP) CCIS L1-160

      CCIS L1-160

      University of Alberta

      Convener: Donald J. Mathewson (Kwantlen Polytechnic University)
      • 322
        Learning from our neighbours about “Building a Thriving Undergraduate Physics Program” CCIS L1-160

        CCIS L1-160

        University of Alberta

        Many Physics Departments in Canada and around the world face similar challenges: low enrollment numbers for physics majors, long graduation times, retention problems, and the desire – or pressure – to improve the student experience. In February 2015, a team from the Physics Department at SFU attended the “Building a Thriving Undergraduate Physics Program” workshop organized by the APS and AAPT in Seattle. We found these two days so useful and inspiring that we want to share some of what we learned with our Canadian colleagues. In this talk, we will show some highlights from the presentations about departments that reinvented themselves and now thrive, as well as features that strong programs appear to have in common. Next, we will summarize our approach towards building a strategy for our own department. This presentation will be guided by the thoughtful workshop design of Rob Hilborn and Renee Royal and will be shared with their permission. We will conclude by adding data and examples relevant to the situation in Canada.
        Speaker: Daria Ahrensmeier (Simon Fraser University)
      • 323
        Building Thriving Undergraduate Physics Programs
        There are about 760 colleges and universities that offer an undergraduate degree in physics in the United States. Some are small and educate only a few physics students each year, while others attract, educate, and graduate dozens. The American Physical Society and the American Association of Physics Teachers have organized a number of workshops to help departments build and improve their undergraduate programs. This presentation will feature some of the resonate themes from these workshops, and suggest resources and ideas that any faculty member might consider to help them improve their undergraduate program. Specific techniques such as establishing career tracks, developing broader professional skills, emphasizing undergraduate research, and understanding how students approach education will be discussed along with case-studies of departments that re-invented themselves, and built vibrant physics programs in the process.
        Speaker: Dr Theodore Hodapp (American Physical Society)
      • 324
        Panel CCIS L1-160

        CCIS L1-160

        University of Alberta

    • W1-9 Advanced Instrumentation at Major Science Facilities: Detectors II (DIMP) / Instrumentation avancée dans des installations scientifiques majeures: détecteurs II (DPIM) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Kirk Michaelian (Natural Resources Canada)
      • 325
        Advanced Instrumentation Techniques developed for SNOLAB science programmes.
        SNOLAB is a deep underground research facility, based at a depth of 2km in the Vale Creighton mine, near Sudbury, Ontario. The SNOLAB research programme is primarily based around particle and astroparticle physics projects studying the Galactic dark matter, neutrinoless double beta decay and natural sources of neutrinos. Several leading edge technologies have been developed to study these particle interactions, with additional supporting technologies required to ensure the high performance, low energy threshold and low radiogenic background requirements of the experiments. This talk will provide an overview of the particle detection, supporting technologies, and instrumentation techniques developed for the SNOLAB research programme.
        Speaker: Nigel Smith (SNOLab)
        Slides
      • 326
        Ultra-Low Background Counting and Assay Studies At SNOLAB
        Experiments currently searching for dark matter, studying properties of neutrinos or searching for neutrinoless double-beta decay require very low levels of radioactive backgrounds both in their own construction materials and in the surrounding environment. These low background levels are required so that the experiments can achieve the required sensitivities for their searches. SNOLAB has several facilities which are used to directly measure these radioactive backgrounds. This presentation will describe SNOLAB's ultra-low background germanium detectors, describe the data analysis techniques used and present results from these detectors. Descriptions of SNOLAB's alpha-beta and electrostatic counters will be presented and radon levels at SNOLAB will be discussed along with techniques currently being utilised to reduce these levels to limit backgrounds from radon progeny.
        Speaker: Dr Ian Lawson (SNOLAB)
        Slides
      • 327
        Maintaining Clean Rooms at the SNOLAB Underground Laboratory
        The SNOLAB underground laboratory has 50 thousand square feet of floor space all kept as a class 2000 clean room. This suppresses backgrounds from Uranium and Thorium which comprise approximately 1ppm of mine dust and a few ppm of concrete. The systems used to maintain and monitor the cleanliness will be discussed as well as results from cleanliness audits. Air in mines typically has much higher radon content than on surface. At SNOLAB the radon levels are approximately 130 Bq per cubic meter. Systems used to supply small amounts of air from surface will be described with the quality of results achieved.
        Speaker: Chris Jillings (SNOLAB)
        Slides
    • Health Break (with exhibitors) / Pause santé (avec exposants) CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • W-PLEN Plenary Session - Wick Haxton, Univ. of Washington and Univ. of California / Session plénière - Wick Haxton, Univ. de Washington et Univ. de Californie CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Zisis Papandreou (University of Regina)
      • 328
        Neutrino Physics: On Earth and in the Heavens
        The discovery 15 years ago that neutrinos have mass and can spontaneously change their flavors has led to intense activity in nuclear and particle physics, including plans for powerful neutrino beams for long-baseline oscillation experiments and for ton-scale ultraclean underground detectors for double beta decay studies. Our improved knowledge of neutrinos has also enabled us to understand better their roles in astrophysics. Supernova neutrinos may be responsible for important nucleosynthesis in the first stars that formed in our galaxy, and solar neutrinos may allow us to determine the metallicity of the primordial gas cloud from which our solar system formed. I will review some of these themes and their connections, arguing that recent neutrino discoveries are just the beginning of a series of surprises.
        Speaker: Prof. Wick Haxton (University of Washington / University of California)
        Slides
    • W-MEDAL1 CAP Medal Talk - John Page, U. Manitoba (Brockhouse Medal Recipient/Récipiendaire de la médaille Brockhouse) CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Robert Fedosejevs (University of Alberta)
      • 329
        Exploring wave phenomena in complex, strongly scattering materials using ultrasound
        Waves in complex media are often strongly scattered due to mesoscopic heterogeneities, leading to unusual phenomena which continue to fascinate us and enrich our basic understanding of the wave physics of condensed matter. Examples range from strikingly large variations in wave speeds to unusual refraction and tunneling effects, and even to the complete inhibition of wave propagation, due to disorder, that may occur in very strongly scattering samples when waves become localized. Ultrasonic techniques are well suited for investigating such phenomena since complete information about wave propagation (both amplitude and phase, in both time and space) can be measured directly in samples with well controlled internal structures. In this talk I will summarize some of our work on ultrasonic wave transport in both ordered and disordered mesoscopic materials (e.g., phononic crystals, metamaterials and “mesoglasses”), focusing on our recent progress in answering the long–standing question of whether or not Anderson localization of classical waves can really occur in three-dimensional disordered materials. This work is making it possible to study aspects of Anderson localization that have not previously been amenable to experimental investigation, and is contributing to the current resurgence of interest in localization in condensed matter physics and related disciplines.
        Speaker: Dr John Page (University of Manitoba)
    • W-MEDAL2 CAP Medal Talk - Charles Gale, McGill U. (CAP-CRM Prize in Theoretical and Mathematical Physics Recipient / Récipiendaire Prix ACP-CRM en physique théorique et mathématique) CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Richard MacKenzie (U. Montréal)
      • 330
        QCD under extreme conditions: Hot, shiny fluids and sticky business
        The phase diagram of Quantum Chromodynamics (QCD, the theory of the strong interaction) is only poorly known. There is currently a vibrant experimental and theoretical program that concentrate on the study and the characterization of the quark-gluon plasma, a fundamental state of matter that existed a few microseconds after the Big Bang. I will describe the theoretical aspects of this endeavour, and highlight some of the surprises uncovered along the way.
        Speaker: Charles Gale (McGill University)
        Slides
    • DASP Annual Meeting / Assemblée annuelle DPAE CAB 243

      CAB 243

      University of Alberta

      Convener: Prof. Richard Marchand (University of Alberta)
    • DCMMP Annual Meeting / Assemblée annuelle DPMCM CAB 235

      CAB 235

      University of Alberta

      Convener: Mona Berciu (University of British Columbia)
    • DIMP-DIAP Annual Meeting / Assemblée annuelle DPIM-DPIA CCIS L1-029

      CCIS L1-029

      University of Alberta

      Conveners: Kirk Michaelian (Natural Resources Canada), René Roy (Université Laval)
    • DPE Annual Meetings / Assemblée annuelle DEP CCIS L1-160

      CCIS L1-160

      University of Alberta

      Convener: Calvin Kalman (Concordia University)
    • Lunch / Dîner
    • W2-1 Spintronics and spintronic devices (DCMMP) / Spintronique et technologies spintroniques (DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Can-Ming Hu (University of Manitoba)
      • 331
        Spin Currents in Magnetic Insulator/Normal Metal Heterostructures
        The generation and the detection of pure spin currents are fascinating challenges in modern solid state physics. In ferromagnet/normal metal thin film heterostructures, pure spin currents can be generated, e.g., by means of spin pumping [1], or via the application of thermal gradients in the so-called spin Seebeck effect [2]. An elegant scheme for detecting spin currents relies on the inverse spin Hall effect: Owing to spin-orbit coupling, a spin current flowing in a normal metal also induces a charge current, which can be straightforwardly detected using conventional electronics [1,2]. In the talk, I will discuss some of our recent spin current-related experiments in magnetic insulator/normal metal heterostructures [3-5]. Magnetic insulators are very attractive materials for spin current experiments, since they do exhibit long-range magnetic order and thus can sustain pure (magnonic) spin current flow, while they do not conduct electrical charge. We take advantage of this fact and study the spin Seebeck effect in both yttrium iron garnet (Y3Fe5O12, YIG) as well as gadolinium iron garnet (Gd3Fe5O12, GdIG) based heterostructures [5]. While the spin Seebeck voltage in YIG/Pt heterostructures “simply” goes to zero upon decreasing temperature, it changes sing twice in GdIG/Pt. The spin currents thus do not simply replicate the net magnetization of the ferrimagnetic insulator, but rather reflect the complex interplay between the different magnetic sublattices. Furthermore, I will introduce and discuss the so-called spin Hall magnetoresistance effect in these heterostructures [3,4]. References: [1] O. Mosendz et al., Phys. Rev. Lett. 104, 046601 (2010). [2] K. Uchida et al., Nature Mater. 9, 894 (2010). [3] H. Nakayama et al., Phys. Rev. Lett. 110, 206601 (2013). [4] M. Weiler et al., Phys. Rev. Lett. 111, 176601 (2013). [5] S. Geprägs et al., arXiv 1405:4971
        Speaker: Dr Sebastian Goennenwein (Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching, Germany)
        Slides
      • 332
        Controlling magnetization dynamics with artificial pinning sites in thin magnetic disks
        Spatial inhomogeneity on the nanoscale is intrinsic to most thin film materials used in nanomagnetic technology, and can affect both static and dynamic magnetic responses [1]. Understanding the detailed effects of local inhomogeneity becomes increasingly important as device dimensions shrink. Focused ion beam irradiation is an elegant way to carry out local magnetic patterning to create highly confined magnetic pinning sites. The strength and lateral dimension of the sites are tailored by varying the beam dose. A quantitative understanding of magnetic pinning has been gained through studies of the quasi-static (Barkhausen) response of a magnetic vortex core interacting with the local energetic landscape [2,3]. The corresponding modification of dynamics arising from the presence of engineered pinning sites will be discussed. Experimental measurements using an extension of nanomechanical torque magnetometry [4], are complemented by numerical micromagnetic simulations. Refs: 1- R. L. Compton et al., PRL 97, 137202 (2006). 2- F. Fani Sani , et al., J. Appl. Phys. 115 , 17D131 (2014). 3- J.A.J. Burgess et al., Science 339 , 1051 (2013). 4- J.E. Losby, et al., Solid State Commun. (2014)
        Speaker: Fatemeh Fani Sani (UofA)
      • 333
        Spin pumping in electrodynamically coupled magnon-photon systems
        Lihui Bai$^{1}$, M. Harder$^{1}$, Y. P. Chen$^{2}$, X. Fan$^{2}$, J. Q. Xiao$^{2}$, and C.-M. Hu$^{1}$ $^{1}$Department of Physics and Astronomy, University of Manitoba, Winnipeg, Canada R3T2N2 and $^{2}$Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA We use electrical detection, in combination with microwave transmission, to investigate both resonant and non-resonant magnon-photon coupling at room temperature. Spin pumping in a dynamically coupled magnon-photon system is found to be distinctly different from previous experiments. Characteristic coupling features such as modes anti-crossing, line width evolution, peculiar line shape, and resonance broadening are systematically measured and consistently analyzed by a theoretical model set on the foundation of classical electrodynamic coupling. Our experimental and theoretical approach pave the way for pursuing microwave coherent manipulation of pure spin current via the combination of spin pumping and magnon-photon coupling.
        Speaker: Dr Lihui Bai (University of Manitoba)
      • 334
        Towards Microwave-Frequency Spin Mechanics
        Torque magnetometry using torsional resonators provides a highly sensitive platform for resolving magnetic signatures in single meso-scale elements. In the static case, sample magnetizations are biased using a DC field while an AC excitation is applied at a frequency equal to the mechanical resonance of the torsional device. The resulting torque is then measured using an interferometric technique. One challenge in probing dynamics is that the interferometric signal must be demodulated at this fixed mechanical resonance; however, early studies in spin mechanics have met this challenge and produced a technique for simultaneously acquiring static and dynamic magnetization in the audio-frequency regime [1]. This approach has since been extended by orders of magnitude (up to several hundred megahertz), where spin resonances and other dynamic phenomena have been observed [2]. Pushing this frequency limit further still requires innovative new demodulation techniques. Here we discuss current methodologies to probe a single yttrium iron garnet microdisk for pinned resonant modes, higher order spin waves, and the Einstein-de Haas effect up to frequencies of a few gigahertz. [1] J. E. Losby *et al*., Solid State Communications, **198** (2014), 3-6. [2] J. E. Losby *et al*., Manuscript in prep.
        Speaker: Dylan Grandmont (Department of Physics, University of Alberta, Edmonton, Alberta, Canada T6G 2G7)
      • 335
        Explosive molecule detection by nanomechanical resonator and photothermal spectroscopy
        Nanomechanical resonators are good sensors because of their small mass, high frequency and high quality factor. In particular for mass sensing, the adsorbent mass is estimated from the shift in mechanical resonance frequency. Fantastic progress has been made in mass sensitivity, reaching the single protein and even yoctogram mass level. Yet this technique alone is not sufficient to identify the adsorbent molecule. We must add a second technique to our system to gain chemical specificity. Photothermal infrared (IR) spectroscopy, a technique based on IR absorption by resonant molecular vibrations, is straight forward, simple, and easy to couple to the system. The molecule absorbs light at the wavelength of its molecular vibration, producing heat, resulting in a shift of the resonance frequency of the resonator. Combining this IR absorption spectroscopy with nanostring mechanical resonators, we have detected femtogram levels of the explosive molecule 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), representing the lowest RDX values ever measured by IR spectroscopy.
        Speaker: Tushar Biswas (Department of Physics, University of Alberta)
    • W2-10 Spectroscopy and Optics (DAMOPC) / Spectroscopie et optique (DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Paul Haljan (Simon Fraser University)
      • 336
        SPIN-ROTATION HYPERFINE SPLITTINGS AT MODERATE TO HIGH J VALUES IN METHANOL
        In this talk we present a possible explanation, based on torsionally mediated proton-spin-overall-rotation interaction operators, for the surprising observation in Nizhny Novgorod several years ago[1] of doublets in some Lamb-dip sub-millimeter-wave transitions between torsion-rotation states of E symmetry in methanol. These observed doublet splittings, some as large as 70 kHz, were later confirmed by independent Lamb-dip measurements in Kharkov. In this talk we first show the observed J-dependence of the doublet splittings for two b-type Q branches (one from each laboratory), and then focus on our theoretical explanation. The latter involves three topics: (i) group theoretically allowed terms in the spin-rotation Hamiltonian, (ii) matrix elements of these terms between the degenerate components of torsion-rotation E states, calculated using wavefunctions from an earlier global fit of torsion-rotation transitions of methanol in the vt = 0, 1, and 2 states[2], and (iii) least-squares fits of coefficients of these terms to about 35 experimentally resolved doublet splittings in the quantum number ranges of K = -2 to +2, J = 13 to 34, and vt = 0. Rather pleasing residuals are obtained for these doublet splittings, and a number of narrow transitions, in which no doublet splitting could be detected, are also in agreement with predictions from the theory. Some remaining disagreements between experiment and the present theoretical explanation will be mentioned. [1] G. Yu. Golubiatnikov, S. P. Belov, A. V. Lapinov, "CH3OH Sub-Doppler Spectroscopy," (Paper MF04) and S.P. Belov, A.V. Burenin, G.Yu. Golubiatnikov, A.V. Lapinov, "What is the Nature of the Doublets in the E-Methanol Lamb-dip Spectra?" (Paper FB07), 68th International Symposium on Molecular Spectroscopy, Columbus, Ohio, June 2013. [2] Li-Hong Xu, J. Fisher, R.M. Lees, H.Y. Shi, J.T. Hougen, J.C. Pearson, B.J. Drouin, G.A. Blake, R. Braakman, "Torsion-Rotation Global Analysis of the First Three Torsional States (vt = 0, 1, 2) and Terahertz Database for Methanol," J. Mol. Spectrosc., vol.251, 305-313, (2008).
        Speaker: Li-Hong Xu (University of New Brunswick)
      • 337
        Atomic Recoil Processes following He-6 Beta Decay
        There are currently several experiments in progress to search for new physics beyond the Standard Model by high precision studies of angular correlations in the $\beta$ decay of the helium isotope $^6{\rm He} \rightarrow\, ^6{\rm Li} + e^- + \bar{\nu}_e$. An essential part of the analysis is to understand the energy distribution and spectra of the recoil ions. After the $\beta$ decay event, the atomic electrons suddenly find themselves in a $^6$Li$^+$ environment with nuclear charge $Z = 3$. The electrons redistribute themselves over all possible states of the $^6$Li$^+$ ion, including the continuum leading to $^6$Li$^{++}$ and $^6$Li$^{3+}$. Evidence for new physics beyond the Standard Model would reveal itself by an additional tensor coupling contribution to the weak interaction, in addition to the simple Gamow-Teller axial-vector mechanism. We will present calculations employing Stieltjes imaging techniques in Hylleraas coordinates to study the probabilities for the shake-up and shake-off mechanisms, and especially the additional recoil accompanying the emission of the shake-off electrons. The results are of key importance in the interpretation of angular correlations following $\beta$ decay.
        Speaker: Dr Gordon Drake (University of Windsor)
      • 338
        The spectrum of 15NH3 in the 66-2000 cm-1 region
        Ammonia is indeed an ubiquitous molecule, it can be found in various astrophysical objects such as planetary atmospheres, comets and interstellar medium, and its presence in exoplanets and in the atmosphere of cold stars must be taken in serious consideration. The 15N isotopic variety could be very important since it allows the knowledge of the 14N/15N ratio in the universe. Although lists of precise molecular transitions obtained from ab-initio calculations at various temperature up to 1500 K are available in the literature for both 14NH3 and 15NH3 the very accurate and precise measurements obtained in this work may support the spectroscopic observations of SOFIA, Herschel and of the ground based ALMA. Here we report on the observation and the analysis of all vibrational transitions falling below 2000 cm-1, namely n2 ← GS, n4 ← GS and 2n2 ← GS and the hot bands 2n2 ← n2, n4 ← n2 and 2n2 ← n4. Transitions up to J = 15, have been identified and fitted, together with the rotation-inversion transition in all the excited states, using of a computer program based on an effective Hamiltonian which takes into account all symmetry allowed interactions between and within the excited states. About 6300 transitions have been observed, 5700 of these have been so far retained in the fit.
        Speakers: Li-Hong Xu (University of New Brunswick), Ronald Lees (University of New Brunswick)
        Paper
        Slides
      • 339
        Generalized Waveguide Theory including Electromagnetic Duality
        We introduce a general theory for describing modes and characteristics of linear, homogeneous, isotropic waveguide materials and metamaterials with slab and cylindrical geometries. Our theory accommodates exotic media such as double-negative-index and near-zero-index metamaterials as special cases, and we demonstrate that our general theory exhibits electromagnetic duality that would arise if we were to incorporate magnetic monopoles into the media. To ensure manifest electromagnetic duality, we construct generic electromagnetic susceptibilities for the constituent materials using a generalized Lorentz-Drude model that manifests this duality, and our model reduces to standard cases in appropriate limits. Using our theory, we present and explain intriguing modes arising in waveguides that exploit such exotic materials and metamaterials. In particular, we show that, in slab and cylindrical hollow-core metamaterial waveguides, exchanging electric and magnetic material properties leads to the exchange of transverse magnetic and transverse electric modes, which suggests a good test of the potential duality of waveguides. We appreciate financial support from the NSERC and AITF.
        Speaker: Mrs Nafiseh Sang-Nourpour (Institute for Quantum Science and Technology, University of Calgary, Alberta T2N 1N4, Canada ; Photonics Group, Research Institute for Applied Physics and Astronomy, University of Tabriz, Tabriz 51665-163, Iran)
      • 340
        **WITHDRAWN** Observing the effects of Time Ordering in Single Photon Frequency Conversion
        Frequency conversion (FC) is one of the most common nonlinear processes used in quantum optics. This process has the property that the Hamiltonian that governs it does not commute with itself at different times, and hence time ordering becomes an important aspect in the description of its dynamics. Recently, it has been shown that the Magnus expansion provides an appropriate description of the effects of time ordering in several nonlinear quantum optical processes[1-2]. One of the most important results derived from the use of the Magnus expansion in nonlinear optics is that the joint conversion amplitude (JCA) that governs the conversion processes in FC becomes a nonlinear function of the classical pump electric field because of time ordering effects. In the low pump intensity regime, and assuming that the joint conversion amplitude can only upconvert one Schmidt frequency mode, one can show that the probability of upconversion is $\sin ^2\varepsilon$ where $\varepsilon$ is linearly related to the peak electric field of the pump. As the intensity is increased time ordering corrections create more Schmidt frequency modes, with a dependence on the electric field of the pump is nonlinear. With these observations in mind, we predict that efficiencies of maximum $80\%$ can be achieved by using intensities that make $\sin^2 \varepsilon \approx 1$. The inability to achieve $100\%$ conversion is due to two effects: 1. None of the Schmidt functions of the full JCA, including time ordering, will perfectly match the profile of the initial photon that is matched to the low pump intensity JCA. 2. The parameter $\varepsilon$ that determines the ``rotation angle'' of the single photon is, because of ordering effects, a nonlinear function of the electric field. We also find that these nonlinearities can also help achieve unit efficiencies by harnessing more than one of Schmidt mode of the high pump intensity JCA. With this observations in mind we propose an experiment where these nonlinear effects can be observed and used to achieve near unit efficiency FC. [1] N. Quesada and J.E. Sipe, Phys. Rev. A **90**, 063840 (2014). [2] N. Quesada and J.E. Sipe, to appear in Phys. Rev. Lett. (2015) (arXiv:1410.0012 ).
        Speaker: Nicolas Quesada (University of Toronto)
      • 341
        Accurate and Precise Characterization of Linear Optical Interferometers
        We combine single- and two-photon interference procedures for characterizing any multichannel passive linear optical interferometer accurately and precisely. Accuracy is achieved by accounting for systematic errors due to spatiotemporal and polarization mode mismatch and estimating those mismatch parameters through calibrating on one known beam splitter. Enhanced precision is achieved by curve fitting to measured quantities based on a Poissonian shot noise assumption, and we employ bootstrapping statistics to quantify the resultant degree of precision. We demonstrate the efficacy of our procedure via testing with simulations and then experimentally.
        Speaker: Mr Ish Dhand (University of Calgary)
        Slides
    • W2-11 Microfluidics and Driven Motion (DMBP) / Microfluidique et mouvement forcé (DPMB) CAB 235

      CAB 235

      University of Alberta

      Convener: Maikel Rheinstadter (McMaster University)
      • 342
        Measuring flow and yielding with coherent x-rays
        When coherent radiation is scattered by particles, its scattering pattern is modulated by *speckle*. If the scattering particles move, the speckle will change accordingly. This principle forms the basis of XPCS (X-ray photon correlation spectroscopy), which utilizes bright, coherent X-rays to probe nanoscale particle motion. We will discuss our recent efforts to extend XPCS in two different directions: the measurement of fluid flow, and the yielding of colloidal gels. The flow technique involves measuring scattering particle motion in pressure-driven microchannel flow. Our yielding experiments involve in situ measurements of nanocolloidal gels subjected to oscillatory shear strain, which provides information about the spatial character of particle rearrangements during yielding at the nanometer scale.
        Speaker: Michael Rogers (University of Ottawa)
      • 343
        Structure Determination from Single-Particle X-ray Imaging
        X-ray free electron lasers, such as Linac Coherent Light Source at SLAC, can be used to generate diffraction patterns of non-crystalline biological objects, like viruses. Then the main goal is to extract the high-resolution 3D structure of such particles by assembling 2D diffraction data with random orientations. However, structure determination still remains as a major challenge, and powerful algorithms are in high demand. We present a new approach for reconstructing the 3D anatomy of symmetric objects such as viruses, using simulated random diffraction snapshots generated by X-ray free electron lasers. We show that a manifold embedding technique is able to determine the orientations of diffraction patterns of a small virus with sufficient accuracy for atomic-level reconstruction of its structure. We also discuss challenges and possibilities in structural recovery of macromolecules from the experimental X-ray data.
        Speaker: Dr Ahmad Hosseinizadeh (Univ. of Wisconsin, USA)
      • 344
        Investigating the correlation between molecular structure and mechanical properties of collagen using optical tweezers
        Collagens represent a prominent family of fibrous structural proteins present in the majority of connective tissues in mammals that contribute to their mechanical behaviors. Collagen self-assembles into well-defined structures including fibrils, which makes it an excellent example of a hierarchical biological system with a broad range of functions. It is known that fibril formation kinetics can be slowed down considerably by removal of short regions at both ends of collagen molecules called telopeptides. It has been suggested that telopeptides act by forming specific, transient interactions with other collagens, which could facilitate faster fibril formation. In this study, to identify and characterize interactions between collagen molecules, local viscoelastic properties of collagen systems are probed using optical tweezers.
        Speaker: Dr Marjan Shayegan (Postdoctoral Researcher)
      • 345
        Interferometric second harmonic generation imaging of biological tissues
        In recent years, Second Harmonic Generation (SHG) microscopy has emerged as a powerful technique to image in situ non-centrosymmetric structures in biological tissues, such as collagen, a major structural protein of vertebrates. However, due to the coherence of SHG signal, intensity depends not only on the density and the overall organization of harmonophores, but also on their relative polarity within the focal volume. In SHG imaging, the phase of the signal, which contains this additional structural information, is lost in the measurements which has impeded up to now the study of the nanoscale arrangement of the fibrils' polarity. To overcome this limitation we recently, proposed Interferometric SHG (I-SHG) microscopy. In I-SHG microscopy, second harmonic is generated twice: first outside the microscope, to provide a reference SHG beam, and second within the sample, to probe the fibrils’ polarity. By varying the phase between the two beams that are interfering, the relative phase of the second-order susceptibility, or equivalently the relative orientation of the second harmonic emitters, can be retrieved pixel by pixel. As a proof of concept we first applied I-SHG to the study of myosin filaments in muscles and highly organized collagen bundles in tendons. However, the investigation of tissues exhibiting more complex collagen architecture, such as cartilage, has been hindered so far by the low interferometric contrast obtained with picosecond pulses laser. We therefore implemented for the first time I-SHG using femtosecond pulses and applied it to study the collagen meshwork in cartilage. To do so, we developed a collinear setup to compensate for the dispersion introduced in the microscope as to optimize both spatial and temporal overlap. The results are analyzed in regards of numerical simulations showing that the phase measurements can be related to the local ratio of fibrils with opposite polarities, which is responsible for the strong variations of signal intensity in our images. A comparison with standard and polarization-resolved SHG highlights the role of both tissue organization and relative fibril polarity in determining the SHG signal intensity. This work illustrates how the complex architecture of non-centrosymmetric scatterers at the nanoscale governs the coherent building of SHG within the focal volume and the observed features in SHG images.
        Speaker: Prof. François Légaré (INRS-EMT)
      • 346
        MR Imaging with Radiofrequency Phase Gradients
        Although MRI offers highly diagnostic medical imagery, patient access to this modality worldwide is very limited when compared with X-ray or ultrasound. One reason for this is the expense and complexity of the equipment used to generate the switched magnetic fields necessary for MRI encoding. These field gradients are also responsible for intense acoustic noise and have the potential to induce nerve stimulation. We present results with a new MRI encoding principle which operates entirely without the use of conventional B0 field gradients. This new approach – ‘Transmit Array Spatial Encoding’ (TRASE) – uses only the resonant radiofrequency (RF) field to produce Fourier spatial encoding equivalent to conventional MRI. High-resolution two-dimensional-encoded in vivo MR images of hand and wrist have been obtained at 0.2 T. TRASE exploits RF field phase gradients, and offers the possibility of very low-cost diagnostics and novel experiments exploiting unique capabilities, such as imaging without disturbance of the main B0 magnetic field.
        Speaker: Dr Jonathan Sharp (University of Alberta)
    • W2-2 Quantum Information and Quantum Computation (DTP-DCMMP) / Information et calcul quantique (DPT-DPMCM) CAB 239

      CAB 239

      University of Alberta

      Convener: Svetlana Barkanova (Acadia University)
      • 347
        Wigner function negativity and contextuality in quantum computation on rebits
        We describe a universal scheme of quantum computation by state injection on rebits (states with real density matrices). For this scheme, we establish contextuality and Wigner function negativity as computational resources, extending results of [M. Howard et al., Nature 510, 351–355 (2014)] to two-level systems. For this purpose, we define a Wigner function suited to systems of n rebits, and prove a corresponding discrete Hudson’s theorem. We introduce contextuality witnesses for rebit states, and discuss the compatibility of our result with state-independent contextuality.
        Speaker: Robert Raussendorf (UBC)
      • 348
        Orbital Interference Effects in Nanowire Josephson Junctions for Exploring Majorana Physics
        The Josephson effect in a nanowire-based superconductor-normal-superconductor (SNS) junction is studied theoretically and experimentally, focusing on the effects of nanoscale confinement on the current-phase relationship of the junction. We identify a new type of Josephson interference based on the coupling of an applied axial magnetic flux to N-section Andreev quasiparticles (bound and continuum states) occupying electronic subtends of non-zero orbital angular momentum. The Bogoliubov-de Gennes equations are solved while considering the transverse subbands in the N-section, yielding energy-versus-phase curves that are shifted in phase in the presence of the flux. A similar phase shift is observed in the continuum current of the junction. Experimental observations of similar oscillations of critical current in a Nb-InAs nanowire-Nb junction are described, and analyzed in the context of our theoretical model. Since this type of semiconductor-superconductor junction can, in theory, support Majorana fermions, this orbital interference effect must be taken into account when looking for topological signatures in the critical current versus field and temperature.
        Speaker: Jonathan Baugh (University of Waterloo)
      • 349
        Multiqubit entangled channels for quantum communication in networks
        Multiqubit entangled states are an important resource for networked information processing and communication. Here, we explore the use of entangled channels for various controlled teleportation schemes. In controlled teleportation (CT), the teleportation can proceed only with the permission and participation of one or more controllers. Thus, the controller’s role is of key importance in CT protocols. We present a quantifiable measure of the controller’s power in N-qubit controlled teleportation. We apply our measure to evaluate the control power in several existing CT schemes. We also discuss the general rules that must be satisfied by controlled teleportation schemes to ensure both teleportation fidelity and control power. Our measure of control power is simple, practical and applicable to evaluate all CT schemes for teleporting N-qubit pure states. Practically feasible schemes for preparing multiqubit entangled states are required in order to implement large-scale quantum communication protocols. Our results provide guidelines for developing robust teleportation schemes using both maximally entangled states as well as partially entangled channels.
        Speaker: Shohini Ghose (Wilfrid Laurier University)
    • W2-3 Gravity II (DTP) / Gravité II (DPT) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: Ariel Edery (Bishop's University)
      • 350
        Gravitational Waves Probes of Extreme Gravity Physics
        Einstein's theory has passed all tests to date in the quasi-stationary weak-field, where gravitational dynamics are weak and quadrupolar, while velocities are small relative to the speed of light. The highly non-linear and dynamical regime of the gravitational interaction, however, remains mostly unexplored. The imminent detection of gravitational waves will open a window into this regime that will allow us to confront Einstein's predictions with extreme gravity data to unprecedented levels. In this talk, I will review what physics and General Relativistic principles will be put to the test in the extreme gravity regime with gravitational waves.
        Speaker: Prof. Nicolas Yunes (Montana State University)
      • 351
        Searching for Nanohertz Gravitational Waves Using Pulsars
        Millisecond radio pulsars (MSPs) exhibit tremendous rotational stability and therefore provide a means to detect gravitational waves passing near the Earth. Three collaborations are using the world's largest radio telescopes to observe arrays of MSPs with the goal of making such a detection. This talk will review the expected gravitational-wave sources, the methodology and the future prospects of this experiment.
        Speaker: Ingrid Stairs (UBC)
      • 352
        Searching for gravitational waves from compact binary coalescences with Advanced LIGO
        Gravitational waves are distortions in the metric of space-time, the detection of which would provide key information on strong gravity and the astrophysical systems that produce them: supernovae, spinning compact stars, and the coalescence of compact binary systems (CBCs). LIGO is a gravitational wave observatory composed to two 4km interferometric detectors separated by 3000km, in Hanford WA and Livingston LA. These second-generation interferometers were recently installed, light resonated in coupled cavities, and noise-reduction and stabilization experiments made to ready them for observations. In September 2015, we anticipate the first of a series of multi-month observation runs at increasing sensitivity, in which we expect to first detect gravitational waves, and then begin a phase of regular observations. One promising candidate for first detection is that of compact binary coalescences, or CBCs. In this talk, we will review both i) the status of the instrument, and ii) the methods and prospects for detection of compact binaries such as pairs of neutrons stars, pairs of black holes, or one of each.
        Speaker: Michael Landry (LIGO Hanford Observatory/Caltech)
        Slides
    • W2-4 Testing Fundamental Symmetries I (DNP-PPD) / Tests de symétries fondamentales I (DPN-PPD) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Jenna Smith (TRIUMF)
      • 353
        Casting Light on Antimatter: Fundamental Physics with the ALPHA Antihydrogen Trap
        ALPHA is an international project at CERN, with substantial Canadian involvement, whose ultimate goal is to test symmetry between matter and antimatter via comparisons of the properties of atomic hydrogen with its antimatter counter-part, antihydrogen. After several years of development, we have recently achieved significant milestones, including the first stable confinement of antihydrogen [1] for as long as 1000 seconds [2]. ALPHA has also succeeded in performing the first proof-of-principle spectroscopic measurement on antihydrogen atoms by driving their hyperfine transitions with microwaves [3]. Furthermore, we reported a precision measurement of charge neutrality of antihydrogen [4], which in turn provides an improved measurement of the electric charge of the positron. Following these milestones, we have constructed an entirely new apparatus, ALPHA-2, which allows laser access to the trapped anti-atoms, and provides improved magnetic field configurations for microwave spectroscopy. For the longer-term, possibilities for measurements of the antimatter-gravity interaction are being explored. This talk will discuss the motivations, recent achievements and the future prospects of fundamental physics studies with ALPHA. References : [1] G. B. Andresen et al., Nature 468, 673 (2010). [2] G.B. Andresen et al., Nature Physics 7, 558 (2011). [3] C. Amole et al., Nature 483, 439 (2012). [4] C. Amole et al. Nature Communications 5, 3955 (2014)
        Speaker: Dr Makoto Fujiwara (TRIUMF)
      • 354
        High Precision Weak Charge Measurements using Parity Violating Electron Scattering: Looking for Signatures of New Physics at the Precision Frontier
        Measurements of the parity violating electron-proton and electron-electron asymmetries in the number of scattered electrons can be extremely sensitive probes for signatures of new physics beyond the standard model up to mass scales as high as $\Lambda/g \simeq 7.5~ TeV$. The basic reason for this is that the measured asymmetry has a simple and, within the Standard Model (SM), precisely calculated relation to the weak charges of the proton and the electron (more so in the latter case) and that the weak charges are fundamental and suppressed/small parameters of the SM. To do this, however, a number of significant experimental challenges have to be overcome. Specifically, the small, part per billion level, asymmetries require very high statistics to achieve the necessary precision and very tight control of systematic effects to achieve the desired accuracy. I will discuss two experiments that fall into this category: I will provide a brief update on the status of the QWeak experiment (electron-proton), which is currently in the final analysis stages, and I will provide an update on the development status of the planned MOLLER experiment (electron-electron). I will provide an overview of the new physics sensitivities and complementarity of the two measurements.
        Speaker: Michael Gericke (University of Manitoba)
      • 355
        Muon g-2/edm at J-PARC
        The anomalous magnetic moment of the muon, a_mu = (g_mu - 2)/2, has been measured to 0.54 ppm, and when compared to the Standard Model (SM) calculation of similar precision, a discrepancy of 3.6 sigma remains unexplained. This is perhaps a hint of new interactions beyond the SM, stimulating much theoretical interest and speculation. The muon g-2 experiment responsible for this measurement, Brookhaven E821, is to be repeated by Fermilab E989 using the same 14 m diameter storage ring with the goal of a fourfold reduction of uncertainty. Meanwhile, an alternative method has been proposed and developed to become the J-PARC muon g-2/edm experiment, E34. While the J-PARC goal is similar, the storage ring is a mere 0.66 m in diameter and the techniques are largely new in order to avoid where possible any systematic biases common to 821 and 989. The J-PARC g-2/edm experiment presents many challenges, and some significant progress in meeting them will be described in this talk. * on behalf of the J-PARC muon g-2/edm (E34) collaboration
        Speaker: Glen Marshall (TRIUMF)
        Slides
      • 356
        Investigation of the E2 and E3 matrix elements in $^{200}$Hg using direct nuclear reactions
        A nuclear-structure campaign has been initiated to investigate the isotopes of Hg around mass 199. To date, $^{199}$Hg provides the most stringent limit on an atomic electric dipole moment (EDM)$~$[1]. The observation of a permanent EDM would represent a clear signal of CP violation from new physics beyond the Standard Model. Theoretical nuclear-structure calculations for $^{199}$Hg are challenging, and give varied predictions for the excited-state spectrum. Understanding the E2 and E3 strengths in $^{199}$Hg will make it possible to develop a nuclear structure model for the Schiff strength based on these matrix elements, and thereby constrain present models that predict the contribution of octupole collectivity to the Schiff moment of the nucleus. One of the most direct ways of measuring the matrix elements connecting the ground state to excited states is through inelastic hadron scattering. The high level density of a heavy odd-A nucleus like $^{199}$Hg makes a measurement extremely challenging. Complementary information can, however, be determined for states in the neighbouring even-even isotopes of $^{198}$Hg and $^{200}$Hg, and single-nucleon transfer reactions on targets of even-even isotopes of Hg can yield important information on the single-particle nature of $^{199}$Hg. The work presented here comprises two experiments which use a 22 MeV deuteron beam incident on an isotopically enriched target of $^{200}$Hg$^{32}$S. The first experiment was an inelastic deuteron scattering experiment, $^{200}$Hg(d,d')$^{200}$Hg, and included 20 angles ranging from 10$^{\circ}$ to 115$^{\circ}$ up to an excitation energy of $\sim 6~\textrm{MeV}$. The second experiment was a single-nucleon transfer reaction into $^{199}$Hg, $^{200}$Hg(d,t)$^{199}$Hg, and included 10 angles from 5$^{\circ}$ to 50$^{\circ}$ up to an excitation energy of $\sim 3~\textrm{MeV}$. These experiments were performed using the Q3D magnetic spectrograph at the Maier-Leibnitz Laboratory. Results from these experiments will be presented. [1] W. C. Griffith et al., Phys. Rev. Lett. 102, 101601 (2009).
        Speaker: Evan Rand (University of Guelph)
    • W2-5 Atmospheric physics (DASP) / Physique atmosphérique (DPAE) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Prof. Thayyil Jayachandran (University of New Brunswick)
      • 357
        Measurement of Mesospheric Ozone Using Meteor Decay Times
        Mesospheric Ozone has significant chemical impact in the upper atmosphere, and its seasonal and annual variability needs to be better understood. Many large and expensive satellites have been flown over the last 20 years in search of such measurements. By carefully investigating the role of ozone in the high-temperature, hypersonic environment of overdense meteors, we have been able to develop a procedure by which the complementary cumulative histogram of overdense meteor decay times can be used to determine the absolute ozone density in the height region from 80 to 95 km with time resolutions of a few days, and height resolution of about 2-3 km. We present the basic theory behind the technique, and show temporally coincident comparisons with previous satellite data, demonstrating good agreement. Given that there are over 40 existing radars world-wide that can use this technique, the method has the potential to produce global-scale maps of the ozone density on a continuous basis.
        Speaker: Prof. Wayne Hocking (University of Western Ontario)
      • 358
        Wind and Gravity Wave Observations with ERWIN-II
        The ERWIN-II (improved E-Region Wind Interferometer) is a Michelson interferometer, located at the Polar Environment Atmospheric Research Laboratory (PEARL) in Eureka, Nu. It measures the airglow irradiance and winds via Doppler shifts in the airglow emissions – green line (557.7 nm) at a height of ~97 km, O2 (560 nm) at ~94 km, and OH (543 nm) at ~87 km. These measurements are made at a very high cadence (~3 minutes) and precision (~1 m/s for green line and OH, and ~4 m/s for O¬); this allows for measurements of both the larger scale phenomena (e.g. tides) and smaller scale phenomena (e.g. gravity waves). Observations of both the tides and gravity waves will be presented. In addition, a study of the correlations between the irradiance and vertical wind, showing a correlation between the irradiance and the height of the airglow layer, will be presented.
        Speaker: Samuel Kristoffersen (University of New Brunswick)
        Slides
      • 359
        Imaging mesospheric winds using the Michelson Interferometer for Airglow Dynamics Imaging (MIADI)
        The Michelson Interferometer for Airglow Dynamics Imaging (MIADI) is a ground based optical instrument designed to obtain two dimensional images of the line of sight Doppler wind and irradiance field in the mesosphere. The intention of the instrument is to measure the perturbations in the airglow due to the presence of gravity waves. In its current configuration, the instrument observes a ~80 km x ~80 km region of the night sky in ~33 minutes using the O(1S) emission at 557.73 nm and the OH (6, 2) P1 (2) emission at 839.918 nm. The instrument was installed and tested at a field site outside Fredericton, NB (45.96 N, 66.65 W) during the summer of 2014. Successful measurements over a six hour period were obtained on July 31, 2014. Variations in the meridional and zonal wind were observed that are consistent with a semi-diurnal tide with an amplitude of ~ 35 m/s. Smaller scale variations (< 10 m/s) were also observed that indicate the presence of gravity waves. In this paper, the instrument concept will be presented and the results from the field measurements will be discussed.
        Speaker: Mr Jeffery Langille (UNB)
      • 360
        CAFTON and PEARL: Using Ground-based FTIR Spectroscopy to Probe Atmospheric Composition over Canada
        Fourier transform infrared (FTIR) spectroscopy provides a powerful tool for probing the atmosphere. Solar absorption spectroscopy can be used to measure atmospheric abundances of tropospheric and stratospheric trace gases, while emission spectroscopy also provides information about clouds and the radiation budget. High-quality time series of composition measurements, along with critical analysis and evaluation, are essential as a means to improve our understanding of the changing atmosphere. In Canada, FTIR measurements have been made for more than a decade at the University of Toronto Atmospheric Observatory (TAO) and since 2006 at the Polar Environment Atmospheric Research Laboratory (PEARL) in the high Arctic. These instruments, in combination with several other FTIR spectrometers, comprise the Canadian FTIR Observing Network (CAFTON). This network involves: (i) coordination and enhancement of FTIR measurement capabilities, (ii) implementation of new and improved methods for measuring atmospheric constituents, and (iii) use of models to investigate processes related to the origin, concentration, and transport of airborne contaminants. This presentation will provide a brief overview of CAFTON, with a focus on measurements at TAO and PEARL. Several applications of these measurements will be discussed, including identification of the sources of air pollution over Toronto, detection of smoke plumes from biomass burning events in the Arctic, and quantification of Arctic stratospheric ozone depletion.
        Speaker: Kimberly Strong (University of Toronto)
    • W2-6 Special session to honor Dr. Akira Hirose IV (DPP) / Session spéciale en l'honneur du Dr Akira Hirose IV (DPP) CAB 243

      CAB 243

      University of Alberta

      Convener: Ying Tsui (University of Alberta)
      • 361
        Solenoid-free Plasma Start-up in NSTX using Transient Coaxial Helicity Injection (CHI)
        Transient Coaxial Helicity Injection (CHI) in the National Spherical Torus Experiment (NSTX) has generated toroidal current on closed flux surfaces without the use of the central solenoid. When induction from the solenoid was added, CHI initiated discharges in NSTX achieved 1 MA of plasma current using 65% of the solenoid flux of standard induction-only discharges. In addition, the CHI-initiated discharges have lower density and a low normalized internal plasma inductance of 0.35, as desired for achieving advanced scenarios. These results from NSTX imply a current generation potential in excess of 500 kA in the NSTX-U currently nearing completion of a major upgrade to increase its device capability. Both conventional aspect ratio tokamaks and spherical tokamaks (STs) have generally relied on a central solenoid to generate the initial plasma current and then to sustain that current against resistive dissipation. However, in a steady-state reactor, induction alone cannot be used for plasma current sustainment. The inclusion of a central solenoid in a tokamak to provide plasma startup limits the minimum aspect ratio and increases the device complexity. For reactors based on the ST concept, elimination of the central solenoid is essential, making alternate methods for plasma start-up necessary for such a reactor. CHI [R. Raman, et al., PRL 104, 095003 (2010)] is implemented in NSTX by driving current from an external source along field lines that connect the inner and outer lower divertor plates. NSTX CHI simulations with the Tokamak Simulation Code (TSC) show that CHI start-up current scaling with toroidal field is consistent with present understanding of CHI theory, and this suggests that potential use of CHI on larger machines is quite attractive. These exciting new results from NSTX demonstrate that CHI is a viable solenoid-free plasma startup method for future STs and Tokamaks.
        Speaker: Dr Roger Raman (University of Washington)
      • 362
        Impacts of STOR tokamaks on fusion research
        STOR-1M and STOR-M tokamaks have been impacting a fusion research in two areas: [1] Alternating current (AC) operation, and [2] Central solenoid (CS)-less plasma current start-up in a tokamak. I would like to look back on these researches and talk about their possible future impacts. [1] AC operation in STOR-1M and STOR-M: In design of STOR-1M and -M tokamaks, the iron core image field was taken into account since Prof. Hirose derived a simple formula for the infinitely long cylinder of the iron core. The image field from the iron core transformer is measured by saturating the iron core in STOR-1M. This inspired the recent iron core saturable operation in STOR-M. AC operation was demonstrated in Feb. 1984, and the first paper was published in NF at 1987. Since then, AC operations have been conducted in JET (1992), STOR-M (1993), CSTN, ISTTOK, CT-6B and HT-7. In future, a D-T high aspect ratio tokamak with R=8~10 m could be operated by AC operation. Vertical field induction relaxes the AC operation condition for achieving equal AC discharge length by supplying an additional flux. [2] CS-less plasma current start-up in STOR-M: Based on our knowledge on iron core transformer obtained in STOR-1M and STOR-M experiments, the CS-less plasma current start-up has been demonstrated after removing CS in STOR-M at 2007. In 2012~2014 the active studies have been conducted, and it was demonstrated that the plasma current can be maintained during the iron core saturation phase. This type of discharge was first demonstrated in the world. This operation scenario can be applied specifically to an initial plasma current start-up in spherical tokamak (ST) reactor aiming at D-3He fusion.
        Speaker: Prof. Osamu Mitarai (Tokai University)
      • 363
        Compact Torus Injection for Fuelling
        Current fueling technologies, such as gas puffing or pellet injection, are unable to send fuels directly to the reactor core due to premature evaporation and ionization at the edge of the reactor. Compact torus (CT) injection as a means for fueling a magnetically confinement fusion reactor as a research topic at the University of Saskatchewan started in early 90’s. Compact torus formed in a magnetized coaxial gun is confined by the magnetic field self-induced by the current in CT. This robust high density plasmoid can be accelerated to a high velocity to penetrate the magnetic field gradient in tokamaks to reach the core of the reactor. Plasma Physics Laboratory built the first CT injector which demonstrated first disruption-free CT injection on TdeV. Soon after that, the University of Saskatchewan Compact Torus Injector (USCTI) was designed and built specifically to inject a low-mass CT into the STOR-M tokamak. Over the last two decades, USCTI has made several unique contributions to this research area. This talk will briefly summarize the results of the following experiments: a) demonstration of H-mode like discharge and MHD suppression induced by CT injection into the STOR-M tokamak, b) modification of plasma toroidal flow velocity towards the tangential CT injection direction, and c) demonstration of the record high frequency of repetitive CT formation. *supported by NSERC, CRC and SF-CCNI
        Speaker: Chijin Xiao (Univ. of Saskatchewan)
    • W2-7 Cosmic Frontier: Astrophysics and Neutrinos (PPD) / Frontière cosmique : astrophysique et neutrinos (PPD) CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Dr Guillaume Giroux (Queen's University)
      • 364
        Recent Results from IceCube
        The spectrum of cosmic rays includes the most energetic particles ever observed. The mechanism of their acceleration and their sources are, however, still mostly unknown. Observing astrophysical neutrinos can help solve this problem. Because neutrinos are produced in hadronic interactions and are neither absorbed nor deflected, they point directly back to their source. Neutrinos may also be produced in other astrophysical processes, such as WIMP annihilation, and the detection of such particles will allow insight into these processes. This talk will cover searches for high-energy neutrinos (> 10 TeV) at the IceCube South Pole neutrino observatory, which have lead to the discovery of a flux beyond standard expectations from neutrinos generated in the Earth's atmosphere. This includes the detection of events with energies above 1 PeV -- the highest energy neutrinos ever observed. In addition to astrophysical neutrino searches, IceCube’s lower energy threshold of about 10 GeV makes the detector a multi-purpose instrument, allowing us to study effects such as neutrino oscillation using atmospheric neutrinos. The talk will give an overview of the IceCube physics programme and will present recent results. In addition future detector extensions will be discussed.
        Speaker: Claudio Kopper (University of Alberta)
        Slides
      • 365
        Long-Term Stability of Backgrounds in the IceCube Neutrino Observatory
        The IceCube Neutrino Observatory is a cubic-kilometre-scale neutrino telescope completed in the Austral summer of 2010/2011. The detector forms a lattice of 5,160 photomultiplier tubes (PMTs) installed in the South Polar ice cap at depths from 1450 to 2450 m. IceCube is designed to detect astrophysical neutrinos upward of 100 GeV and to study neutrino oscillations with atmospheric neutrinos down to about 10 GeV thanks to the DeepCore infill array. In addition to this, the special environment of the Antarctic ice makes it possible to detect neutrinos of much lower energies (~10 MeV) from galactic core-collapse supernovae by measuring a correlated increase in PMT background rates. Especially these studies very close to the detector threshold require multi-year data samples to achieve statistically significant results. Investigating the long-term behavior of the backgrounds, mainly PMT noise and atmospheric muons, is therefore important to estimating the sensitivity and understanding variations in the background between different data samples. We find that the noise rate of the IceCube PMTs decays over multiple years and observe a yearly sinusoid-like variation in the atmospheric muon background. The decay can be attributed to changes conditions of the surrounding ice in which the PMT is embedded. Variations in the atmospheric muon background can be attributed to changes in the conditions of the upper atmosphere.
        Speaker: Benedikt Riedel (University of Alberta)
        Slides
      • 366
        Direct reconstruction - a new event reconstruction algorithm for the IceCube Neutrino Observatory
        The IceCube detector is designed to detect very high-energy neutrino events (exceeding 1 PeV) from astrophysical sources. DeepCore, a low-energy array, was designed to extend the reach of IceCube down to ~10 GeV. Data analyses at the low energies have unique challenges compared to their high-energy counterparts, including achieving robust reconstructions of the energy and angular properties in the sparsely instrumented detector volume. The traditional reconstruction algorithms are also reliant on large-memory tabulated representations of the photon probabilities in the instrumented ice that are technically difficult to produce. Here a new algorithm is described that takes advantage of parallelizing the simulation of event hypotheses across general purpose graphics processing units (GPUs), and directly propagating the resulting photons. In this way, events may be reconstructed in real-time with a full detector simulation, removing the need to approximate models of the detector medium and ultimately providing the best possible description of the neutrino interactions in the deep Antarctic glacier.
        Speaker: Sarah Nowicki (University of Alberta)
        Slides
      • 367
        Long-Term Supernova Monitoring with HALO
        Supernovae are the favoured location in the universe for certain processes necessary for the formation of heavy elements, and the only location where the effects of neutrino-neutrino scattering could plausibly be observed. This makes supernovae relevant to the fields of both nuclear astrophysics and particle physics. A core collapse supernova can be detected by the immense burst of neutrinos it produces. For this reason, HALO (Helium And Lead Observatory) was built to detect supernova neutrinos by capturing neutrons released from lead nuclei when struck by neutrinos. The use of lead as a target material gives the detector a unique sensitivity to electron neutrinos, where as other detectors predominantly see electron anti-neutrinos. The different neutrino flavor distributions could provide information about the structure and mechanics of the core-collapse. HALO will be joining the SNEWS (SuperNova Early Warning System) in the near future. SNEWS is a network of neutrino detectors around the world that will send an alarm to the astronomy community when a galactic supernova is detected. The surface of a supernova does not explode until the shock wave from the core collapse reaches it, which takes a few hours. Because of this delay, SNEWS can inform astronomers of a supernova before it is visible, which will hopefully allow for a supernova to be observed from its very beginning for the first time. HALO is expected to run continuously for decades in order to detect a supernova. This is important because most other detectors in the SNEWS network are not primarily focused on supernovae, and as such may be shut down for refurbishments aimed at other physics goals when a supernova occurs. An “always on” detector will remove the possibility that SNEWS misses a galactic supernova. HALO currently has a burst monitor running at low thresholds to learn more about the types of background events occurring in the detector. The most notable of these are Spallation events, caused by muons splitting lead nuclei. These events release bursts of neutrons with multiplicities well above the supernovae detection threshold, but they can be very cleanly discriminated due to their short duration and more spacial clustering in the detector. Other types of instrumental bursts are also noted and analyzed.
        Speaker: Mr Colin Bruulsema (Laurentian University)
        Slides
      • 368
        Atmospheric Neutrino Measurement with IceCube Neutrino Observatory
        IceCube, the world’s largest neutrino detector, is designed to measure the highest energy neutrinos produced in astrophysical events. Augmented with a low-energy array, called DeepCore, IceCube has the ability to perform precision measurements of the high flux of atmospheric neutrinos for energies ranging from approximately 10 GeV to a few 100 TeV. When combined with the measurements by Super-Kamiokande, it is possible to create a measurement of the atmospheric neutrino flux over 7 orders of magnitude. Discussed will be the development of the DeepCore analysis for performing a forward-folding measurement of the atmospheric flux in the crucial overlap region of the detectors between 10 GeV and 100 GeV.
        Speaker: Tania Wood (University of Alberta)
    • W2-8 Labs and/or undergraduate research experiences (DPE) / Expériences de recherche en laboratoire et/ou au premier cycle (DEP) CCIS L1-160

      CCIS L1-160

      University of Alberta

      Convener: Daria Ahrensmeier (Simon Fraser University)
      • 369
        A New format for Reporting in a First Year Physics Laboratory
        A new approach for the preparation and submission of laboratory reports for a first year Physics course has been developed at the University of Manitoba. Students are able to complete the data collection and analysis as well as the preparation and submission of the lab report during the three hour lab period. The students are provided with a template prepared in Microsoft Excel to help analyze their data and organize the report. The template includes separate tabs for each of the required sections of the lab report. One lab report per group of two students is submitted allowing the students more time to discuss the results, thereby enhancing the understanding and learning process. The lab report is saved as a PDF file and submitted via the Desire to Learn (D2L) system. Teaching Assistants download the lab report and mark it by adding their comments to the file. The marked lab report is uploaded using the feedback option in D2L. With this new approach the students are more aware of the purpose and outcome of the experiments. Late and missing lab reports are no longer a problem and the number of complaints included in the course evaluation has decreased significantly. The average lab mark has also shown an increase from previous years as the result of the modified format. The format is being adapted for the laboratory component of the other first year Physics courses. The new format will be illustrated with examples from experiments that are currently being done by the first year Science and Engineering students at the University of Manitoba. The outcome of the labs before and after introducing the modified format will be presented.
        Speaker: Dr Marzena Kastyak-Ibrahim (University of Manitoba)
      • 370
        Paperless physics laboratory course using the Blackboard resources.
        Creating a paperless laboratory course does not only mean "going green" involving a friendly attitude to environment, but gives a lot of new opportunities in achieving additional learning outcomes. Among the other important advantages of the paperless course are reducing the lab report preparation time for students and optimizing the grading process for TAs/Lab Demonstrators. The paperless laboratory course can be run as a traditional lab course as well as a student-centered learning class. Despite a widely spread opinion that the Blackboard facility is inconvenient, slow working and often out of service, this facility has a number of smartly developed features that can serve the paperless course very efficiently. The report is based on the author’s experience with introducing the paperless lab component to the 1st and 2nd year courses of Mechanics, Waves, Modern Physics, Quantum Physics and Thermal Physics at the University of Toronto in 2013 - 2015. The step-by-step lab report preparation, uploading, reviewing, grading and commenting are presented in detail with a demonstration of an example of a report going through the above listed stages. The specific learning outcomes are discussed. Students’ and TAs’ feedback obtained in regular surveys is presented and analyzed. (5) Innovations in physics education.
        Speaker: Natalia Krasnopolskaia (University of Toronto)
        Slides
      • 371
        **WITHDRAWN** Upper Level Undergraduate Physics Laboratories Competencies
        The undergraduate laboratory is an integral part of the physics curriculum because of the experimental nature physics as a discipline. The importance of the laboratory component in physics education cannot be overemphasized. Considerable efforts were made and resources invested in revitalizing the introductory undergraduate laboratories and integrating these experiences with the rest of the course components (such as studios, labatorials and practical setting) in many universities across Canada. There is a growing body of data pointing out how the effective introductory laboratories environment can be created and maintained. However, much less attention was devoted so far to the revitalization of the upper division undergraduate laboratories, despite the fact that these laboratories are providing the initial training to the students in STEM related disciplines that are crucial for the technological progress of the society We feel that the time is ready to open a discussion about the desired learning outcomes of advanced physics laboratories and mapping the ways to achieve them.
        Speaker: Dr Tetyana Antimirova (Ryerson University)
      • 372
        The University of Calgary Instructor of Record mentorship program: helping graduate students make the transition to becoming effective instructors
        For most graduate students, the only exposure to undergraduate teaching comes from interacting with students in a junior teaching laboratory or tutorial, or perhaps giving an individual lecture to cover the absence of a faculty member. When graduate students eventually become instructors, they are given the challenging task of teaching a lecture section without much experience and with virtually no formal instruction in this very different learning environment. In this situation, junior instructors are faced with preparing coherent lectures and leading a large group of students in the discovery and understanding of basic Physical concepts. In order to help select graduate students gain experience, the Department of Physics and Astronomy at the University of Calgary is pioneering its own mentorship and instructional experience program, which enables PhD students who are in the final stages of their degree to assume the full responsibility for a lecture section of a first-year introductory Physics course (to date an introductory course on mechanics). Under the guidance of experienced faculty members, the graduate student is responsible for the preparation and delivery of a full set of lecture sessions for one term. In collaboration with experienced physics instructors and broader experts in teaching development, the graduate students receive ongoing mentorship throughout the term and feedback on their lectures twice during the semester. This provides them with the opportunity to try different teaching strategies in the classroom and receive constructive criticism on the effectiveness of their work. After two years, and four graduate student instructors of record, the feedback from participants has been highly positive. Classroom observations reveal that the young instructors are receptive to suggestions to improve their instruction and quickly develop important teaching skills that help them become successful teachers. This presentation will provide an overview of the evolving structures and processes used in this program, as well as a discussion of the strengths, successes, and challenges that we found over its now two years of operation.
        Speaker: Michael Wieser (University of Calgary)
      • 373
        Making Comparisons - A Strategy for Teaching Scientific Reasoning in a First Year Lab
        Recent work on first year labs at UBC have focussed on teaching students widely-applicable data handling skills: especially, understanding uncertainty, statistical tools, and graphical techniques. In the past year we have also targeted students' critical thinking, with a relatively simple framework that asks students to make quantitative comparisons, reflect on those comparisons, and then act on them. These iterative loops force students to improve their experiments and/or re-think the models they are testing. We have found that these expert behaviours become a habit-of-mind even after the explicit instructions to iterate are removed. More importantly we find that when combined with experiments that force them to confront problems with models, these iterative comparison loops lead to striking improvements in the quality of students' reflection on data and models. These gains are also found to transfer into their behaviour in second year, a striking instance of transfer.
        Speaker: Prof. D.A. Bonn (University of British Columbia)
      • 374
        Off with the training wheels: Student centered approach to lab work.
        Do you remember those labs in college when you just followed your teacher's instructions? You probably barely do right? In order to increase students' involvement in the scientific process (and to increase motivation), I tried a different approach. I trained them to become autonomous researchers. At first, I gave them detailed instructions and complete theoretical framework. Then gradually, I moved to providing them only with the goal of the experiment. They had to research the theoretical aspects and decide how to take the measures. At last, they were asked to come up with their own research project, conduct their experiment and share their results. This presentation will cover every step of the training from the documentation provided to students to typical research projects, with an emphasis on the time and amount of work required (from both teacher and students).
        Speaker: Mr Benoit Blanchet (Cégep de Rivière-du-Loup)
        Slides
    • W2-9 General Instrumentation and Measurement Physics (DIMP) / Physique générale des instruments et mesures (DPIM) CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Kirk Michaelian (Natural Resources Canada)
      • 375
        A review of imaging methods in analysis of works of art. Thermographic imaging method in art analysis.
        Methods of non-destructive analysis and quality control are an inherent part of progress in development of modern materials for science and industry. Many of these methods and techniques find new, sometimes unexpected, applications in other fields as well. This presentation is devoted to an outline of those imaging methods which made their paths from science and industry to the delicate world of artworks in order to give art scientists and conservators the power of high-precision defectoscopy and structure evaluation. Among the methods discussed are such senior techniques as X-ray radiography, infrared imaging in different wavebands, and others, as well as more “exotic” approaches such as acoustic and different kinds of thermographic imaging.
        Speaker: Dr Dmitry Gavrilov (University of Windsor, Windsor, Canada)
      • 376
        Making and using atomically defined nanotips
        Atomically defined tips gained significant attention over the past decades to be used as gas field ion sources (GFISs) for helium ion microscopy (HIM) and non-staining ion beam writing applications, electron sources for high resolution SEM, TEM and electron holography, as well as scanning probe microscopy, namely STM and AFM. Single atom tips (SATs) represent a unique subgroup of atomically defined tips where nanotip apex is terminated by a single atom. In this presentation we will review field ion microscopy (FIM) technique to visualize individual surface atoms of sharp probes and discuss etching process to form atomically sharp nanotips. We will outline characterization methods to evaluate nanotip shape and performance as high brightness GFIS. We will also present scanning probe microscopy images demonstrating unique properties of single atom nanotips.
        Speaker: Radovan Urban (University of Alberta)
      • 377
        Performance Assessment of a Silicon-Based Piezoresistive MEMS Strain Sensor
        The performance of a silicon-based MEMS strain sensor was assessed using static and dynamic strain. Static strain response of the sensor was tested under static bending and uniaxial loading conditions. Dynamic strain response was evaluated at frequencies of 10 Hz, 63 Hz, and 175 Hz using an aluminum cantilever beam mounted on an electrodynamic shaker. The static strain response showed that the sensor has a gauge factor of 13.0 and sensor sensitivity of 65 μV/με at 3.0 V-excitation. The dynamic strain response included some electrical noise in the sensor output signal. Comparison with a reference resistive foil gauge shows that the foil gauge and MEMS sensor have comparable dynamic response at the frequencies tested. Extended vibration testing demonstrated sensor lifetime of 2.7 million cycles at an equivalent strain of 1291.0 με
        Speaker: Mr Ronald Delos Reyes (University of Alberta, Department of Chemical and Materials Engineering)
      • 378
        The Saskatchewan Centre for Cyclotron Sciences: Developing a multi-use cyclotron facility
        The Sylvia Fedoruk Canadian Centre for Nuclear Innovation (Fedoruk Centre) is in the process of commissioning the Saskatchewan Centre for Cyclotron Sciences as a multidisciplinary research and commercial radiopharmaceutical production facility. At the heart of the facility is a multipurpose 24 MeV cyclotron capable of producing a number of radioisotopes for use in research in humans, animals and plants as well as to supply clinical needs for PET-CT scans. Envisioned as a user facility, the Saskatchewan Centre for Cyclotron Sciences enables the growth of the nuclear imaging research community in Saskatchewan and beyond in fields ranging from the development of novel molecular imaging probes to detector design. This paper provides an overview of the vision and structure of the Saskatchewan Centre for Cyclotron Sciences and outlines the opportunities for research collaboration provided by the facility and the Fedoruk Centre.
        Speaker: Sara Ho (Saskatchewan Centre for Cyclotron Sciences)
    • Health Break (with exhibitors) / Pause santé (avec exposants) CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • W-MEDAL1 CAP Medal Talk François Légaré, EMT-INRS (CAP Herzberg Medal Recipient/Récipiendaire de la médaille Herzberg de l'ACP) CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Robert Fedosejevs (University of Alberta)
      • 379
        A new strategy to build ultrafast lasers; Frequency domain Optical Parametric Amplification
        High power laser amplification of octave spanning or even octave exceeding spectra is a formidable technological challenge since the universal dilemma of gain narrowing is only one of many problems on this path. The shortcoming of all present femtosecond (1fs = 0.000000000000001s) laser amplification schemes suffer from opposing conditions for either high amplification level (=> high peak power), or large amplification bandwidth (=> short pulse duration). Therefore, amplified pulses at the output of laser systems are typically limited to >5 optical cycles pulse duration at best. To overcome the universal dilemma of gain narrowing which prevents ultra high power lasers from delivering single to few-cycle pulses, a new amplification concept is proposed; Frequency domain Optical Parametric Amplification [1,2]. One cycle of the electric field in time domain corresponds to an octave of frequencies in the spectral domain. The key idea for amplification of octave-spanning spectra without loss of frequencies is to amplify the broad spectrum “slice by slice” in the frequency domain. Opposed to traditional schemes where laser amplification takes place in the time domain, we propose to amplify different spectral parts independently of each other in the spectral domain of a 4f-setup. For the first time, simultaneous up-scaling of peak power and amplified spectral bandwidth became possible. The device can be operated at any wavelength of conventional laser amplifiers, however, with the capability to amplify single optical cycle of light. A working laboratory prototype built at the Advanced Laser Light Source (ALLS) delivered record breaking parameters in the field of infrared few-cycle lasers; carrier envelope phase (CEP) stable pulses carrying 1.5 millijoule (mJ) of energy with 12 fs duration (= two optical cycles) at 1.8 micron wavelength. [1] B. E. Schmidt, N. Thiré, M. Boivin, A. Laramée, F. Poitras, G. Lebrun, T. Ozaki, H. Ibrahim, and F. Légaré (2014, Frequency domain optical parametric amplification, Nature Comm. doi:10.1038/ncomms5422). [2] P. Lassonde, N. Thiré, L. Arissian, G. Ernotte, F. Poitras, T. Ozaki, A. Larameé, M. Boivin, H. Ibrahim, F. Légaré, B. E. Schmidt (2015, High gain Frequency domain Optical Parametric Amplification, accepted at IEEE Journal of Selected Topics in Quantum Electronics 10.1109/JSTQE.2015.2418293).
        Speaker: Francois Legare (INRS-EMT)
    • W-MEDAL2 CAP Medal Talk - John F. Martin, IPP / U. Toronto (Achievement Medal Recipient / Récipiendaire de la médaille pour contributions exceptionnelles) CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Robert Fedosejevs (University of Alberta)
      • 380
        From Quarks to Neutrinos, Adventures in Particle Physics
        I have been fortunate to participate in the evolution of particle physics in Canada for a large fraction of its history. I will discuss developments from 1972 to its current lively state, illustrating with a few examples from the experiments on which I have collaborated. With the recent discovery of the Higgs boson the Standard Model is now complete, but is known to be an incomplete description of nature. The questions before us have never been more interesting, and the increasingly complex experiments in subatomic physics and cosmology should soon yield exciting new discoveries about the universe.
        Speaker: John Martin (Department of Physics and Astronomy)
        Slides
    • CAP President's report / Rapport du président de l'ACP CCIS 1-430

      CCIS 1-430

      University of Alberta

      Convener: Robert Fedosejevs (University of Alberta)
    • CAP Annual General Meeting with election of Board and Advisory Council members/ Assemblée générale annuelle de l'ACP avec election des membres du c.a. et du conseil consultatif CCIS 1-430

      CCIS 1-430

      University of Alberta

    • "Friends of CAP" Dinner and Meeting / Souper et réunion des "Ami(e)s de l'ACP" CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Kenneth Ragan (McGill University)
    • DAMOPC Poster Session with beer / Session d'affiches avec bière DPAMPC CCIS Ground Floor PCL lounge

      CCIS Ground Floor PCL lounge

      University of Alberta

      Convener: Chitra Rangan (U)
      • 381
        Two-dimensional accelerating beams along arbitrary trajectories and enhancement of their peak intensities
        In the last few years, accelerating optical beams propagating along a curved trajectory have attracted a lot of attentions. Since Airy beams were the first to be introduced into optics, they have been employed in a variety of applications, such as the generation of curved plasma channels, optical trapping and manipulation, and micro-fabrication. It has been shown that accelerating beams can be designed to propagate along arbitrary convex trajectories through engineering the phase of a light wave in either real or Fourier space. However, most of the work thus far focused on one-dimensional configurations only, with the emphasis on the engineering of beam trajectories. The dynamics of two-dimensional (2D) accelerating beams, a useful knowledge for practical applications, has not been investigated in a general way. In this work, we study analytically and experimentally the dynamics of two dimensional accelerating beams generated from the Fourier-space phase modulation of a light. We demonstrate that the trajectory of a 2D accelerating beam can be designed from a direct mapping between the spatial spectrum and the propagation distance. In addition, the main lobe of the beam can be approximately described by an analytical solution in a generalized way. Moreover, we also propose a method to optimize the accelerating beam generation, aiming at obtaining enhanced peak intensities. Our theoretical analyses are in good agreement with the experimental results. Our findings may be relevant to many applications as mentioned in the introduction.
        Speaker: Luca La Volpe (INRS)
      • 382
        Pulsed Laser Spectroscopy of Xe129 for a Co-magnetometer in the TRIUMF Neutron Electron Dipole Moment Experiment
        Construction is underway at TRIUMF by an international collaboration on a high-density ultra-cold neutron source. Its primary experiment will be a measurement of the neutron electric dipole moment (nEDM). The experiment uses an NMR technique known as Ramsey resonance to detect electric-field correlated shifts in the precession frequency of ultra-cold neutrons. Previous-generation nEDM experiments add spin-1/2 Hg$^{199}$ atoms as a co-magnetometer in the same volume with ultra-cold neutrons to perform a cross-check on magnetic field drifts. Xe$^{129}$ is another spin-1/2 species sensitive to magnetic field drifts. We are developing magnetometry using Xe$^{129}$ atoms excited via two-photon transitions at 252 nm and detecting the laser-induced fluorescence(LIF). Combining both Hg$^{199}$ and Xe$^{129}$ co-magnetometers will make it possible to measure and correct for geometric phase effects which currently limit the accuracy with which field instabilities are measured. Xe$^{129}$ has been studied in the past using the spin exchange optical pumping technique, which hyperpolarizes the gas orders of magnitude greater than achievable in Boltzmann distributions alone, but requires Rb for optical interaction. Our goal in investigating the two-photon transition is to optically pump and probe a spin state of Xe$^{129}$ directly. One of the hyperfine transitions is sensitive to the excitation light’s polarization and suitable for optical pumping. While a narrow-linewidth CW laser is the ideal for measuring this sensitivity, intensity requirements for TPA necessitate use of (broadband) pulsed nanosecond lasers. We will present results from Doppler-free studies of the 252 nm transition and polarization dependence, as well as observed coherent emission of LIF radiation.
        Speaker: Eric R Miller (The University of British Columbia)
      • 383
        Ultracold gas coupled to a nanomechanical resonator via Zeeman interaction
        A strong need for computational power as well as limits of classical computers has led to the development of quantum information science. One of the critical problems in realizing quantum computing is manipulating quantum bits while maintaining coherence. One of the possible solutions is to use a hybrid system that combines the long coherence times available in microscopic quantum systems with the strong interactions and integration available in solid state systems. Studying such systems can help to investigate ways to reduce decoherence and apply the results for quantum information processing. In our lab we are building a system to study coupling of nanomechanical resonator to a cloud of ultracold Rb atoms in a Bose-Einstein condensate (BEC). Condensed state is achieved by means of laser and evaporative cooling. Condensate will be placed in an optical trap above the tip of a cantilever-type resonator. The tip carries a single-domain ferromagnet which creates a dipole-like magnetic field. The tip oscillations create an oscillatory component of the magnetic field, which provides coupling to the atomic spin via the Zeeman interaction. When the frequency of the resonator mode matches the Larmor frequency corresponding to the hyperfine structure of Rb, the coupling induces spin flips. This can be detected by observing the loss of atoms from the trap. This technique allows one to probe thermal motion of the cantilever at room temperature. At low resonator temperatures the spin back action determines the resonator motional state analogously to cavity quantum electrodynamics. In this regime BEC can be used to actuate the resonator motion or to provide entanglement with another resonator.
        Speaker: Andrei Tretiakov (University of Alberta)
      • 384
        Application Of An Optical Parametric Oscillator For Infrared Spectroscopy Of Jet-Cooled Molecules And Complexes.
        Van der Waals interactions are fundamental for molecular reactions such as aerosol formation, adsorption of atoms and molecules on surfaces, protein conformation and many more. Infrared absorption spectra of weakly-bound van der Waals complexes provide the necessary information to develop inter-molecular potential energy surfaces. During the past five years, our group has been systematically investigating the infrared spectra of weakly bound dimers and larger clusters formed from CO2, N2O, OCS, CS2 and C2H2.The goal is to collect spectroscopic data against which theory can be benchmarked. In 2013 our group developed and implemented a state of the art Optical Parametric Oscillator (OPO) based spectrometer for studying these intermolecular forces. The work presented will aim to explain the implementation of this OPO system and the process through which data is acquired. The main parts of the system, such as the cluster formation, probe laser and data processing, will be explained. Lastly some of the results will be shown demonstrating the efficacy of this method and the reliability of our setup as source for high-resolution and high-sensitivity spectroscopy of van der Waals molecular complexes.
        Speaker: Mr Luis Carlos Welbanks Camarena (University of Calgary)
      • 385
        Using radio frequency radiation to discover new effects in ultracold gases
        One of the most important achievements in physics during recent years is the ability to create a Bose-Einstein Condensate (BEC) in neutral atoms. The study of BEC gives us an opportunity to discover new physics phenomena, to probe the laws of quantum mechanics and to better understand enigmatic world of small particles. A very powerful tool for these purposes is quantum simulation of interacting many-body systems. To create BEC, very low temperatures are needed. After laser pre-cooling, Radio-frequency (RF) induced evaporative cooling is used. RF evaporation of atoms in a trap is based on coupling the trapping state to a non-trapping state with a radio-frequency field. As a result of such coupling, it is possible to control the height of the trap by changing RF frequency. With decreasing the height, the most energetic atoms will leave the trap. After thermal relaxation, when the hottest atoms are located on the top of the trap, such process can be repeated. By using evaporative cooling the coldest temperatures in the Universe could be reached. Similar techniques can be used to modify internal atom states for implementation new spin-orbit coupling schemes that will open new possibilities to quantum simulation of strongly correlated condensed matter system. These techniques are very promising for extending spin-orbit coupling to two or more dimensions. To modify the internal quantum states of the atoms we develop the radio and microwave frequency electronics (including control and transmission). The project will begin with the design and testing of these electronics, followed by the calibration of their effects on the ultracold quantum gases, and finally, to use these fields to create a spin-orbit coupling in the atomic quantum gas.
        Speaker: Taras Hrushevskyi (University of Alberta)
      • 386
        Development of a High Intensity Yb:YAG Pumped Optical Parametric Chirped Pulse Amplification Laser System
        High intensity laser systems are finding many new applications in MeV to GeV particle generation and acceleration to Fast Ignition pulses for Laser Fusion Energy Drivers. In some cases, in order to enhance the electric fields associated with the laser plasma interactions longer wavelengths are advantageous. Thus, there is considerable interest in the development of high intensity systems in the infrared part of the spectrum. In the current study we are developing a TW class optical parametric chirped pulse amplifier (OPCPA) system. The pump laser for this system will consist of a femtosecond Yb:glass oscillator which will be stretched to the order of 100ps and amplified in a diode pumped Yb:YAG ceramic slab amplifier system up to an energy of around 2 J. A seed pulse for the OPCPA system at a wavelength of around 1500nm will be created from white light continuum generated from the femtosecond pulse after amplification to the microjoule level. This seed pulse will be stretched and amplified in several stages of optical parametric amplification to a final energy of the order of 400mJ. The final pulse will then be recompressed to a pulse duration of the order of 100fs to give a 4 TW output pulse. The proposed system design and initial development tests will be presented and discussed.
        Speaker: Mohammed Eltahlawy (University of Alberta)
        Poster
      • 387
        Proposal of creating spin cat states in Bose-Einstein condensates
        Lots of efforts are currently made in many areas to bring quantum effects to the macroscopic level. A particularly dramatic class of macroscopic superposition states are the so-called cat states, which has been demonstrated in experiment with over one hundred microwave photons. In our recent works, we have proposed an experimental scheme to create spin cat states in Bose-Einstein condensates (BEC) with the possibility of cat sizes of hundreds of atoms based on detailed study of atom loss [Lau et. al, PRL 113, 090401 (2014)]. Our scheme relies purely on the Kerr nonlinearity due to atomic collisions in BEC with two different hyperfine states. We show that with suitable choice of system, magnetic field and high trapping strength, it is possible to significantly increase the Kerr effect while suppressing the two-body loss. This results in small overall loss and fast cat time, hence, a large spin cat state. The existence of cat states can be proved by the homodyne detection on the optical readout. Our analysis also includes the effects of higher-order nonlinearities, atom number fluctuations, and limited readout efficiency.
        Speaker: Hon Wai Lau (IQST, Univeristy of Calgary)
      • 388
        **WITHDRAWN** Particle vs. Mode Entanglement in Quantum Enhanced Optical Metrology
        We describe the role of mode and particle entanglement in Quantum Enhanced Optical Metrology (QEOP). To this end we study the properties of the quantum Fisher information $\mathfrak{F}$ that bounds from below the sensitivity $\Delta^2 \varphi$ of any phase estimation protocol $\Delta^2 \varphi \geq 1/\mathfrak{F}$. We recently showed [1] that the optimal measurement sensitivity of quantum light in a path symmetric Mach-zender interferometer depends on its inter-mode correlations and intra-mode correlations in the following manner $ \mathfrak{F}=\bar{n} (1+\mathcal{Q})(1-\mathcal{J})$ where $\bar{n}$ is the total number of photons in the MZI (assumed to be equally distributed in both arms), $\mathcal{Q}$ is the Mandel $\mathcal{Q}$ parameter (assumed to be the same for the two modes) and $\mathcal{J}$ is the mode correlation parameter. The intra-mode correlations in the form of non-classical counting statistics associated with the $\mathcal{Q}$ parameter of each arm of the interferometer are identified with particle entanglement whereas the inter-mode correlations in term of $\mathcal{J}$ are associated with mode entanglement. We discuss the effects of each type of entanglement in phase estimation and show that mode entanglement is not necessary for quantum enhanced sensitivity and that particle entanglement is always necessary for an enhancement, but, it is also always necessary for a suppression of sensitivity. In more general terms we show that particle entanglement does not fit the usual notions of a resource for QEOP since one can map states that are useful for QEOP to states that are not via particle local operations. [1] J. Sahota and N. Quesada, Phys. Rev. A **91**, 013808 (2015)
        Speaker: Nicolas Quesada (University of Toronto)
      • 389
        RECENT LINE-SHAPE STUDIES INVOLVING TRANSITIONS OF ACETYLENE BROADENED BY CARBON DIOXIDE
        The line parameters for transitions of acetylene broadened by carbon dioxide are needed for studies of planetary atmospheres that have a high content of carbon dioxide. carbon dioxide-broadened line widths and nitrogen-pressure induced line shifts have been measured for transitions in the band of acetylene located at 1.53 microns at seven temperatures in the range 213–333K to obtain the temperature dependences of broadening and shift coefficients. Several line profile models were used to retrieve the line parameters.
        Speakers: Li-Hong Xu (University of New Brunswick), Ronald Lees (University of New Brunswick)
      • 390
        Detection of Trace Gases using Fiber Laser Technology- Part 2
        Fiber-optic sensors based on fiber Bragg gratings have been established as rugged and reliable devices and have found applications in environmental monitoring, oil and gas reservoir monitoring, and in performing temperature, pressure, and strain measurements. However, new sensors with higher sensitivity, greater accuracy, and a simpler design, using fiber laser technology, would provide significant cost benefits and performance to the end user. The authors have developed a device, based on fiber laser technology, to detect trace gases. An erbium-doped fiber was used as the gain medium. For the collection and detection of trace gases, a gas cell was used inside the laser cavity. The authors will present the structure of the device and its working principle. The device was very sensitive and could detect gas at very low levels. The research work is supported financially by Natural Sciences and Engineering Research Council of Canada and Agrium, Canada.
        Speaker: Mr Jonas Valiunas (Lakehead University)
      • 391
        Numerical Analysis of Er-doped DFB Fiber Laser: Er ion Concentration and Output Power Optimization
        In this paper the dependence of Er-doped distributed feedback (ED-DFB) fiber laser output power on Erbium ion concentration is investigated theoretically. Numerical results show that by increasing ion concentration, the output power reaches a maximum and decreases for very high ion concentrations due to homogeneous up-conversion effect. Maximum value of output power of the ED-DFB fiber laser depends on the pump power and takes place at different concentrations. It is shown that the up-conversion effect gives rise to an increase in the pump power threshold. The structure of the DFB fiber laser considered in this work is 5 $cm$ long with a phase shift of $\pi /2$ at the center of the grating. The up-conversion effect is modeled by adding a term to the rate equations. Numerical calculations are performed by self-consistent solution of rate equations and coupled wave equations using transfer matrix method for $\lambda=1.55 \mu m$.
        Speaker: Jalal Norooz Oliaee (Department of Physics and Astronomy, University of Calgary, Calgary, Canada)
    • DASP Poster Session with beer / Session d'affiches avec bière DPAE CCIS Ground Floor PCL lounge

      CCIS Ground Floor PCL lounge

      University of Alberta

      Convener: Prof. Richard Marchand (University of Alberta)
      • 392
        Changes in Global Precipitation from 1850 to the Present
        Reports of the Intergovernmental Panel on Climate Change have stated that precipitation has changed by up to 1% for each decade in the 20th century [1]. Indeed, the Clausius Clapeyron equation predicts absolute humidity increases by about 7% for each degree of warming assuming no change in the relative humidity. This study analyzed monthly precipitation observations recorded at over 1,000 stations located around the world. Each station had a minimum of 100 years of observations and the data at some stations extended into the 1700s. The data were first examined for inhomogeneieties that can arise due to changes in instruments and/or data taking procedure. The annual precipitation total was only found if all 12 monthly values had been recorded. For each station, the percentage precipitation change compared to the period 1961-1990 was found. These changes were then averaged over all stations of each continent. The data was also examined for effects of latitude, seasons and whether stations were in desert or wet areas. The results show no statistically significant change in precipitation from 1850 to the present. 1. Climate Change 2001: The Scientific Basis, Intergovernmental Panel on Climate Change
        Speaker: Ms Atifa Syed (Physics Department, York University)
      • 393
        Possibility of determining predominant SO2 oxidation pathways by isotope fractionation or source apportionment
        Sulfur dioxide oxidation and the effect of oxidation products in formation and growth of aerosols have been studied widely. Despite this, significant gaps still exist in understanding the SO2 oxidation pathways in various locations. A study of SO2 and aerosol sulphate downwind of the oil sands region was conducted as part of the FOSSILIS campaign in the summer 2013. Size segregated aerosols have been collected using a high volume sampler. Sulphate concentration in different size ranges has been determined and isotopic analysis has been performed to determine whether isotope fractionation or source apportionment can be used to identify secondary aerosols and to determine predominant SO2 oxidation pathways in oil sands region.
        Speaker: Mrs Neda Amiri (Department of Physics and Astronomy, University of Calgary)
      • 394
        Characterization of Ionospheric Scintillation at High Latitude
        The chaotic behavior of the space plasma in the polar region is analyzed and characterized. The study was carried out using the amplitude and phase components of the GPS (Global Positioning System) L1 signal time series sampled at 50 Hz. A stationary signal is obtained after removing the trend due to the background electron density variability and the Doppler shift due to the satellite motion. The filtering is performed using the wavelet transform. The cutoff frequency is optimized by investigating the behavior of the Tsallis entropy of the system for different scales. The construction of the probability density functions of the phase and amplitude fluctuations and the estimation of the corresponding higher order moments are used to quantify the phase and amplitude fluctuations of the signal. The results reveal a general non-trivial parabolic relationship between the normalized fourth and third moments for the amplitude of the signal. A multi-fractal analysis of the power fluctuations of the L1 GPS signal is also presented. We consider the differential signal for different time lags. Probability density functions are computed and fitted with the Castaing distribution. Higher order moments of the distributions are used to investigate the intermittent nature of the signal. The present work reveals the direct evidence that the intermittent aspect of the investigated events is more pronounced at small temporal scales than at long ones.
        Speaker: Mr Hichem Mezaoui (University of New Brunswick)
      • 395
        Comparison of IGS Network GPS Receiver DCBs Provided by CODE and a Single Station Estimation Method
        The Global Positioning System (GPS) is a valuable tool in the measurement and monitoring of ionospheric total electron content (TEC). To obtain accurate GPS-derived TEC, satellite and receiver hardware biases, known as differential code biases (DCBs), must be removed. A number of sources calculate and provide GPS satellite DCBs, one such source is the Centre for Orbit Determination in Europe (CODE). CODE also provides monthly averages of receiver DCBs for a number of stations within the International GNSS Service (IGS) network. However, utilization of these DCBs can create discontinuities and inaccuracies in the unbiased TEC. A comparison of the monthly receiver DCBs provided by CODE with DCBs estimated using the Minimization of Standard Deviations (MSD) method [1], on both daily and monthly time scales, is presented. The comparison is performed using eight collocated station sets within the IGS network. Regardless of receiver hardware, TEC calculated from collocated receivers should provide identical results if the biases are correctly removed. Therefore, the difference between the respective unbiased receiver-derived TEC is calculated and compared. MSD derived DCBs, for both monthly and daily time scales, result in consistently lower differences between collocated TEC measurements than differences obtained using CODE-derived DCBs. Differenced TEC, unbiased using CODE-derived DCBs, are typically on the order of 2 TEC units (TECU) larger than their MSD counterparts. Daily MSD-derived DCBs also show fluctuations within the monthly intervals, with standard deviation values typically on the order of 2 - 5 TECU. These fluctuations allude to a time dependence in receiver DCB and introduces a possible need for bias estimation over smaller time intervals. These fluctuations are very well correlated between collocated receivers regardless of receiver make and model. This suggests that the receiver DCBs are affected by more than just the receiver hardware. [1] Ma, X. F., T. Maruyama, G. Ma, and T. Takeda (2005), Determination of GPS receiver differential biases by neural network parameter estimation method, Radio Sci., 40, RS1002, doi:10.1029/2004RS003072.
        Speaker: Anthony McCaffrey (University of New Brunswick)
      • 396
        Ionospheric Sounding Opportunities Using Signal Data From Pre-existing Amateur Radio And Operational Networks
        Amateur radio and other signals used for dedicated purposes, such as the Automatic Position Reporting System (APRS) and Automatic Dependent Surveillance Broadcast (ADS-B), are signals that exist for another reason, but can be used for ionospheric sounding. Whether mandated and government funded or voluntarily constructed and operated, these networks provide data that can be used for scientific and other operational purposes which rely on space weather data. Given the current state of the global economic environment and fiscal consequences to scientific research funding in Canada, these types of networks offer an innovative solution with pre-existing hardware for more real-time and archival space-weather data to supplement current methods, particularly for data assimilation, modelling and forecasting. Furthermore, the mobile ground-based transmitters offer more flexibility for deployment than stationary receivers. Numerical modeling has demonstrated that APRS and ADS-B signals are subject to Faraday rotation as they pass through the ionosphere. Ray tracing techniques were used to determine the characteristics of individual waves, including the wave path and the state of polarization at the satellite receiver. The modeled Faraday rotation was computed and converted to total electron content (TEC) along the ray paths. TEC data can be used as input for computerized ionospheric tomography (CIT) in order to reconstruct electron density maps of the ionosphere. The primary scientific interest of this study was to show that these signals can be used as a new source of data for CIT to image the ionosphere, possibly other data assimilation models, and to obtain a better understanding of magneto-ionic wave propagation.
        Speaker: Alex Cushley
      • 397
        Determining the equatorial dayside plasma density using travel-time magnetoseismology
        Plasma density in the outer terrestrial magnetosphere is highly variable, both in space and time. Spacecraft observations are very sparse, and photoelectric charging makes direct in-situ measurements extremely challenging. In this report we present a new remote sensing method which could be a significant source of information about conditions in the dayside magnetosphere. This technique uses a novel approach to travel-time magnetoseismology based on the relationship between solar wind pressure and magnetospheric currents. Travel-time magnetoseismology has had previous success in the inner magnetosphere and our approach adapts it for use for the outer magnetosphere. Observed time delays between solar wind forcing and response at geostationary orbit are attributed to compressional mode propagation in the equatorial plane. Alfvén speeds are modeled using a dipole geomagnetic field and plasma density profiles from the IGRF and Gallagher et al. Preliminary results show very good agreement between the model and observations. Future work will include the application of inversion techniques to recover 2D maps of equatorial plasma density in the dayside magnetosphere.
        Speaker: Mr Robert Ridgway (University of Calgary)
        1
      • 398
        A Statistical Study of Drifts of Patchy Pulsating Aurora:Observed by THEMIS All-Sky Imagers
        Patchy pulsating aurora (PPA) is a very common ionospheric phenomenon and thus offers us a unique opportunity to study the inner magnetospheric dynamics. It is usually excited by a few to 10s Kev electrons and occurs in the equatorward part of the auroral oval. Many previous studies have been done to investigate the motion of PPA patches, but none of them were based on a large dataset. In this study, we use data during May 2006 through July 2013 obtained from THEMIS all-sky imager at Gillam station (66.18 magnetic latitude, 332.78 magnetic longitude) to explore the statistical behavior of PPA and the motion of PPA patches. The statistical result of PPA patch motions showing that PPA patches mostly move westward in pre-midnight and move eastward in post-midnight, which is similar to the motion of ionospheric convection, has a great agreement with previous studies. Also, individual PPA cases have been analyzed to show the spatial and temporal evolution and variations of the motion of PPA patches, which suggests that PPA patches would provide us a great method to derive the electric field and remote sense the magnetospheric convection in high resolution both in time and space scale.
        Speaker: Bing Yang (University of Calgary)
      • 399
        Distribution of Gravity Wave Parameters over Eureka, Nunavut using the All Sky Imager
        This work will present the analysis approach developed to detect of gravity waves and the variation in gravity wave parameters deduced from the airglow images taken by the Polar Environment Atmospheric Research Laboratory (PEARL) All Sky Imager (PASI). PASI has been in operation since November 2007 at PEARL in Eureka, Nunavut with images being taken on average every minute during the winter seasons. An automated data analysis approach has been developed to diagnose the gravity wave parameters in a time efficient manner. PASI is a CCD imaging system with six different spectral band narrow band filters. The filters of interest in this research isolate the following airglow emissions: atomic sodium (at 589.3 nm), atomic oxygen green line (at 557.7nm), and hydroxyl (at 720-910nm notched at 865nm due to the molecular oxygen). PASI cycles through the different filters with the hydroxyl filter interleaved between the other filters in the sequence. The gravity wave parameters to be presented are the horizontal and vertical wavelength, intrinsic period and propagation direction. In each image occurrences of these waves are defined in terms of horizontal spatial wavenumber and phase. Temporal phase information is deduced from consecutive images which contain wave signatures with similar horizontal wavenumbers. The vertical wavelength is determined from consecutive images between the different airglow emissions using an approach similar to determining the temporal phase. This work will present monthly variations of these parameters along with their uncertainties for several seasons. In particular, the daily variation in gravity wave occurrence during the January 2009 major stratospheric warming will be highlighted.
        Speaker: Chris Vail (University of New Brunswick)
        Poster
      • 400
        Motion of the Polar Cap Arcs and Associated Plasma Flows
        Arc-like auroral structures in the polar cap often move in the dawn-dusk direction. Speeds of such motions vary between ~100 m/s and 2 km/s depending on the magnetic local time of observations. In the midnight sector, typical speeds of 300-500 m/s have been reported. We show that these values are somewhat larger than plasma flow speeds in the zonal direction typically observed by the Clyde River SuperDARN HF radar. This raises a question whether the zonal motion of the polar cap arcs is consistent with the projection of the ExB plasma velocity on the direction of the shift. In this study, we consider several events of the polar cap arc monitoring with the Resolute Bay 630 nm all-sky imager and concurrent measurements of the plasma flow with the PolarDARN/SuperDARN HF radars and Resolute Bay–North AMISR incoherent scatter radar to assess typical plasma flows established in the ionosphere while the arcs move through the common field-of-view. We show that the optical arcs zonal speed is close to the ExB velocity component. We also investigate the microstructure of plasma flows in the arcs’ vicinity by adding to the large-scale SuperDARN convection patterns data from localized AMISR measurements. For one event, plasma density and magnetometer measurements on the SWARM satellite are added to estimate the location and intensity of the field-aligned currents.
        Speaker: Ms Kateryna Yakymenko (student)
      • 401
        Pre-stellar Cores in the Aquila Rift
        The Herschel Space Observatory, Herschel, is a flagship mission of the European Space Agency operational from 2009-2013 with Canadian participation supported by the Canadian Space Agency. Herschel has enabled ground-breaking astrophysical observations through providing the first unfettered access to the far-infrared region of the electromagnetic spectrum. The Herschel Gould Belt Survey (GBS) has provided a wealth of data to further our understanding of star formation including the provision of data-sets which contains several observations of stellar and pre-stellar cores. The Aquila Rift region, a subset of the Herschel GBS, contains some 77 pre-stellar cores at various stages of development. This work combines photometric data from Herschel (both the Spectral and Photometric Imaging Receiver (SPIRE) and the Photoconductor Array Camera (PACS) instruments) with high resolution heterodyne spectroscopy of CO emission recorded with the instrumentation suite at the James Clerk Maxwell Telescope (JCMT). The high resolution CO emission was observed at the JCMT with the RxA (CO J2-1) and HARP (CO J3-2) receivers. The CO emission spectra allow the determination of the distribution and relative velocity of cold gas in these prestellar cores. The CO results are then compared to photometric results (e.g., dust temperature, emissivity, opacity) obtained through Herschel observations of the same sources. The analysis of these data provide further details towards the understanding and characterization of the evolution of star formation from pre-stellar cores to class 1 protostars and beyond.
        Speaker: Mr Jeremy Scott (Student at the University of Lethbridge)
      • 402
        Early results from the ABOVE radio instrument array
        ABOVE, the Array for Broadband Observations of VLF/ELF Emissions, is a network of radio instruments located across western Canada. The instruments monitor natural and artificial electromagnetic radiation in the frequency range from 200 Hz to 75 kHz. The primary scientific focus is on energetic particle precipitation: we infer precipitation into the atmosphere based on the observed amplitude and phase of remotely transmitted artificial signals, and simultanesouly monitor natural whistler-mode waves (chorus and hiss) that drive the precipitation. Instrument deployment began during the summer of 2014. We report here on the instrument design and the first results.
        Speaker: Christopher Cully (University of Calgary)
      • 403
        A Case Study of Energetic Electron Precipitation Using Ground-Based VLF Radio Data
        We report first results on energetic electron precipitation using the recently deployed ABOVE array. ABOVE is a ground-based array of Very Low Frequency (VLF) radio receivers located across western Canada. With the new instruments, we characterize the properties of electron precipitation during a geomagnetic storm using changes to the phase and amplitude of VLF radio waves from ground based transmitters. We combine ABOVE data with global data from AARDDVARK to investigate electron precipitation on multiple scales.
        Speaker: Eric Davis (University of Calgary)
    • DCMMP Poster Session with beer / Session d'affiches, avec bière DPMCM CCIS Ground Floor PCL lounge

      CCIS Ground Floor PCL lounge

      University of Alberta

      Convener: Mona Berciu (University of British Columbia)
      • 404
        Optomechanics with a Twist
        Torsional resonators are an effective platform to study various material and optical properties. Current advances in nanofabrication techniques allow miniaturization of these torsional oscillators down to micron scale devices but they are often limited by their detection methods. Using a high quality optical resonator ($Q > 10^5$) coupled with a mechanical oscillator, which are the basis of cavity optomechanic, we can enhance torque and angular displacement sensitivities while significantly reducing the effective mass in the order of $\sim$ pg. We have already demonstrated, for the first time, an optomechanical torsion device with torque sensitivities as low as 4 $\times$ 10$^{-20}$Nm/${\sqrt{\textrm{Hz}}}$ and angular sensitivity of 4 nrad/${\sqrt{\textrm{Hz}}}$. We are currently working on improving the design by maximizing the optomechanical coupling coefficient, $G$, which will be an important parameter in cryogenic temperatures where the thermally driven motion will be minimized at $\sim$ mK temperatures. We highlight our progress towards low temperature optomechanics with torsion paddles to improve the coupling rate in $\sim$ GHz/nm range. With our finest dilution refrigerator, upgraded to accommodate optomechanical systems, we hope to explore quantum regimes to study spin-mechanics coupled systems as well as mesoscopic properties of superconductors.
        Speaker: Paul Kim (University of Alberta)
      • 405
        Photonic actuation and detection of higher order modes in nanomechanical resonators
        All-optical actuation and detection of nanomechanical devices has emerged as a promising transduction technique with high displacement sensitivity1-3. However, symmetric mechanical modes are difficult to detect with integrated photonics because the symmetry causes a zero effective index shift. Detection of higher order modes, including symmetric modes, is desirable for sensing applications since higher order modes provide additional information about analyte mass and position4. We demonstrate optical transduction of higher order mechanical modes, including even modes, in nano-optomechanical doubly clamped beams. Doubly clamped beams are fabricated with a step in the underlying substrate to cause a non-zero effective index change. A theoretical model of the optical transduction responsivity is developed to improve our understanding of the system. The thermomechanical noise floor of the first through third modes is observed. With an optical driving force, we measure the first through fifth mechanical modes. The displacement sensitivities of the first through third modes are 170 fm/Hz1/2, 153 fm/Hz1/2, and 140 fm/Hz1/2. The trend of improved sensitivity with increasing mode number is verified by our theoretical model. The increased sensitivity of higher order modes is an important result for future sensing experiments. (1) T. J. Kippenberg, K. J. Vahala. Science **2008**, 321, 1172–1176. (2) M. Eichenfield, J. Chan, R. M. Camacho, K. J. Vahala, O. Painter. Nature **2009**, 462, 78–82. (3) M. Li, W. H. P. Pernice, C. Xiong, T. Baehr-Jones, M. Hochberg, H. X. Tang. Nature **2008**, 456, 480–484. (4) M. S. Hanay, S. Kelber, A. K. Naik, D. Chi, S. Hentz, E. C. Bullard, E. Colinet, L. Duraffourg, M. L. Roukes. Nat. Nanotechnol. **2012**, 7, 602–608.
        Speaker: J. N. Westwood-Bachman (University of Alberta, National Institute for Nanotechnology)
      • 406
        Coupling THz Pulses to a Scanning Tunneling Microscope
        Probing ultrafast processes over subpicosecond and picosecond time scales provides fundamental insight into the nature of materials. We have experimentally demonstrated terahertz (THz)-pulse-induced tunneling in a scanning tunneling microscope (THz-STM) to image surfaces with simultaneous nanometer spatial resolution and subpicosecond time resolution.However, the exact mechanism by which THz radiation couples to the scanning probe tip of the STM is not completely understood. THz radiation can excite surface plasmon polaritons (SPPs), which propagate as Sommerfeld waves along a metal wire waveguide with low loss and dispersion. For metal wires with a sharp taper, electromagnetic fields are enhanced due to the localization of SPPs at the apex. Here, we simulate THz-pulse-coupling to a STM tip in THz-STM as a near-field THz microscopy technique. COMSOL Multiphysics is used to set up finite-element time-domain simulations for the coupling of THz pulses to an STM tip in a modeled THz-STM geometry. Simulation results show THz scattering, waveguide propagation and near-field enhancement. The simulations provide insight into the nature of THz pulse coupling to the scanning probe tip in THz-STM, which may lead to improvements in coupling efficiency, and help in modeling the THz modulation of the STM junction bias and the resulting THz-induced tunneling emission.
        Speaker: Peter Nguyen (University of Alberta)
        Slides
      • 407
        Ultrafast All-Optical Switching in Semiconductor Nanoparticles
        Ultrafast all-optical switching offers great benefit to communication technologies, as all-optical logic operations can be performed at tremendous (terabit-per-second) data rates. Semiconductors are an obvious choice to perform such switching, given their strong optical nonlinearity, but standard bulk semiconductors suffer from relatively slow recombination—often with nanosecond or microsecond charge-carrier lifetimes. These are unfavorable material characteristics aspects for ultrafast all-optical switching, as the slow recovery impedes the ultimate data rate. To address the demands of ultrafast all-optical switching, the work put forward here investigates semiconductor nanoparticles as a material for ultrafast photoexcitation and recombination. Composite materials comprised of semiconductor nanoparticles in a polymer host are fabricated and investigated. Semiconductor nanoparticles of Si and SiC are employed, with average particle diameters of 20 nm and 50 nm, respectively. An ultrafast pulsed laser system, with 100 fs optical pulses, is used to carry out pump-probe spectroscopy on these materials. For Si, it is found that the photoexcited charge-carriers undergo recombination with a lifetime of 12 ps (being on the order of one thousand times shorter than the 20 ns bulk lifetime). For SiC, it is found that the photoexcited charge-carriers undergo recombination with a lifetime of 2.5 ps (being on the order of one million times shorter than the 22 µs bulk lifetime). A theoretical model is developed to interpret the experimental findings. The model characterizes the ultrafast charge-carrier dynamics within the nanoparticles according to diffusion and recombination processes. It is found that the increased surface-to-volume ratio of the nanoparticles promotes surface recombination, over a picosecond timescale, and this leads to the observed short charge-carrier lifetimes. The enhanced recovery times seen in these materials can be beneficial for future implementations of ultrafast all-optical switching.
        Speaker: Jeff Krupa (University of British Columbia)
      • 408
        GC-MS to GC-NOMS: A step towards portable analysis
        The Gas Chromatography (GC) – Mass Spectrometer (MS) system is the industry benchmark in research and chemical analysis. However given that MS systems are large and complicated instrumentation, chemical analyses have a long turnaround time. In this regard, portable GCs have carved a market niche but they have poor sensitivities. Recent demonstrations with Nanooptomechanical (NOMS) resonators at atmospheric pressure have proven that these kind of sensors have the breakthrough potential to improve the sensitivity of portable GCs. In this regard we have built an experimental rig to integrate the GC system with our NOMS device. The goal of this study is two-fold. One will be to replace the GC sensor with NOMS devices, integrate with the portable GCs for better sensitivity, and ultimately match the analytical power of conventional GC-MS. The other will be to demonstrate the NOMS sensing capabilities for next generation genomic applications like personalized medicine. In this regard, we have designed and developed a free space interferometry system. The probe laser is coupled in and out of the photonic waveguide using grating couplers. Using the evanescent field of the waveguide, the shift in resonant frequency of the nanoscale resonators is recorded using lock in amplifier. Here we have tracked the response of both the ring resonators using the photodetector output and the nanomechanical resonator using the phase locked loop (PLL). GC peak sensing can be done with either or both of the mechanical and the photonic sensors. During the initial testing with analyte standards we observed the ring resonator to respond faster than the nanomechanical resonator on par with the GCs flame ionization (FID) detector. We were also able to capture the analyte peaks effectively with the sensitivity of the resonators to be about 77 zg/Hz.
        Speaker: Dr Anandram Venkatasubramanian (Post Doctoral research fellow)
        Poster
      • 409
        Poor Q-factor? - no problem: nano-optomechanical mass sensing in ambient conditions
        It has been demonstrated that optimum dynamic range (DR) and high quality factor (Q) of NEMS resonators provides unprecedented mass sensitivity [1]. The mass sensitivity and frequency stability of these devices are limited by their thermomechanical (TM) noise. TM noise goes down with Q as pressure increases, at the same time enhanced critical amplitude leads to a higher DR value with better sensitivity. However, detecting TM noise signal at ambient condition is always challenging. Optomechanical transduction successfully resolved this challenge with high displacement sensitivity and high bandwidth of NEMS devices [2]. Previously we have demonstrated the supremacy of our optical racetrack resonator transduction scheme in detecting TM noise signal [3]. Taking advantage of this measurement protocol we have found zeptogram level mass sensitivity at atmospheric pressure for a double clamped beam. This is similar to the sensitivity in high vacuum, even though Q-factor drops 300 fold from vacuum to ambient pressure. These intriguing experimental results challenge assumptions about fundamental limits of mass sensitivity of NOMS sensors and open the door for ultrasensitivity in ambient conditions. 1. K. L. Ekinci, Y. T. Tang and M.L. Roukes, “Ultimate limits to inertial mass sensing based upon nanoelectromechanical systems.”, J. Appl. Phys. Vol. 95. No.5, March 2004. 2. M. Li, W. H. P. Pernice, C. Xiong, T. Baehr-Jones, M. Hochberg, and H. X. Tang, “Harnessing optical forces in integrated photonic circuits.” Nature, Vol.456, pp.480-4, Nov.2008. 3. V. T. K. Saur, Z. Diao, M. R. Freeman, and W. K. Hiebert, “ Optical racetrack resonator transduction of nanomechanical cantilevers.” Nanotechnology, Vo.25, 05522, 2014.
        Speaker: Mr S. K. Roy (Department of Physics, University of Alberta and National Institute for Nanotechnology (NINT), Canada.)
      • 410
        Modeling dome microcavities in COMSOL
        Dome microcavities are on-chip optomechanical devices formed by two quarter-wave Bragg stacks of silicon on silica. One of these mirrors is buckled away from the chip and is allowed to vibrate. These vibrations are thermally driven and can be detected using shifts in the optical resonances of the cavity. We use COMSOL Multiphysics software model to the coupling between the optical and mechanical modes of the device and compare these simulations to experimental values to confirm the accuracy of the model. Utilizing the model as a base-case, the optomechanical properties of future devices can be predicted and optimized.
        Speaker: Hugh Ramp (University of Alberta)
      • 411
        Thermophysical Properties of Heavy Water and Pertinent Calculations
        Heavy water consists of molecules of deuterium oxide. Heavy water is used in applications that require the special nuclear properties of a deuterium (hydrogen-2) atom. These applications have included solar-neutrino detectors and nuclear-fission reactors. The thermophysical properties of heavy water have been considered in such applications. Since the mass of a deuterium-oxide molecule is about 11% greater than the mass of a typical hydrogen-oxide molecule, the thermophysical properties of heavy water differ significantly from the thermophysical properties of ordinary water ("light water"). The present study involved two fluids: heavy water and ordinary water. The liquid-vapour coexistence curves of the two fluids were compared. The accuracy of empirical formulations and theoretical expressions for thermophysical properties was examined. Thermophysical properties, such as specific volume, specific heat capacities, thermal conductivity and viscosity, were studied. Calculations for heavy-water systems ought to be based on information for heavy water.
        Speaker: Dr Robert L. Varty (Consultant in Engineering Science)
      • 412
        Deuterium NMR and Rheology of Microgel Colloids at Ambient and High Pressure
        Because they can exhibit a collapse transition at high temperatures or pressures, microgel colloids are of interest because of their potential for applications in areas like drug delivery and chemical separation that involve the uptake, encapsulation and release of small or biological molecules. In this work, we have used deuterium NMR and dynamic light scattering (DLS) to relate the microscopic dynamics of cross-linked poly-N-isopropylacrylamide (p-NIPAM) chains, in microgel colloids, to the observed changes in particle size with temperature and pressure. Microgels have been synthesized with deuteron labels on the NIPAM side chains (d7-NIPAM) or on the NIPAM backbone (d3-NIPAM). DLS observations obtained while heating suspensions of these materials have shown that particles in suspensions of both undergo a collapse transition, around $35^\circ$C, at which the radius of gyration is roughly halved. ${}^2$H-NMR spectra of the d7-NIPAM microgel can be modeled as a superposition of doublets having a smooth distribution of small quadrupole splittings. This is interpreted as reflecting the combined effects of methyl rotation, sidechain reorientation, and polymer backbone motions. At the collapse transition, the distribution of splittings required to simulate the observed spectra extends to larger splittings, presumably reflecting the more constrained backbone motion in the collapsed phase. Comparison with spectra being obtained using the backbone-deuterated microgel material will be used to more directly characterize changes in the polymer backbone motion at the transition. Supported by NSERC.
        Speaker: Suhad SBEIH (Memorial University of Newfoundland)
      • 413
        Adsorption of thiophene-based molecules at passivated silicon surfaces
        Molecular self-assembly of organic layers at surfaces is a powerful method to achieve the design and fabrication of nanostructures. The self-assembly of large-scale 2-d supramolecular networks at silicon surfaces is a particular challenge due to the large number of dangling bonds which suppress the diffusivity of adsorbed molecules and even break the molecules apart via the formation of Si-C bonds. An essential requirement for the fabrication of high quality organic layers on silicon is passivation of the dangling bonds. We have studied the adsorption of brominated π conjugated tetrathienoanthracene molecules (TBTTA) onto the passivated Si(111)-B surface at room temperature. Thiophene based molecules like TBTTA are of considerable interest in organic semiconductor research due to their efficient conjugation and the chemical stability [1]. The Si(111)-B surface is prepared by annealing highly boron doped silicon wafers under ultrahigh vacuum for extended periods. Annealing leads to boron segregation at the surface. At a maximum boron surface atom concentration of 1/3 of a monolayer (ML) the sample exhibits a √3 × √3R30° reconstruction. This surface has no Si dangling bonds and therefore should provide a high mobility surface for TBTTA adsorption. We will discuss our recent results on the boron surface and compare with our earlier work on the passivated Si(111) √3 × √3-Ag surface. On the silver surface TBTTA molecules are highly mobile and form large 2-d supramolecular domains with a unit cell dominated by relatively weak intermolecular interactions. 1. R. Gutzler et al., Nanoscale 6, 2660-2668 (2014).
        Speaker: Renjie Liu (Lakehead University)
        1
      • 414
        Dielectric spectroscopy of polyvinyl alcohol cryogels
        Gels based on polyvinyl alcohol (PVA) can be formed by repeated freezing and thawing of a solution of the polymer. PVA cryogels have applications as biomaterials, including artificial tissue and drug delivery systems. The mechanical and electrical properties of polymeric materials can be changed significantly by adding a small amount of nanometer-sized particles. In this work, the dielectric properties of PVA solutions and gels were studied in the frequency range from 10 $mu$Hz to 1 MHz as a function of temperature, using a dielectric spectrometer. Comparison of the dielectric constant of a PVA solution to that of water indicates that --OH groups on the polymer make a large contribution to the dielectric response above 273 K. The real and imaginary parts of the dielectric constant $\varepsilon$ decrease during the cooling phase of a freeze-thaw cycle due to a reduction in the mobility of the dipoles and do not completely recover on thawing. Similarly, a relaxation peak in $\varepsilon^\prime$ for the PVA gel moves to lower frequency as the temperature is decreased due to a slowing of the relaxation process. We interpret these results in terms of the structural changes that take place within the PVA gel in the process of gel formation. We also investigate the effect of incorporating a small concentration of multi-walled carbon nanotubes into the cryogels.
        Speaker: John de Bruyn (Western University)
      • 415
        Granular assemblies: a sandbox of nonlinear physics phenomena
        Granular materials play a major role in our daily lives and are vital to the function of a diverse array of industries, from agriculture to mining to pharmaceutical manufacturing. Understanding the dynamics of granular media is of fundamental importance to the study of matter in general, and beyond being intimately connected to a variety of natural geophysical phenomena, knowledge of the behaviour of these systems has many potential implications to industry. For example, granular systems are useful in applications related to shock absorption and vibration reduction primarily because they are capable of dissipating mechanical energy through inelastic collisions and friction between the grains. As energy is transferred between grains they deform slightly, and the contact potential arising from the elastic deformation of grains is given by the nonlinear Hertz law. The discrete nature of these systems in combination with the nonlinear contact interaction between grains leads to complex collective behaviour, providing a sandbox of interesting physics phenomena. Investigating granular chains gives insight into this complex behaviour, and also provides the stepping stone required to comprehend the dynamic behaviour of higher-dimensional analogues. Our work focuses on the dynamics and statistical mechanics of granular chains and, in particular, on how these systems can be exploited to locally trap vibrational energy. Using particle dynamics simulations, we investigate how solitary wave propagation in these systems is affected by material properties, and how introducing inertial mismatches affects the reflection of solitary waves at boundaries. We also look into how material properties affect energy localization and equipartitioning processes in these systems.
        Speaker: Michelle Przedborski (Brock University)
        Poster
      • 416
        Anisotropic Bragg mirror made from one single material used for polarized laser emission from a Yb-doped YAG ceramic
        We propose a novel anisotropic Bragg mirror made of alternating high- and low-index layers of one single material, of which the refractive index is controlled by changing the angle between the sample normal and the average direction of the evaporated material during the deposition process, a technique called glancing angle deposition or GLAD, which affects the nanoporosity and hence the refractive index of the material [1-3]. By changing the incidence angle of the deposition, we could change the refractive index of a tungsten trioxide WO3 by as much as 0.3 and obtain a birefringence, Δn, as high as 0.08, as measured with ellipsometry. Next, we could exploit the anisotropy of the layers to fabricate linear polarizers which, when applied as output coupler to a Yb3+-doped YAG ceramic material, could produce linearly polarized laser output with high extinction ratio. This fabrication technique can be used to deposit such coating directly on the facets of a cheap ceramic isotropic laser material and thereby produce a monolithic linearly polarized laser microchip. It allows one to avoid the costly steps of etching regular linear ridges into an isotropic Bragg mirror to form a resonant grating mirror, as previously proposed in Ref. [4]. The fabrication technique, the optical properties of othe produced coatings and the properties of the laser output obtained by placing such coating on a laser material will be presented. [1] G. Beydaghyan, K. Kaminska, T.Brown, K.Robbie, Enhanced birefringence in vacuum evaporated silicon thin films, Appl. Opt., 43(28), 5343-5349 (2004). [2] K. Robbie, G .Beydaghyan, T.Brown, C.Dean, J.Adams, C.Buzea, Ultrahigh vaccum glancing angle deposition system from thin films with controlled 3-D nanostructure, Rev. Sci. Instrum, 75, 1089-1097 (2004). [3] K.M.A. Sobahan, Y.Jun Park, J.J.Kim, Y.S.Shin, J.B.Kim, C.K.Hwangbo, Nanostructured optical thin films fabricated by oblique angle deposition, IOPscience, 1, 045005 (2011). [4] J.-F. Bisson, O. Parriaux, J.C.Pommier, S. Tonchev, K.Ueda, A polarization-stabilized microchip laser using a resonant grating mirror, Appl. Phys. B Lasers and Optics, 85, 519-524, (2006).
        Speaker: Jean-François Bisson (Université de Moncton)
    • DIAP Poster Session with beer / Session d'affiches, avec bière DPIA CCIS Ground Floor PCL lounge

      CCIS Ground Floor PCL lounge

      University of Alberta

      Convener: René Roy (Université Laval)
      • 417
        Water and Defect Detection Beneath Rubber Using Terahertz Reflection Tomography
        Royal Canadian Navy VICTORIA Class submarines must operate with enhanced stealth using rubber acoustic tiles over their steel hulls to provide SONAR cloaking and absorb emanating noise. These tiles, as well as a connective grouting compound, form an opaque covering of virtually the entire hull surface. In evaluating the integrity of the hull as a pressure vessel it is of paramount importance to discern states of deterioration and corrosion of the underlying steel, in addition to water seepage and delamination within the tiles and grouting interfaces themselves. With a rubber transmission window at approximately 80 GHz, Terahertz (THz) sensing methods have shown promise for probing these slab-like structures in laboratory. In practice, non-destructive examination must be done from the outside surface of the hull with the radiation reflecting off of the metal subsurface, thus passing through the strongly absorbing cloaking layers twice. Working in conjunction with Defense Research and Development Canada (DRDC) towards a practical hull inspection technology for VICTORIA Class submarines, we have investigated the potential applications of THz reflection tomography to water, corrosion, and delamination detection beneath opaque rubber media. We have investigated 1” thick rubber tile analogous to those used on the submarines using a Brewster-angle reflection terahertz time-domain spectroscopy apparatus.
        Speaker: Mr Patrick Kilcullen (University of Northern British Columbia)
    • DIMP Poster Session with beer / Session d'affiches, avec bière DPIM CCIS Ground Floor PCL lounge

      CCIS Ground Floor PCL lounge

      University of Alberta

      Convener: Kirk Michaelian (Natural Resources Canada)
      • 418
        Focus study to measure phase effects of a bent Laue beam expander
        At the Canadian Light Source (CLS) in Canada, the BioMedical Imaging and Therapy (BMIT) bend magnet (BMIT-BM) beamlines and insertion device (BMIT-ID) have been very successful in their mission to image biological tissue and conduct live animal imaging studies. However, since their inception, they’ve been limited by the vertical beam size. This poses limitations for imaging modalities such as micro-computed tomography and dynamic phase imaging, techniques which are necessary to remain at the cutting edge of biomedical imaging research. In order to observe edge-enhancement refraction effects, the source must be angularly small. When an X-ray beam is diffracted through a Bent Laue crystal, the apparent angular source size can be adversely affected if the single-ray focus does not coincide with the geometric focus. In order to preserve the beam’s transverse coherence, these two focal points must coincide in what is referred as the “magic condition.” We previously reported results of a vertical beam expansion up to 7.7x. However, these attempts resulted in significant degradation of the beam’s phase characteristics in the vertical direction (corresponding to horizontal edges in the object). We approached this problem from two angles. On the Physics side, we derived a better approximation for the polychromatic focal length and carefully merged it with the well-established geometric focus equation. On the Engineering side, we developed a bending frame that more carefully controls the bend radius of the crystal. The result of this effort is a great improvement in the coherence of the expanded beam, enabling techniques such as dynamic phase imaging at the BMIT beamlines. In this work, results are presented of a focus study around the optimal Bragg angle for a (5,1,1)-type silicon wafer using a (3,1,1)-type reflection with asymmetry angle χ=3.33°. Images of tungsten carbide blocks (knife edge) and Lucite rods (phase object) were analysed to determine the width of the edge or phase fringe, measured in pixels, as a function of the Bragg angle. In summary, our findings were that the “magic condition” is somewhat soft and robust against deviations from the optimal energy, allowing some freedom in energy choice to suit other requirements from imaging experiments, such as specific K-edges of contrast agents or absorption characteristics of the sample.
        Speaker: Mercedes Martinson (University of Saskatchewan)
      • 419
        Development of a Vibrating Wire Rheometer
        Vibrating wire devices have been used in the past to determine the viscosity of Newtonian fluids. We are investigating the use of a vibrating wire device to measure the viscous and elastic moduli of non-Newtonian fluids. Our device consists of a small diameter tungsten wire under tension and immersed in a fluid. When a magnetic field is applied and an alternating current is passed through the wire, it vibrates at the driving frequency. The resonance frequency of the wire can be tuned by varying its length and the applied tension, giving an accessible frequency range of 600 - 6800 Hz. A dual phase lock-in amplifier is used to measure the in-phase and out-of-phase components of the voltage across the wire as a function of frequency. The Navier-Stokes equations can be solved for this system and an analytic expression can be derived relating the voltage across the wire to the physical parameters of the system, including viscosity. The viscosity of a fluid can be determined by fitting the measured voltage to this function. In this poster we discuss the design and operation of our vibrating wire rheometer and present results for a variety of Newtonian fluids and polymer solutions.
        Speaker: Prof. John de Bruyn (The University of Western Ontario)
      • 420
        Update of the imaging capabilities of the biomedical imaging and therapy facility at the Canadian Light Source
        The BioMedical Imaging and Therapy (BMIT) facility provides synchrotron-specific imaging and radiation therapy capabilities [1-5]. There are two separate end-stations used for experiments: the Bending Magnet (BM) 05B1-1 beamline [3] and the Insertion Device (ID) 05ID-2 beamline [4-5]. Core research programs include human and animal reproduction, cancer imaging and therapy, spinal cord injury and repair, cardiovascular and lung imaging and disease, bone and cartilage growth and deterioration, mammography, developmental biology, gene expression research as well as the introduction of new imaging methods. There has been an active user program on the 05B1-1 beamline for the last four years and this is now expanding with the opening of 05ID-2 to higher energies (up to 120 keV) and a higher capacity positioning system (up to 450 kg). The CT program in particular has grown rapidly and is expected to grow not only in terms of the number of proposals but also in terms of greater complexity, desire for greater speed with higher resolution and the imaging of live animals. CT scans can range from imaging of a piglet with 200 µm resolution to imaging of bone samples with micron resolution. In this poster we update the capabilities of the BMIT facility and describe recent developments of the imaging modalities available for users. Examples of imaging techniques developed at BMIT include: K-edge subtraction imaging (KES and spectral-KES), phase contrast imaging (PCI) and Diffraction Enhanced Imaging (DEI, also known as ABI) both in projection and CT modes. Looking forward, BMIT is adding new capabilities such as a larger vertical beam, faster detectors and access to higher energies. REFERENCES 1. Chapman LD, (2007) CLSI Doc. No. 26.2.1.1 Rev. 0.A 2. Chapman LD, (2006) CLSI Doc. No. 26.2.1.2 Rev. 0 3. Wysokinski TW et al. (2007) NIM A 582:73-76 4. Wysokinski TW et al. (2013) J. Phys: Conf Ser 425: 07 5. Wysokinski TW et al. (2015) NIM A 775:1-4.
        Speaker: M. Adam Webb (Canadian Light Source)
        Poster
      • 421
        The Brockhouse X-ray Diffraction and Scattering Sector at the Canadian Light Source
        The status of the construction of the Brockhouse X-Ray Diffraction and Scattering Sector, at the Canadian Light Source, will be discussed. The sector will be in operation in 2017 and will support a diverse, active and successful community of Canadian and international materials scientists. The instrumentation will meet their diverse needs by providing excellent performance over a broad x-ray energy range from 5 to 94 keV. To achieve this, three beamlines will be sourced by two complementary insertion devices: a small gap undulator and a small gap permanent magnet wiggler. The undulator will source a high brilliance, low energy beamline (5-21 keV) that will be dedicated to diffraction, resonant and inelastic scattering and SAXS/WAXS experiments. The divergent x-ray beam produced by the wiggler will be divided by two side-bounce monochromators into two independent diffraction beamlines. One of them will be a low energy beamline (7-22 keV) and will be used for high-resolution powder diffraction, microcrystal crystallography and reciprocal space mapping. The second wiggler beamline will be a high energy one (20-94 keV) and will be dedicated to diffraction and scattering under extreme conditions and high-resolution pair distribution function measurements. Details of the performance and capabilities of each experimental end-station will be shown.
        Speaker: Ariel Gomez (Canadian Light Source)
      • 422
        Improving sensitivities and detection limits of fluorescence-based microcavity refractometric sensors
        Refractometric sensors can be used to detect small changes in refractive index (RI) of an analyte fluid. In microfluidics, they can be used to measure temperature or chemical changes in a miniscule analyte volume. Refractometric sensors can be extended into the biosensing domain via chemical functionalization of the sensor surface. My project goal is to find ways to improve the sensitivities and detection limits of the fluorescence-based microcavity refractive index sensors. In a spherical or cylindrical dielectric with a circular cross section, light can propagate around the circumference by total internal reflection, forming the so-called whispering gallery mode (WGM) resonances. I work primarily with optical fiber (d = 125 $\mu$m ) and quartz micro-capillary (d = 50 $\mu$m ) sensors that demonstrate WGM resonances. These structures are coated with a thin film (up to 1 $\mu$m) consisting of a silica matrix embedded with silicon quantum dots. Under blue laser light, these have a broad red fluorescence which overlaps with the WGM spectrum of the sensor. Since the film has a higher RI than the glass fiber or capillary, fluorescent WGMs are mostly confined within the film but their profiles extend slightly into the inner (capillary) or outer (optical fiber) medium. Spectra of the quantum dot fluorescence then feature regular sharp peaks associated with the cylindrical dielectric fiber or capillary resonances in that particular medium. By continuously collecting fluorescence WGM spectra and monitoring the peak positions, I can make sensorgrams (change in RI over time) as the sensor is exposed to different fluids. These devices have sensitivities of tens of nanometers per RIU (refractive index unit) and modest detection limits on the order of $10^{-4}$ RIU. I will show how to obtain a threefold improvement to our signal-to-noise ratio and thus our experimental detection limit by controlling for environmental factors and by using data processing methods. I’ll also discuss two additional fabrication methods which may increase the sensitivities and thereby further decrease the detection limits of these devices.
        Speaker: Rose (Deborah) Chung (Department of Physics, University of Alberta)
        Poster
    • DMBP Poster session, with beer / Session d'affiches DPMB, avec bière CCIS Ground Floor PCL lounge

      CCIS Ground Floor PCL lounge

      University of Alberta

      Convener: Maikel Rheinstadter (McMaster University)
      • 423
        Massively parallel genomic analysis using tunable nanoscale confinement
        Linearly extending long DNA molecules in sub-50 nm nanochannels for genomic analysis, while retaining their structural integrity, is a major technological challenge. We employ ``Convex Lens-induced Confinement'' (CLiC) microscopy to gently load DNA into nanogrooves from above, overcoming the limitations of side-loading techniques used in direct-bonded nanofluidic devices. In the CLiC technique, the curved surface of a convex lens is used to deform a flexible coverslip above a glass substrate, creating a nanoscale gap that can be tuned during an experiment to load and confine molecules into nanoscale features embedded in the bottom substrate. Since DNA molecules are loaded into the embedded nanotopography from above, CLiC eliminates the need for the high pressures or electric fields required to load DNA into direct-bonded nanofluidic devices. To demonstrate the versatility of CLiC, we confine DNA to a variety of nanostructures (linear, circular, gridded patterns of nano grooves), demonstrating DNA nanochannel-based stretching and denaturation mapping (Berard et al, PNAS 2014). We have successfully extended DNA in as small as 27-nm channels, achieving high stretching (90 percent) that is in good agreement with Odijk deflection theory and demonstrating mapping of genomic features using denaturation analysis. Additionally, we have recently demonstrated single-fluorophore resolution and resolved nick-labeled DNA in these devices, establishing compatibility with a suite of DNA mapping methods in the biotechnology sector.
        Speaker: Marjan Shayegan
      • 424
        Single-Molecule Microscopy System for Tunable Nanoscale Confinement
        We present the design and construction of a versatile, open-frame inverted microscope system for wide-field fluorescence and single molecule imaging. The microscope chassis and modular design allow for customization, expansion, and experimental flexibility. We present two components that are included with the microscope which extend its basic capabilities and together create a powerful microscopy system. The first is a piezoelectric controlled Convex Lens-induced Confinement (CLiC) device that provides the system with single-molecule imaging capabilities, and the ability to manipulate molecules at the nanoscale. The CLiC device creates a precise sample-chamber gap that can be adjusted during an experiment to confine molecules or align them within embedded nanostructures. Additionally, a two-color imaging system provides the option of imaging multiple molecular species simultaneously. The flexibility of this microscopy system with its open-framed chassis combined with accessible single-molecule, multi-species imaging technology supports a wide range of new measurements in the health, nanotechnology and materials science research sectors.
        Speaker: Mr Adriel Arsenault (McGill University)
    • DNP Poster Session with beer / Session d'affiches, avec bière DPN CCIS Ground Floor PCL lounge

      CCIS Ground Floor PCL lounge

      University of Alberta

      Convener: Zisis Papandreou (University of Regina)
      • 425
        Evolution of Single Particle Structure in Exotic Strontium Isotopes
        Nuclei near the magic numbers of protons and neutrons are observed to have a spherical shape for the low lying states. Nuclei between magic numbers, where the binding energy tends to be lower, are often observed to show deformation in low lying states. These deformations are perceived to have either a prolate or oblate nature. States within a nucleus that have different shapes that are close in energy are colloquially referred to as shape coexisting. A dramatic occurrence of shape coexisting states is observed in nuclei in the vicinity of Z=40, N=60 , which is the subject of substantial current experimental and theoretical effort. An important aspect in this context is the evolution of single particle structure for N $<$ 60 leading up to the shape transition region, which can be calculated with modern large scale shell model calculations using a $^{78}$Ni core or Beyond Mean Field Models. One-neutron transfer reactions are a proven tool to study single-particle energies as well as occupation numbers. Here we report on the study of the single-particle structure in $^{95,96,97}$Sr via (d,p) one-neutron transfer reactions in inverse kinematics. The experiments presented were performed in the ISAC facility using the TIGRESS gamma-ray spectrometer in conjunction with the SHARC charged-particle detector . Highly charged beams of $^{94,95,96}$Sr, produced in the ISAC UCx target and charge-bred by an ECR source were accelerated to 5.5 MeV/A in the superconducting ISAC-II linac before delivery to the experimental station. Other than their clear scientific value, these measurements were the first high mass (A $>$ 30) post-accelerated radioactive beam experiments performed at TRIUMF. A thorough analysis of single particle states will improve our understanding of the onset of these unique structures, encouraging the ongoing theoretical discussions. Initial results discussed in the context of the evolution of single-particle structure will be presented.
        Speaker: Steffen Cruz
      • 426
        Low-Light Photosensor Applications in Plant Imaging & Personal Radiation Detection
        Silicon photomultipliers - also known as Multi-pixel Photon Counters (MPPCs) - are a type of photodetector that have shown great potential for many applications such as nuclear and particle physics, nuclear medicine, biophotonics, outer space, military, atmospheric or automotive distance control lidar, radioactivity detection and monitoring, and nuclear hazard/threat detection. Out group has embarked on the application of these devices to two areas: plant imaging and personal radiation detectors for first responders and general consumers.
        Speaker: Jamie Sanchez-Fortun Stoker (University of Regina)
    • DPE Poster Session with beer / Session d'affiches avec bière DPE CCIS Ground Floor PCL lounge

      CCIS Ground Floor PCL lounge

      University of Alberta

      Convener: Calvin Kalman (Concordia University)
      • 427
        37 Years of High School Physics Olympics Competitions at the University of British Columbia
        The Physics Olympics is an annual high school physics competition held at the University of British Columbia in Vancouver. This year, more than 400 students on 56 teams, with at least one teacher/coach per team, came from all over British Columbia to participate in the 37th Annual Physics Olympics. The competition consists of six hands-on events, of which two are pre-built by the students in the month before the competition. In recent years, a professional development workshop and networking opportunities have been offered to the physics teachers/coaches. We believe it is one of the largest annual physics high school outreach events in Canada. More than 10 faculty members and more than 60 Physics and Astronomy undergraduate and graduate students are involved each year in designing, prototyping and testing events and apparatus for the Olympic events and helping run the event on the big competition day.
        Speakers: Janis McKenna (University of British Columbia), Marina Milner-Bolotin (The University of British Columbia)
    • DPP Poster Session with beer / Session d'affiches, avec bière DPP CCIS Ground Floor PCL lounge

      CCIS Ground Floor PCL lounge

      University of Alberta

      Convener: Chijin Xiao (Univ. of Saskatchewan)
      • 428
        Measurement of High Magnetic Fields in Laser Produced Plasmas
        Many high intensity laser applications can generate large magnetic fields up to the level of 100’s of Tesla. In particular, the application of circularly polarized [1] or orbital angular mode (OAM) laser beams [2] can be used to generate such large fields using the inverse Faraday Effect (IFE). These fields can play an important role in the generation and guiding of electrons in laser plasma interaction process. Traditional techniques such as the Faraday rotation of the polarization of a probe beam can be applied to measure fields in the 10’s to 100’s of Tesla range [3]. An alternative technique is to observe the Zeeman splitting of emission lines where the spin orbital angular momentum shifts the energy levels of a set of initially degenerate emission lines [4, 5]. We are interested in exploring techniques for generating fields on the order of 100’s of Tesla and are currently investigating techniques for measuring magnetic fields in plasmas. Emissions lines are being explored as potential candidates for Zeeman splitting measurements of magnetic fields. Faraday rotation is also being investigated as an alternative technique. Hybrid Particle in Cell (Hybrid-PIC) code calculations of high intensity interactions will be carried out to predict the expected levels of magnetic field which would be generated under various interaction conditions. Progress on characterization of these measurement techniques and modeling of the magnetic field generation process will be presented. **References:** 1. Z. Najmudin et al., Phys. Rev. Lett. 87,215004 (2001) 2. S. Ali, J. R. Davies and J. T. Mendonca, 37th EPS Conference on Plasma Physics, P5.211 (2010) 3. E. A. McLean, J.A. Stamper et al., Phys. Fluids 27(5), 1327(1984) 4. F. C. Jahoda, F. L. Ribe and G. A. Sawyer, Physical Review 131 (1), 24 (1963) 5. N. J. Peacock and B. A. Norton, Physical Review A 11 (6), 2142, (1974)
        Speaker: Ms Fatema Liza (University fo Alberta)
        1
      • 429
        Intense, double pulse irradiation of targets for MeV proton acceleration
        The efficient generation of MeV proton beams using lasers is an area of interest due to its potential applications, ranging from radiotherapy to the fast ignition concept for inertial confinement fusion. Various efficiency-enhancing schemes have been put forward, including using ultra-clean pulses with nm thick foils, and structured targets such as hemispheres to enhance fields. One method, temporally separating sub-picosecond, ultra-intense pulses, has been shown to increase the conversion efficiency of laser energy to MeV protons[1]. Using this scheme, we performed an experimental characterization of proton acceleration at the Titan laser at Lawrence Livermore National Laboratory. Thin (um-scale) foil targets were irradiated by two 700 fs, 1ω pulses separated by 1 to 5 ps; the total beam energy was 100 J, with 5-20% of the total energy contained within the first pulse. Radiochromic film stacks and magnetic spectrometers were used to measure the proton beam spectrum and conversion efficiency. The effect on electron generation, which is an intermediate stage of proton acceleration, was measured using Kα x-ray emission from buried Cu tracer layers, while specular light diagnostics indicated the laser coupling efficiency into the target. A substantial increase was not observed, likely due to a moderating effect of laser prepulse energy, which was on the order of 10 mJ. These results will be presented and compared to particle-in-cell (PIC) simulations. *Work by LLNL was performed under the auspices of U.S. DOE under contract DE- AC52-07NA27344. [1] Brenner et al., Appl. Phys. Lett. 104, 081123 (2014).
        Speaker: Shaun Kerr (University of Alberta)
      • 430
        Interferometric characterization of preplasma density for laser created plasmas
        High intensity laser plasma interactions are often affected by the preplasma created by leakage laser light (typically millijoules over nanoseconds) prior to the main high energy laser pulse (typically 100’s of joules). Even small amounts of preplasma can alter the absorption of laser light and creation of high energy electrons and ions in the interaction process. This can have significant effects on the application of such pulses for areas such as Fast Ignition Laser Fusion Energy. In order to correctly model the interaction process it is important to know the plasma density profile accurately prior to the main interaction process. The current study is focussed on characterizing the expected preplasma conditions for experiments carried out at the Titan laser facility at the Lawrence Livermore National Laboratory (LLNL). Interferometric measurements for accurate characterization of the plasma density profile of an aluminum plasma created by nanosecond duration 532nm Nd:YAG laser pulses are carried out using a femtosecond-laser probe pulse (400nm/130fs). The main laser pulse is focussed onto an aluminium rod using f/20 optics producing a 20µm diameter focal spot and the interferometry is carried out using a Mach Zehnder Interferometer. The interferograms are used to determine the evolution of the density profile of the plasma with time over a time scale of 1 to 5 nanoseconds. The results are then compared to 2D hydrodynamic modeling of the plasma expansion and used to determine the equation of state models which best fit the experiment. From these results, we expect that more accurate preplasma density models can be developed and incorporated into the analysis of high intensity laser plasma interaction experiments. The experimental results will be presented and discussed.
        Speaker: Laila Nawsheen Manzoor (University of Alberta)
      • 431
        Optical Pumping Within a Laser-Induced Plasma to Enhance Trace Element Signal Intensity
        In the field of laser-induced breakdown spectroscopy (LIBS), it has been shown that trace elements can typically be detected at the parts per million level. However, to decrease the limit of detection further, there is a need to enhance the relatively small spectral lines of the trace elements. The technique of laser-induced fluorescence (LIF) is one of the best tools for providing this enhancement. A wavelength-tunable optical parametric oscillator (OPO) laser is used on resonance to selectively populate an excited state within the laser-induced plasma. Subsequent spontaneous emission will then be increased relative to the un-pumped plasma allowing smaller concentrations to be detected. This poster will present our efforts to demonstrate LIBS-LIF in a LIBS plasma generated by a 10 ns 1064 nm pulsed laser. Initial studies pumped trace zinc in a brass alloy. Parameters investigated included interpulse timing, OPO laser spot size and pulse energy, background gas environment, and plasma observation timing. This technique will be implemented to improve the measurement of trace zinc in fingernails as well as trace elements in bacterial specimens.
        Speaker: Mr Anthony Piazza (University of Windsor)
        Slides
      • 432
        Terahertz source development for studying Warm Dense Matter and High Energy Density Plasmas
        After decades of being referred to as the terahertz gap, terahertz radiation is now routinely used in spectroscopic and imaging applications. Further advancement, however, has been limited by the lack of high-energy sources. New studies indicating higher terahertz conversion efficiencies [1] open up the possibility of novel applications in high energy density physics. One such application utilizes a terahertz beam to probe an optically excited system. A high-energy terahertz source is currently in development at SLAC National Accelerator Laboratory using optical rectification in lithium niobate with a 20 mJ, 800 nm, 40 fs Ti:Sapphire laser system. A pyroelectric camera is used to obtain the spatial profile of the generated terahertz beam while electro-optic detection is used to measure the full terahertz waveform. We will present the characterization of this source, as well as its potential use in future studies of the electrical conductivity of warm dense matter. [1] S. -W. Huang et al. (2013). High conversion efficiency, high energy terahertz pulses by optical rectification in cryogenically cooled lithium niobate. Optics Letters, 38(5), 796–798.
        Speaker: Chandra Curry (University of Alberta)
      • 433
        Characterization of Initial Target Conditions in High Intensity Laser Solids Interaction Experiments
        Terawatt and Petawatt class high power laser systems have pre-pulses that can significantly affect the interaction physics. For example, in cone-guided high-intensity laser experiments the preformed plasma could cause filamentation and beam refraction [1]. Pre-pulses arrive picoseconds to nanoseconds before the main laser pulse can significantly increase the initial scale length and electron temperature of solid targets. It is important to know the initial target conditions to both correctly interpret the experimental data and to provide realistic initial conditions for theoretical calculations. Pre-pulses that arrive in a nanosecond time scale prior to the main pulse can be measured using fast photodiodes [2-4]. Pre-pulses that arrive in picosecond time scale prior to the main pulse can in principle be characterized using a third order correlator [5]. However, on-shot pre-pulse diagnostic systems are often not readily available for users in many high-power laser facilities. Even if pre-pulse diagnostic systems are available they do not provide direct information about the degree of target disruption. Here, we present a technique for providing information about the degree of target disruption due to pre-pulses. We use a small portion of the laser beam as a probe beam to measure the change of target optical properties induced by the laser pre-pulse. An example using 30nm thin gold film targets will be presented here. The technique with sub-picosecond resolution allows us to detect pre-pulse heating down to 1/5 of the damage threshold energy density. [1] A.G. MacPhee et. al, Phys. Rev. Lett 104, 055002 (2010) [2] Y.Y. Tsui et al., “Prepulse Measurements in Fast Ignition Experiments”, 2010 CAP Congress Invited Talk [3] S. Le Pape et al., Opt. Lett. 34, 2997 (2009) [4]A. Yogo et. al., , Phys. Plasmas 14, 043104 (2007) [5] S. Keppler et al, Appl. Phys. B 104, 11 (2011)
        Speakers: Ying Tsui (University of Alberta), Zhijiang Chen (SLAC National Accelarator Laboratory)
    • DTP Poster Session with beer / Session d'affiches, avec bière DPT CCIS Ground Floor PCL lounge

      CCIS Ground Floor PCL lounge

      University of Alberta

      Convener: Arundhati Dasgupta (University of Lethbridge)
      • 434
        Algorithms for Boson Realizations of SU(n)
        We devise a procedure for calculating boson realizations of canonical basis-states of SU$(n)$ for arbitrary $n$. We employ our boson realization to calculate Wigner $\mathcal{D}$-functions of SU$(n)$ in the canonical Gelfand-Tsetlin basis and connect these functions to outputs from multi-photon interferometry.
        Speaker: Ish Dhand (University of Calgary)
        1
      • 435
        Quantum corrected numerical relativity
        We introduce a non-spherical metric motivated from quantum gravity. We study the time evolution of scalar field induced gravity using numerical methods.
        Speaker: Anindita Dutta (University of Lethbridge)
      • 436
        Bohmian trajectories for harmonic oscillator and Coulomb potentials
        In Bohmian mechanics, quantum particles follow causal deterministic trajectories. These trajectories obey an equation of motion much like Newton's, with the addition of a "quantum potential" linked to the Schrödinger wave function. Quantum probabilities stem from the absence of precise knowledge of initial conditions, and they are recovered exactly if one assumes that initial particle positions are distributed according to the absolute square of the wave function. We give examples of computation of Bohmian trajectories for the harmonic oscillator and Coulomb potentials. Numerical uncertainties are estimated. Our objective is to compute trajectories for distributions of initial particle positions that differ from the absolute square of the wave function, and to investigate the relaxation of the associated probability distributions to the quantum probabilities.
        Speaker: Mr Benjamin Dupuis (Université du Québec à Trois-Rivières)
      • 437
        Unified Theory of Forces
        We are pretty sure about four fundamental forces in the universe. Some of the forces are well behaved and can be explained in different context. Electromagnetism is among the well understood ones. On the other side, gravitational force seems to reveal different faces in various situation and trying to explain it in a unified theorem with other forces has not been successful yet. I have come to conclusion that all the fundamental forces - gravitational, weak, electromagnetism, and strong forces- are one single force. The force that I call spinning force. The spinning force is able explain all the forces and the way they behave in a single complex mathematical model. That is the gravitational force does not propagate in a straight line as it was proposed by classical physicists and it does not affect the imaginary fabric of space; rather the gravitational force proliferate in spinning fashion similar to all other forces . Furthermore, my explanation predicts that there should be more forces that can be result from these fundamental forces (as we call them now). The new force also explains the expansion of universe. Not to mentioned the new force has magnitude of exp(-1448) of strong force. Graphics and equations would make it clear why this force must exist and how it can have dual behaviour. One of the most important fact about these forces is they result from quantified shells of forces. That is at a certain point a new force will spring, which is by product of the previous forces.
        Speaker: Kaveh Mozafari (ExcellenSation)
      • 438
        Tunneling decay of false kinks
        We consider the decay of “false kinks,'' that is, kinks formed in a scalar field theory with a pair of degenerate symmetry-breaking false vacua in 1+1 dimensions. The true vacuum is symmetric. A second scalar field and a peculiar potential are added in order for the kink to be classically stable. As with any tunneling event, the rate is proportional to $\exp{-S_E}$ where $S_E$ is the Euclidean action of the bounce describing the tunneling event. This factor varies wildly depending on the parameters of the model. Of interest is the fact that, when the parameters take values arbitrarily close to the “zones of dissociation”, that is, regions in parameter space where $S_E$ can get arbitrarily small, implying that the kink is only barely stable. Thus, while the translation-invariant false vacuum may be very long-lived, the presence of kinks can give rise to accelerated vacuum decay.
        Speaker: Yvan Ung (University of Montreal)
        Poster
      • 439
        Electric quantum walks without electric field: an optical implementation scheme
        Quantum walks are known to provide a universal platform for quantum algorithms and hence, are useful for quantum computation and information processing. Unlike other methods of simulating quantum protocols, quantum walks can be realized in classical systems. One of the interesting class of quantum walks is the electric quantum walk where the dynamics of the (charged) quantum walker is influenced by an external electric field. In this work we present a scheme to implement this dynamics without the electric field. This is done by using the classical light and a linear optical setup. The walk is performed over the quantized orbital angular momentum of the light beam whereas the optical polarization constitutes the coin space for the walker. The effect of the electric field is also simulated by the linear optical devices. We explore different phases of the dynamics such as the localization and the Bloch oscillations by choosing proper settings of the optical setup. We also study the (non-quantum) entanglement arising between the orbital angular momentum and the optical polarization.
        Speaker: Dr Wei-Wei Zhang (IQST, University of Calgary)
    • PPD Poster Session with beer / Session d'affiches, avec bière PPD CCIS Ground Floor PCL lounge

      CCIS Ground Floor PCL lounge

      University of Alberta

      Convener: Jean-Francois Arguin (Universite de Montreal (CA))
      • 440
        Calibration of the DEAP-3600 photomultiplier tubes
        The DEAP detector uses 255 photo multiplier tubes (PMTs) to detect the faint scintillation light from possible WIMP interactions in liquid argon. A photoelectron released when a scintillation photon strikes the front face of the PMT is amplified inside the PMT, and the resulting single-photoelectron (SPE) charge signal recorded. Due to random fluctuations in the amplification process, the distribution of SPE charge signals is not a sharp line, but a broad bump with a shape unique to each PMT. Knowing the shape of the SPE charge distribution, any measured signal can be related back to the number of photons that struck the PMT. Especially when working with more than one PMT, this normalization between PMTs is crucial to ensuring good energy resolution and to minimize systematic effects on the energy calibration. We present the SPE charge distribution measurement techniques, and a physical model to describe this distribution, as used for calibration of the DEAP-3600 PMTs.
        Speakers: Dr Marcin Kuźniak (Queen's University), Dr Tina Pollmann (Laurentian University)
      • 441
        Simulation study of the use of internal Ar-39 beta decays for energy calibration of the DEAP-3600 detector.
        The DEAP-3600 detector uses natural liquid argon as target material for WIMP interactions. Natural argon contains the beta emitter Ar-39, which will create about 3600 beta events per second, uniformly distributed across the active detector volume. By fitting the shape of the beta spectrum from these events as a function of event position, a position-dependent energy calibration of the whole detector can be found on a timescale of about 10 minutes. This calibration method, using intrinsic internal radioactivity, provides a fast initial calibration for preliminary analyses, and will be used regularly to monitor detector performance. We present the fitting method used to obtain the position dependent energy calibration parameters, as well as the systematic and statistical limits inherent to this method, using Monte Carlo detector simulation results.
        Speaker: Chris Jillings (SNOLAB)
      • 442
        The DEAP-3600 Dark Matter detector
        The current standard model of cosmology relies on the presence of vast amounts of Dark Matter throughout the universe, made from particles that have never been observed in the laboratory. New particles are also predicted from the side of particle physics, where they arise in theoretical extensions that would make the standard model of particle physics consistent. The new particle favoured for constituting Dark Matter is the so-called WIMP, or weakly interacting massive particle. Detecting these particles, should they exist, and ascertaining their properties is a challenging tasks due to their weak interaction strength and very low interaction cross sections. The DEAP-3600 experiment, located 2 km underground at SNOLAB in Sudbury, Canada, uses a 3.6 ton single-phase liquid argon target for a sensitive Dark Matter search. The projected sensitivity to the spin-independent WIMP-nucleon cross-section is 10^−46 cm^2, about one order of magnitude improvement over current searches at 100 GeV WIMP mass. Beside locating the detector deep underground, this high sensitivity is achieved through careful detector design and material selection. We present the overall design and construction of the DEAP-3600 detector.
        Speakers: Pietro Giampa (Queen's University), Dr Tina Pollmann (Laurentian University)
      • 443
        Study of neck alpha backgrounds in the DEAP-3600 dark matter detector
        DEAP-3600 is dark matter detector that will be searching for spin-independent interactions of weakly interacting massive particles with a 1000 kg fiducial volume of liquid argon contained in an acrylic sphere. Strict material selection has been implemented to minimize the presence of uranium and thorium. Alpha decays of these elements in the detector neck will produce scintillation light capable of mimicking a dark matter signal. In order to estimate the backgrounds in the detector, projected material radioactivity levels have been incorporated into Monte Carlo simulations. A likelihood ratio algorithm has been developed based on these simulations to identify possible background events in the DEAP-3600 detector. The results of the Monte Carlo simulations, with focus on the algorithm developed, will be discussed.
        Speaker: Courtney Mielnichuk
      • 444
        In-situ Surface Contamination Removal With the DEAP-3600 Resurfacing Robot
        The success of any Dark Matter experiment depends on the ability of reducing any possible sources of backgrounds. For the DEAP-3600 experiment, surface backgrounds were reduced in-situ by removing more than 100 microns of acrylic from the most inner part of the detector with a resurfacing robot (Resurfacer). This machine was successfully run for over 200 hours, combined with a purge gas system that further eliminated Rn daughters depositions. We will present here the results of the Resurfacer runs, including all different used monitoring methods that allowed to estimate the current surface backgrounds level to be $0.1$ events in 3 years exposure.
        Speaker: Dr Bei Cai (Queen's University)
      • 445
        Skyrmion configurations for Near-BPS Skyrme Models
        The Skyrme model, which was first proposed over half a century ago, is now understood as a low-energy effective theory of QCD where baryons (and nuclei) emerge as topological solitons. It provides a relatively good picture of the nucleons, but it overestimates their binding energies in nuclei by at least an order of magnitude. The present work is based on a recent extension of the original Skyrme model, the so-called near-BPS Skyrme Model. In the pure BPS limit of the model, there exists an infinite dimensional family of solutions with zero binding energy. On the other hand, the solutions that arise from the near-BPS model nearly saturate the Bogomol'nyi bound which means that by construction there must have small binding energies. However, there remains an open question: what solution configuration minimizes the energy? Numerical calculations run into problems when one attempts to provide such an answer. Here, instead, we compare the two most prominent configurations, the axial and rational map ansatz, for a class of hybrid model that goes from the original to the pure BPS Skyrme model. Our results suggest that the axial solution is the lowest energy configurations for the set of parameters for which the binding energy per nucleon B/A agrees best with the experimental data thereby supporting even further the idea that nuclei could be near-BPS Skyrmions.
        Speaker: Mr Nicolas Giasson (Université Laval)
    • Science Policy Committee Breakfast Meeting / Réunion-déjeuner du Comité de politique scientifique CCIS L1-029

      CCIS L1-029

      University of Alberta

      Convener: Kristin Poduska (Memorial University of Newfoundland)
      • 446
        The 2018 Shutdown of the NRU reactor
        The federal government recently announced its decision to shut down the NRU reactor in 2018. The National Research Universal (NRU) reactor commenced operation in 1957, to provide neutrons for several missions simultaneously, including the production of neutron beams to support fundamental experimental research on solids and liquids, advancing knowledge of condensed matter physics. Today, the Canadian Neutron Beam Centre manages six thermal neutron beam lines at the NRU reactor, and sustains a team of scientific and technical experts who enable collaborative research projects to be performed effectively by students and scientists from over 30 Canadian universities, as well as over 100 foreign institutions from about 20 countries. The Canadian Institute for Neutron Scattering has organized a meeting for Canada’s physics community to consider whether and how the imminent loss of this unique Canadian resource should be addressed. This presentation will provide historical context and details of the current situation, as background for an informed conversation about options and actions over the next few years.
    • R1-1 Optomechanics -- minisymposium I (DCMMP-DAMOPC) / Optomécanique -- minisymposium I (DPMCM-DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Frank Marsiglio (University of Alberta)
      • 447
        Magnetic Resonance Spectroscopy with Torsional Optomechanics
        An optomechanically-based magnetic resonance spectrometer will be described. The demonstration of inductive detection of nuclear spin precession, in 1945, launched magnetic resonance spectroscopy as a general-purpose tool. As a complement to this, the precession of magnetic dipoles can be choreographed to yield an AC mechanical torque on a torsion sensor. Optical transduction of mechanical displacement then replaces a measurement of current induced by electromotive force. Circumstances in which torque observations can increase the sensitivity of general-purpose magnetic resonance spectroscopy will be discussed. Work performed in collaboration with J Losby, F Fani Sani, D Grandmont, Z Diao, M Belov, J Burgess, S Compton, W Hiebert, D Vick, K Mohammad, E Salimi, G Bridges, D Thomson. We are grateful for support from NSERC, NINT, AITF, and CRC.
        Speaker: Mark Freeman (University of Alberta)
      • 448
        Quantum Reservoir Engineering in Optomechanical Systems
        The field of quantum optomechanics involves studying the interaction of a mechanical resonator and photons in a cavity. It has seen remarkable progress in the past few years, and holds considerable promise for both fundamental studies of quantum phenomena, as well as applications to quantum information processing and ultra-sensitive detection. In this talk, I will discuss recent theory work exploring how mechanical dissipation can be used as a quantum resource in optomechanics. This kind of "reservoir engineering" allows one to generate both squeezed and entangled light, and also allows the construction of devices which break time-reversal symmetry and reciprocity without the use of magneto-optic effects. While very general, the approaches I discuss are particular well-suited to superconducting circuit realizations of optomechanics.
        Speaker: Aashish Clerk (McGill University)
      • 449
        Nanophotonic Optomechanics in Diamond
        Single crystal diamond is a desirable material for use in nanophotonics and optomechanics thanks to its well known excellent optical and mechanical properties. However, one can argue that diamond's most compelling characteristic its ability to host color center defects, such as the nitrogen vacancy, whose spin can be used to store and manipulate quantum information. These "artificial atoms" can be controlled optically, as well as mechanically through local stress fields. We have developed single crystal diamond optomechanical devices which allow optical coupling to ultrahigh quality factor (720 000) mechanical resonances with a sensitivity approaching the standard quantum limit. Using this optomechanical interface, we have excited nanomechanical self-oscillations, and have demonstrated optical cooling to sub-Kelvin temperatures. Our presentation will review this work, and discuss efforts to couple optomechanical excitations to single spin in diamond.
        Speaker: Paul Barclay (University of Calgary)
      • 450
        High cooperativity optomechanics with wide-bandgap materials
        Cavity optomechanics provides a platform for exquisitely controlling coherent interactions between photons and mesoscopic mechanical excitations. Cavity optomechanics has recently been used to demonstrate phenomena such as laser cooling, optomechanically induced transparency, and coherent wavelength conversion. These experiments were enabled by photonic micro- and nanocavities engineered to minimize optical and mechanical dissipation rates, $\gamma_o$ and $\gamma_m$, respectively, while enhancing the per-photon optomechanical coupling rate, $g_0$. The degree of coherent photon-phonon coupling in these devices is often described by the cooperativity parameter, $C = N g_0^2 / \gamma_o\gamma_m$, which may exceed unity in several cavity optomechanics systems for a sufficiently large intracavity photon number, $N$. Here we demonstrate optical whispering gallery mode (WGM) microdisk cavities that are fabricated from wide-bandgap materials such as gallium phosphide (GaP), and single crystal diamond (SCD). By using wide-bandgap materials high-$C$ can be achieved by reaching high-$N$ before thermal instabilities occur. We demonstrate GaP microdisks with intrinsic optical quality factors $> 2.8 \times 10^5$ and mode volumes $< 10(\lambda/n)^3$, and study their optomechanical properties. We observe optomechanical coupling in GaP microdisks between optical modes at 1.5 $\mu$m wavelength and several mechanical resonances, and measure an optical spring effect consistent with a predicted optomechanical coupling rate $g_0/2\pi \sim 30$ kHz for the fundamental mechanical radial breathing mode at 488 MHz. We have also demonstrated monolithic microdisk cavities fabricated from bulk SCD via a scalable process. Optical quality factors of $ 1.15 \times 10^5$ at 1.5 $\mu$m are demonstrated, which are among the highest measured in SCD to date, and can be improved by optimizing our fabrication process further. In addition to SCD-possessing desirable optical properties, its high Young’s modulus, high thermal conductivity, and low intrinsic dissipation, show great promise for use in high-$C$ optomechanics. Current investigation is focused on characterizing the optical properties of these devices, and optimizing them for applications in nonlinear optics and quantum optomechanics.
        Speaker: Mr Matthew Mitchell (University of Calgary)
      • 451
        Optomechanical Micro-Macro Entanglement.
        Vigorous efforts are currently being undertaken to bring quantum effects such as superposition and entanglement to the macroscopic level. One prominent goal in this context is the creation of entanglement between a microscopic and a macroscopic system, following Schrödinger’s famous thought experiment that involved a decaying nucleus and a cat. A natural setting for testing these predictions would be quantum optomechanics, where we study the interaction of light with mechanical devices at the quantum level. In our work (R. Ghobadi, S. Kumar, B. Pepper, D. Bouwmeester, A. I. Lvovsky, and C. Simon, “Optomechanical Micro-Macro Entanglement”, Phys. Rev. Lett. 112, 080503 (2014)), we propose to create and detect optomechanical entanglement by storing one component of an entangled state of light in a mechanical resonator, and then retrieving it. Successful demonstration of entanglement for the retrieved light then demonstrates the existence of optomechanical entanglement in the intermediate state. We propose to first create purely optical micro-macro entanglement by amplification (displacement in the phase space) of one component of an initial microscopic entangled state as was recently demonstrated. For optomechanical micro-macro entanglement, we convert the photons in the amplified component into phonons. The phonons are then reconverted into photons. Next, we de-amplify (again by displacement in the phase space) these photons and verify entanglement using homodyne detection. We show that this method also makes it possible to create an optomechanical “cat state”, which is a superposition of macroscopic states. We apply this general approach to two mode squeezed states where one mode undergoes a large displacement in phase space. Based on an analysis of the relevant experimental imperfections, the scheme appears feasible with current technology.
        Speaker: Mr Sourabh Kumar (Institute for Quantum Science and Technology, Department of Physics and Astronomy, University of Calgary, Calgary T2 N 1N4, Alberta, Canada)
        Slides
    • R1-2 Computational Biophysics (DMBP-DCMMP) / Biophysique numérique (DPMB-DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Maikel Rheinstadter (McMaster University)
      • 452
        Molecular Theory of Solvation Based Miltiscale Modeling of Biomolecular Systems and Functions
        The three-dimensional reference interaction site model with the Kovalenko-Hirata closure (3D-RISM-KH molecular theory of solvation) is Ornstein-Zernike type integral equation theory of liquids. Based on first principles of statistical mechanics, the 3D-RISM-KH theory consistently accounts for effect of chemical specificities of solvent, co-solvent, ions, and ligands on biomolecules solvation structure and thermodynamics, including steric forces, hydrophobicity, hydrogen bonding, and other effective interactions. It enables predictive modeling of complex chemical and biomolecular systems problematic or not feasible for molecular simulation or continuum solvation treatment: • 3D-RISM-KH structural water detection and placement has been implemented in the Amber Tools and Molecular Operating Environment (MOE) packages. Structural water is critical in reproducing ligand binding modes and protein aggregation; case studies include the Maltose-Binding Protein, and HET-s prion and Aβ oligomer and fibril formation. • 3D-RISM-KH supplemented with the partial molar volume correction (aka “Universal Correction”) provides excellent agreement with experimental data on a large set of small compounds for solvation free energies in octanol and water, and so accurately predicts octanol-water partition coefficients. • Treating flexible ligands decomposed into fragments as solution species, the 3D maps of potentials of mean force obtained from 3D-RISM-KH define scoring functions interfaced with the AutoDock package for automated ranking of docked conformations. The predicted location and residency times of the modes of binding of a flexible thiamine molecule to the prion protein at near-physiological conditions are in excellent agreement with experiment. • 3D-RISM-KH reveals chemistry-driven nanoscale forces that control the resilient structure of plant cell walls formed by cellulose microfibrils in a matrix of hemicellulose and lignin, crucial for enzymatic and chemical deconstruction of biomass. It predicts effective interactions of cellulose nanocrystals (CNC) with pristine and functionalized surface in water, electrolyte solutions, organic solvents, and ionic liquids, so as to help design modified CNC with improved dispersion and preserved mechanical properties that can be effectively incorporated into nanocomposite materials. • Multi-time-step MD of biomolecules steered with mean solvation forces obtained from 3D-RISM-KH at outer time steps and treated with generalized solvation force extrapolation (GSFE) at inner timesteps is efficiently stabilized with the optimized isokinetic Nosé-Hoover chain (OIN) thermostat and accurately reproduces conformational properties, as validated on hydrated alanine dipeptide, miniprotein 1L2Y, and protein G. This quasidynamics results in time scale compression of protein conformational changes coupled with solvent with respect to real time dynamics and provides up to 1000-fold effective speedup, compared to conventional MD with explicit solvent. This enables folding the miniprotein from a fully denatured state in 60 ns quasidynamics, cf. 4-9 μs physical folding time.
        Speaker: Dr Andriy Kovalenko (Natinal Institute for Nanotechnology, and Department of Mechanical Engineering, University of Alberta, 11421 Saskatchewan Dr., Edmonton, AB, T6G 2M9, Canada)
      • 453
        Frontiers in Membrane Biophysics
        One of the major challenges of modern physics is to contribute to biology and life-sciences. Neutron and X-ray beams are prime tools to study molecular structure and dynamics in membranes in-situ, under physiological conditions [1]. The experiments give access to nanoscale diffusion processes within and across the membranes, effects of macromolecules on membrane properties, such as ethanol and cholesterol, the interaction with common drugs, such as aspirin and ibuprofen, and potential side effects, detection and characterization of raft structures and protein-protein interactions in Alzheimer’s disease. The quantitative measurements lend themselves for comparison with computer simulations. I will talk about current topics in membrane biophysics, the associated experimental challenges and present exciting recent results and potential biomedical applications. [1] http://www.rheinstaedter.de/maikel/publications/publications.htm
        Speaker: Maikel Rheinstadter (McMaster University)
      • 454
        Bridging the gap between theoretical and experimentally inferred reorganization energy
        Biological electron transfer (ET) reactions are fundamental to the production of energy in all living cells. Efficient, site-selective electron transfer is crucial for effective metabolic processes to sustain life. An accurate description of the electron transfer process through a protein complex is lacking. In particular, with the MADH and amicyanin protein complex, found in the bacteria *Paracoccus denitrificans*, there is a disagreement between the theoretical prediction and the experimentally inferred reorganization energy. The reorganization energy is a poorly understood yet key element in describing qualitatively electron transfer though a metabolic protein complex. Attempts at better understanding the energetics of the reaction involve adapting Marcus thoery, the wildly successful model for simple electron transfer reactions yet problematic for complex systems. Previous work suggest a new model which includes electrostatic interactions between the protein complex and surrounding solvent in to the reorganization energy. In this theoretical work, we investigate the validity of the new model for ET in the MADH-amicyanin protein pair. The MADH-amicyanin system is chosen in part for its particular use of water in the active site of the reaction. We perform classical molecular dynamic simulations of the solvated protein pair. A set of trajectory steps/frames from the simulations are then analyzed using the combined quantum mechanical and molecular mechanical (QM/MM) scheme to calculate interaction energies. The molecular simulations performed in this investigation further support the importance of the solvent’s role in the ET process. Furthermore, we provide evidence that the discrepancy between the theoretical and the experimentally inferred values of the reorganization energy can be minimized by including the protein-solvent interactions in the model.
        Speaker: Jonathan Johannes
        Slides
      • 455
        Oxygen distribution in the liver lobule: Three dimensional computational Models
        We develop a computational model for the transport and metabolism of drugs as well as oxygen in the functional unit of the liver called the lobule. The functional unit of an organ is the smallest structural unit that can independently serve all of the organ’s functions. In previous studies, starting from a simple idealized model of the lobule composed of liver cells and sinusoid flow paths, we discussed the effects of structural variation and inhomogeneity on the sinusoids flow properties and related this to random distributions, and fractal and percolation concepts. As well, possible effects of metabolic zonation of liver cells on drug concentration levels inside the lobule were considered. Zonation has been attributed primarily to non-uniform distribution of oxygen across the lobule, with the periportal zone experiencing relatively high concentrations of oxygen while the perivenal zones see near hypoxic levels of oxygen. Here, we apply our model to track oxygen distribution and metabolism across the lobule. Since oxygen is small molecule, molecular diffusion can be expected to play a dominant role. Furthermore, to capture more realistic structures, we introduce 3D hexagonal based models with one input (arterial blood flow from the portal vein) and six outputs (hepatic veins) to represent a typical liver lobule. We also implement a novel sequential diffusion-limited aggregation (DLA) method in constructing the sinusoidal network in the lobule to mimic their realistic structural variation. With this approach, we are able to analyze predicted drug concentration levels observed exiting the lobule and relate this with their detailed distribution inside the lobule, and compare the results with our earlier idealized lobule models. The convective-diffusive-reactive problem was solved and the resulting steady state flow of oxygen on this 3D structure is furthermore used to predict the oxygen-generated enzyme distributions in liver cells responsible for lobule zonation. Such analysis indicates the variability of response which can be expected from individual lobule sections in healthy livers due to modified convective structures in this well-vascularized tissue. Since various liver diseases can be thought to produce structural variations in the lobule, our analysis also gives insight into the role of disease on liver function and performance.
        Speaker: Vahid Rezania (MacEwan University)
      • 456
        Inferring compactness and asphericity of disordered protein ensembles by single molecule FRET spectroscopy and coarse grained simulations
        A large number of proteins, termed intrinsically disordered proteins (IDPs), fail to fold into well-defined three-dimensional structures. Many of these IDPs are associated with diseases, such as cancer or neurodegenerative disorders. In contrast to well-folded proteins, the polymer properties of IDPs are often crucial aspects of their functions. Correspondingly, to develop a better understanding of how disorder is used in function, we used a quantitative polymer-physics-based approach to analyze data from single-molecule FRET (smFRET) spectroscopy experiments. We infer the properties of the conformational ensemble by matching an experimental average transfer efficiency $ \rm \langle E \rangle_{exp}$ with one that is computed from a distribution $\rm P(R_{ee})$ of end-to-end distances $\rm R_{ee}$. In a refinement of the conventional approach, we use extensive sampling of coarse-grained protein chains with excluded volume to generate physically realistic $\rm P(R_{ee}|R_{g},A)$ conditioned on the radius of gyration $\rm R_{g}$ (a description of compactness) and asphericity A (a description of shape). This methodology is applied to residues 1-90 of the intrinsically disordered Cdk inhibitor Sic1, resulting in ensembles that are more compact than those deduced by conventional procedures which assume a Gaussian chain model without excluded volume. This result is in good agreement with SAXS measured Rg data and NMR measurements of the hydrodynamic radius. In future studies, this methodology will be applied to refine a polyelectrostatic model for phosphorylated Sic1’s ultrasensitive interaction with Cdc4 by providing information on the conformational shape and dimensions of bound and free phosphorylated Sic1, and to test whether possible adjustments to the polarizable charge distribution impact binding affinity.
        Speaker: Mr Gregory Gomes (Department of Chemical and Physical Sciences, University of Toronto Mississauga and Department of Physics, University of Toronto)
      • 457
        Effects of Bacterial Specimen Preparation on Laser-Induced Breakdown Spectra
        There is an urgent need in the medical, environmental health and safety, security, and food-processing industries for a technology capable of rapid and sensitive bacterial pathogen identification. In response to this, we have shown that laser-induced breakdown spectroscopy (LIBS) can be used as a real-time elemental assay capable of discriminating between bacteria at both the species and strain levels. Recent experiments have been conducted to make this technique more attractive to professionals in a clinical setting while increasing the ability to acquire high signal-to-noise measurements from bacterial specimens in liquid suspension. We have introduced a new method of bacterial mounting using clinician-friendly nitrocellulose filters. We have also conducted viability studies to address the possibility of sample sterilization prior to testing, greatly reducing the risk associated with handling these pathogens. In this poster, we will present these results as well as a multivariate bacterial classification based on the elemental content of four bacterial species, *E. coli*, *S. epidermidis*, *M. smegmatis*, and *P. aeruginosa*, that have all been sterilized via autoclave. We also compare changes in the LIBS spectra associated with various methods of cellular inactivation including sonication and bactericidal UV exposure.
        Speaker: Dylan Malenfant (University of Windsor)
    • R1-3 Status and Future of Precision Frontier (PPD-DTP-DIMP) / État et avenir de la frontière de précision (PPD-DPT-DPIM) CCIS L1-029

      CCIS L1-029

      University of Alberta

      Convener: Bei Cai (Queen's University)
      • 458
        Status and Prospects for Theoretical Studies of B-meson Decays
        Physics beyond the Standard Model (BSM) affects low-energy processes such as meson decays through loop-suppressed contributions. Precision physics to separate loop-level corrections are therefore considered vital for the discovery of BSM physics at the intensity frontier. I will describe the current status of research in the field of $B$ decays, concentrating on its role in establishing the Cabibbo-Kobayashi-Maskawa (CKM) paradigm, the theoretical difficulties in going beyond the CKM and how some of these problems may be overcome. The discussion will include the status and prospects of studying select meson-decay channels that may play a role in future discoveries of BSM physics.
        Speaker: Dr Bhubanjyoti Bhattacharya (University of Montreal)
        Slides
      • 459
        The forward-backward asymmetry in $B\to K^*\mu^+\mu^-$.
        The forward backward asymmetry distribution for the rare dileptonic decay $B \to K^* \mu^+ \mu^-$ in the region below the $J/\psi$ resonance is calculated. We use the form factors for $B\to K^*$ transition which are predicted by the anti-de Sitter/Quantum Chromodynamics (AdS/QCD) correspondence. We compare our results with those obtained from QCD sum rules.
        Speaker: Mohammad Ahmady (Mount Allison University)
        Slides
      • 460
        Isospin asymmetry in B→K∗μ+μ− using AdS/QCD
        We compute the isospin asymmetry distribution in the rare dileptonic decay B→K*μ+μ-, in the dimuon mass squared (q2) region below the J/Ψ resonance, using nonperturbative inputs as predicted by the anti–de Sitter/quantum chromodynamics correspondence and by sum rules. We predict a positive asymmetry at q2=0 which flips sign in the region q2∈[1,2]  GeV2 to remain small (≤2%) and negative for larger q2. While our predictions are distinct as q2→0, they become hardly model-dependent q2≥4  GeV2. We compare our predictions to the most recent LHCb data.
        Speaker: Dr Ruben Sandapen (Mount Allison University & Universite de Moncton)
      • 461
        The Belle II Experiment at the SuperKEKB e+e- Collider
        Belle II will probe the 'flavour sector' of particle physics at the high-luminosity SuperKEKB e+e- collider, located at the KEK laboratory in Japan. Accelerator commissioning will start in 2016, with the goal of collecting 50 inverse attobarns of data by 2024, which is thirty times the combined integrated luminosity of the two previous generation B-factories, PEP-II at SLAC and KEKB at KEK. This precision-frontier facility will open an exciting window on new energy scales beyond the reach of existing colliders, including the LHC, by virtue of quantum loops corrections that are sensitive to very massive, and as yet undiscovered, particles. These hypothesized particles manifest themselves in precision measurements of processes involving bottom and charm quarks and tau leptons, such as CP violation and other asymmetries, rare decays, and processes that are forbidden within our current understanding of physics. This presentation will provide an overview of the physics and status of the Belle II/SuperKEKB project with a focus on the Canadian contributions.
        Speaker: Michael Roney (University of Victoria)
        Slides
      • 462
        Radiation Hardness of Thallium Doped Cesium Iodide Scintillation Crystals
        To prepare for the large backgrounds expected to be present in the Belle II detector from the SuperKEKB e+e- collider, the radiation hardness of several ($5 \times 5 \times 30 \text{cm}^3$) thallium doped cesium iodide scintillation crystals are studied to accumulated $\sim 1$ MeV photon doses of up to 1000 Gray. The sample set of crystals studied consists of 2 spare crystals from the Belle experiment and 8 crystals from the BaBar experiment. The two Belle crystals and two of the BaBar crystals are readout using pin diodes glued to the crystal face while the remaining 6 BaBar crystals are readout using a PMT. The crystals are dosed in 6 stages. At each stage all crystals are given uniform dose profiles except for one BaBar crystal which was dosed face on giving a longitudinally non-uniform dose profile. Using Cesium-137 and Bismuth-207 sources and cosmic rays, the longitudinal uniformity of the crystals light yield, scintillation decay times, time resolution and energy resolution are measured at each stage and compared to non-dosed reference crystals. In addition to experimental work, Monte Carlo simulations using Geant4 are used to further understand the baseline experiments and to study the expected effects of radiation damage at SuperKEKB.
        Speaker: Mr Savino Longo (University of Victoria)
    • R1-4 Energy frontier: Standard Model and Higgs Boson II (PPD) / Frontière d'énergie: modèle standard et boson de Higgs II (PPD) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Manuela Venturi (University of Victoria (CA))
      • 463
        Before and After - Consequences of the Higgs Discovery
        The discovery of a new resonance consistent with the standard model Higgs boson has had a drastic effect on predictions of new physics. Everything about the discovery, from the mass, to the spin, to the production and decay rates tells us about the stability of the Higgs and the nature and scale of new physics. In this talk, I will discuss the consequences of the discovery of the Higgs boson in terms of its effect on predictions of beyond the standard model physics, with a focus on theories of supersymmetry and extended electroweak sectors.
        Speaker: Dr Travis Martin (TRIUMF)
        Slides
      • 464
        Search for new SM Higgs decays and production mechanisms, and BSM Higgs production
        In the presentation, latest results in search for Higgs boson decays and production mechanisms in the SM as well as BSM context will be presented. The focus will be on rare decays which were not directly observable during the Run1 data taking period (integrated luminosity of approximately 25 fb-1), these will be then compared with expectations for the full High Luminosity LHC Upgrade assumptions of total integrated luminosity of 3000 fb-1. The upgrade potential for the scenarios searching for physics beyond Standard Model will be discussed as well.
        Speaker: Richard Polifka (University of Toronto (CA))
        Slides
      • 465
        Search for an Invisibly Decaying Higgs Boson Produced via Vector Boson Fusion in pp Collisions at s√=8 TeV using the ATLAS Detector at the LHC
        A search for Higgs bosons produced via vector boson fusion and decaying into invisible particles using 20.3 fb−1 of 8 TeV data recorded by the ATLAS detector at the LHC is presented. Data-driven techniques are used to estimate the main Standard Model backgrounds. For a Higgs boson with a mass of 125 GeV and assuming the Standard Model production cross-section, an upper bound of 0.29 is set on the branching fraction of H→ invisible at 95% confidence level, where the expected upper limit is 0.35.
        Speaker: Reyhaneh Rezvani (Universite de Montreal (CA))
        Slides
    • R1-5 Quantum Gravity and Quantum Cosmology (DTP) / Gravité quantique et cosmologie quantique (DPT) CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Arundhati Dasgupta (University of Lethbridge)
      • 466
        Low-scale gravity phenomenology
        Less than two decades ago, brane world scenarios offered paradigms to reinterpret the 4-D Planck scale as an effective gravity scale arising for a more fundamental lower gravity scale in higher dimensions. These ideas allowed new phenomenological models to be developed and helped guide searches for low-scale gravity at the Tevatron and LHC. One of the most exciting outcomes of these models is the possibility to produce non-perturbative gravitational states at the LHC. The LHC experiments have recently publish a round of search for non-perturbative gravitational states which seriously confront the models for the first time. I will discuss how the models can now be view in the light of the experimental constraints.
        Speaker: Douglas Gingrich (University of Alberta (CA))
        Slides
      • 467
        A Correlated Worldline Theory of Quantum Gravity
        It is argued that gravity should cause a breakdown of quantum mechanics, at low energies, accessible in principle to table-top experiments. I show that one can formulate a theory of quantum gravity in which gravitational correlations exist between worldline or worldsheet paths, for the particle or field of interest. Using a generalized equivalence principle, one can give a unique form for the correlators, yielding a theory with no adjustable parameters. Quantitative calculations are carried out in a background field effective theory, applicable to all energies of experimental interest. A key feature of the theory is the "bunching" of quantum trajectories caused by the gravitational correlations - this is NOT a decoherence or a "collapse" mechanism. This bunching causes a very rapid breakdown of the superposition principle for energies above 8 orders of magnitude below the Planck mass. In table-top experiments, large slow-moving masses also exhibit this effect, which suppresses all coherence and entanglement phenomena.
        Speaker: Prof. Philip Stamp (UBC)
        Slides
      • 468
        Discreteness of Space in a Weak Gravitational Field
        Quantum gravity induced modifications of position/momentum commutation relation brings about a modification of the Heisenberg's uncertainty principle, to what is known as the generalized uncertainty principle (GUP). It has been shown earlier that the GUP-induced corrections to the Schrödinger equation, when applied to a non-relativistic particle in a one-dimensional infinite potential well, gives rise to the quantization of length. Similar corrections to the Klein-Gordon and the Dirac equations, when applied to a relativistic particle in a three-dimensional box, give rise to area and volume quantizations. This not only suggests that the fundamental structure of space is granular, but also affirms the existence of a minimum measurable length which has long been predicted by the candidate theories of quantum gravity. It is quite natural to investigate how gravity, which is considered as a manifestation of spacetime curvature, might influence this discreteness of space. In this work, the above-stated results of length, area and volume quantization have been extended to cases with a weak background gravitational field. By adding the classical form of a linear gravitational potential to the above three quantum equations, we show that the spatial dimensions inside the box are quantized. Although the nature of quantization is quite complex compared to the cases without gravity, not surprisingly it reduces to the quantization in flat spacetime under proper limits. These results show that the discreteness of space holds in flat as well as in slightly curved spacetimes, further indicating the universality of quantum gravity effects.
        Speaker: Soumen Deb (University of Lethbridge)
        notes
        Slides
      • 469
        Modifications of Heisenberg's Uncertainty Principle Motivated by Quantum Gravity
        As it is currently not possible to access the natural energy scale of quantum gravity (the Planck scale), it is important to look for low-energy effects, e.g. the quantum gravity induced perturbative corrections to non-relativistic quantum mechanics. One such avenue of approach is studying the corrections to the Schrödinger equation via the Generalized Uncertainty Principle (GUP) proposed in various candidate theories of quantum gravity. GUP corrections to the simple harmonic oscillator in phase space will be shown by way of the Wigner function. This GUP-corrected Wigner function will then be compared to the simple harmonic oscillator Wigner function (with no GUP corrections). The changes in the resultant marginal probabilities indicate that there may be observational consequences.
        Speaker: Mr Matthew Robbins (University of Lethbridge)
        Slides
      • 470
        Gravity and dust in 2+1 dimensions
        We study a pressureless dust coupled to gravity with an arbitrary cosmological constant $\Lambda$ in 2+1 dimensions. This theory has interesting classical solutions and yet remains simple enough to explore the non-perturbative quantization of gravitational degrees of freedom. On the classical side we find the Banados-Teitelboim-Zanelli black hole as a static solution when $\Lambda<0$, and for $\Lambda=0$ we find solutions with moving apparent horizons. We are able to quantize a sector of the classical solution space, and look in particular at the horizon operator which measures the location of apparent horizons. Notably, this operator is found to have a non-zero variance on coherent states, implying that apparent horizons are subject to quantum fluctuations.
        Speaker: Dr Jonathan Ziprick (urn:Google)
        Slides
      • 471
        Particle detectors in (curved) space: the equivalence principle and QFT.
        Classically, the equivalence principle tells us that an observer cannot determine the global structure of spacetime using local measurements. After reviewing previous results demonstrating the sensitivity of detectors to spacetime, I proceed to our most recent result: that one can distinguish between a detector in flat space and one inside a hollow spherical shell by measuring the energy required to switch it on and off. These results suggest that, in principle, a particle detector can be used to probe the shape of spacetime far away from the detector itself due to the non-local nature of quantum fields.
        Speaker: Keith Ng (University of Waterloo)
    • R1-6 Testing Fundamental Symmetries II (DTP-PPD-DNP) / Tests de symétries fondamentales II (DPT-PPD-DPN) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: David Morrissey (TRIUMF)
      • 472
        The Hunt for Physics Beyond the Standard Model at the Precision Frontier
        The best way to search for the physics beyond the Standard Model (SM) is by using a diverse set of probes - not just at the energy and the cosmic frontiers, but also the low-energy measurements relying on high precision and high luminosity. Precision tests of the SM, using parity-violating (PV) interaction, gives us possibility to reach the TeV scale, which is complimentary to the LHC searches for the possible extensions of the SM. High precision PV measurements could indirectly point out to the new physics particles if any inconsistency is found between experimental and theoretical results. The talk will review and outline latest advances in precision PV searches for the physics beyond the SM and concentrate on how new physics particles (such as Z’ or dark photon) influence PV observables.
        Speaker: Aleksandrs Aleksejevs (Memorial University of Newfoundland)
        Slides
      • 473
        Initial Results from the TRIUMF PIENU Experiment
        The $\pi\rightarrow e \nu$ branching ratio $R_\pi= \frac{ \Gamma(\pi\rightarrow e \nu + \pi\rightarrow e \nu \gamma)}{\Gamma(\pi\rightarrow \mu \nu + \pi\rightarrow \mu \nu \gamma)},$ one of the most precisely calculated weak interaction Standard Model observables involving quarks, provides a sensitive test of lepton universality and severe constraints on many new physics scenarios with mass reach up to 1000 TeV. The PIENU experiment at TRIUMF aims to measure $R_\pi$ to a precision of less than 0.1%. Results will be presented from an analysis of a subset of the data with statistical and systematic uncertainties reduced to the 0.2% level, significantly improving on previous experiments. Prospects for analyzing the full data set and further reducing the systematic error will also be discussed.
        Speaker: Mr Tristan Sullivan (University of British Columbia)
      • 474
        Simultaneous Spin Measurement for Ultra Cold Neutrons at TRIUMF
        A high intensity UCN source, and an experiment to measure the neutron Electric Dipole Moment (nEDM) are being developed for TRIUMF. Some new physics extensions to the standard model predict nEDM VALUES both above the present limit on the nEDM leading to their abandonment, and just below the present limit where there are several other model predictions vulnerable to the same fate. This talk will present the research and development being done to design an ultra cold neutron detector which is capable of handling the proposed high instantaneous neutron rates in future nEDM measurements. Motivation for, and initial designs of a detector for a simultaneous spin measurement will be presented.
        Speaker: Blair Jamieson (University of Winnipeg)
        Slides
      • 475
        High-voltage breakdown studies with Xe-129 for an nEDM experiment at TRIUMF
        Measuring the neutron Electric Dipole Moment (nEDM) would help answer fundamental cosmological questions like why matter dominated over antimatter even though they are thought to be produced at equal amounts after the Big Bang. One of the main sources of the systematic uncertainties in the recent nEDM experiments was related to magnetic field fluctuations. For the KEK-RCNP/TRIUMF experiment we aim to use a Xe-129 optical co-magnetometer which is expected to record magnetic temporal variations contributing to statistical and systematic errors less than what the Hg-199 co-magnetometer has in the past. This is mainly due to the smaller neutron absorption cross section and the negative (as that of the neutron) gyromagnetic ratio that Xe-129 possesses. The dielectric properties of Xe-129 in the mTorr region where the optical signal will be strong enough have to be explored as the Ramsey resonance technique of the experiment requires a stable electric field of about 12.5 kV/cm in order to improve the current nEDM upper limit. The objective of the experimental work carried out at TRIUMF is primarily to find the relation between the breakdown voltage and the Xe-129 pressure for given electrode geometry and material. In addition to that, the possibility of using Xe-129 in a mixture with other gases (as Hg-199 and He-4) is being explored.
        Speaker: Dr Katerina Katsika (TRIUMF)
        Slides
      • 476
        Current Status of a Measurement of Hadronic Parity Violation in the Capture of Cold Neutrons on Helium-3
        The n3He experiment aims to measure the parity violating asymmetry in the direction of proton emission from the capture polarized cold neutrons in an unpolarized gaseous $^3$He target from the reaction $\vec{n}+^3He\rightarrow T+p$. The size of the asymmetry is estimated to be $(-9.5 \rightarrow 2.5)\times 10^{-8}$, and our goal measurement accuracy is $2\times10^{-8}$. The asymmetry is a result of the low energy weak interaction between quarks and its measurement will provide a benchmark for modern effective field theory calculations. The experiment uses a $^3$He multiwire ionization chamber as the combined target and detector operated in current mode. Simulation is required study the ideal behavior of the chamber and verify it works as expected. To simulate the charge collection in the chamber Garfield++ is used to simulate the electron avalanches and ion mobility in the wire chamber fields. 3D field maps are generated using Gmsh and Elmer. Garfield++ does not simulate low energy particles ionizing gas so it is paired with a Geant4 simulation for charge deposition in the chamber. The experiment is currently running at the Oak Ridge National Lab (Tennessee, USA) and I will report on the simulation of, and initial data taken with the chamber.
        Speaker: Mr Mark McCrea (University of Manitoba)
        Slides
      • 477
        FUNDAMENTAL PHYSICS WITH ULTRA-COLD NEUTRONS COMES TO CANADA
        The knowledge of fundamental properties of the neutron helps us understand many aspect of the universe. It all starts right after the Big Bang: matter wins over antimatter in the Universe, making our existence possible. The main ingredient to that, matter anti-matter asymmetry, requires major violation of another fundamental symmetry, called CP violation. This, in turn might show up in a non-zero electric dipole moment (EDM) of the neutron, making EDM measurements the flagship of fundamental neutron physics. The lowest limits on this quantity have been set by experiments using very slow neutrons (v < 7 m/s), called ultra-cold neutrons (UCN), the best being d<2.9e-26 ecm. UCNs have energies in the 100 neV region and can be manipulated and stored in traps via gravitational, strong and electromagnetic interaction. The presentation will introduce the concept of neutron EDM measurements, ultra-cold neutrons and their production at the upcoming ultra-cold neutron facility at TRIUMF, Vancouver. It will give a status update and an outlook on the physics that can be done with UCN.
        Speaker: Rüdiger Picker (urn:Google)
        Slides
    • R1-7 Hadronic Structure (DNP-DTP) / Structure hadronique (DPN-DPT) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Prof. Garth Huber (University of Regina)
      • 478
        Commissioning of the GlueX Experiment
        The primary goal of the GlueX experiment is to conduct a definitive mapping of states in the light meson sector with an emphasis on searching for exotic hybrid mesons as evidence of gluonic excitations, in an effort to understand the phenomenon of confinement in Quantum Chromo Dynamics. The experiment, housed in the new Hall-D facility at Jefferson Lab following its accelerator upgrade to 12~GeV, is now in its commissioning and calibration phase with data taking expected in 2016. The key features of this compelling physics program will be presented together with an overview of early performance of the detector systems, focusing on the electromagnetic barrel calorimeter (BCAL), built at the University of Regina. The BCAL is a ``spaghetti calorimeter'', consisting of layers of corrugated lead sheets, interleaved with planes of 1-mm-diameter, double-clad, scintillating fibres, bonded in the lead grooves using optical epoxy. The detector will consist of 48 trapezoidal modules and will be readout using 3,840 large-area Multi-Photon Pixel counter arrays.
        Speaker: Prof. Zisis Papandreou (Uinversity of Regina)
      • 479
        QCD Sum Rule Analysis of Heavy-light Hybrids for $J^{P}=1^{-}$
        Quantum chromodynamics (QCD) predicts many bound states that have not yet been conclusively identified, and as more charmonium-like XYZ states are being discovered, interest is increasing in matching these theoretical bound states with experimental observation. Among these states are hybrid mesons: bound states of a quark, an antiquark, and a gluon. With upcoming experiments such as GlueX, and PANDA, experimental data within the expected mass ranges of hybrids will be abundant in the next decade, and theoretical predictions are needed to help identify them. We present preliminary aspects of a QCD sum rule analysis of a heavy-light (open-flavour) $J^{P}=1^{-}$ hybrid system, including non-perturbative condensate contributions up to six dimensions.
        Speaker: Mr Jason Ho (University of Saskatchewan)
      • 480
        QCD and the XYZs
        Many of the charmonium-like XYZ resonances observed by Belle, Babar, CLEO and BESIII collaborations in the past decade are difficult to interpret as conventional quark-antiquark mesons. After a brief review of the XYZ resonances, theoretical scenarios for these states will be presented with an emphasis on results from QCD sum-rule methods.
        Speaker: Tom Steele (U of Saskatchewan)
        Slides
    • R1-8 Interactive Teaching - Teaching with Technology (DPE) / Enseignement interactif et à l'aide de la technologie (DEP) CCIS L1-160

      CCIS L1-160

      University of Alberta

      Convener: Martin Williams (University of Guelph)
      • 481
        Student Centered Active Learning Environment with Upsidedown Pedagogies
        How do you keep a classroom of 100 undergraduates actively learning? Can students practice communication and teamwork skills in a large class? How do you boost the performance of underrepresented groups? The SCALE-UP Project has addressed all these questions. Classes in all the STEM areas plus many in the humanities are currently being offered at more than 250 institutions around the world. Educational research indicates that students should collaborate on interesting tasks and be deeply involved with the material they are studying. We promote active learning in a redesigned classroom for 100 students or more. (Of course, smaller classes can also benefit.) Classtime is spent primarily on “tangibles” and “ponderables”—hands-on activities, simulations, and interesting questions. There are also hypothesis-driven labs. Two or three teams of three-student teams sit at tables that are specially designed to facilitate collaboration. Instructors circulate and engage in Socratic dialogues. The setting looks like a restaurant, with lively interactions nearly all the time. A study of physics learning in the space found: · Female failure rate is 1/5 of previous levels, even though more is demanded of students · Minority failure rate is 1/4 that seen in comparable, traditionally taught courses · At-risk students are more successful in later engineering courses · Conceptual learning and problem solving are improved, with same content coverage This talk will describe the changing demographics and technical background of today’s students and how we modified instruction to account for and even take advantages of changes.
        Speaker: Robert Beichner (North Carolina State University)
      • 482
        Helping Students to get a Better Understanding of Concepts; ‘Course Dossier Method’
        It has been argued that for novice students to acquire a full understanding of scientific texts, they also need to pursue a recurrent construction of their comprehension of scientific concepts. The course dossier method has students examine concepts in multiple passes; first through reflective writing on text before it is considered in the classroom, next in a one page essay at the end of the week and finally through a final essay at the end of the term. Students are encouraged to relate to the text in their reflective writing and critiques in the manner of a hermeneutical circle. Students are further scaffolded in writing their final essay by the use of student reviewers. This study explored how the course dossier method is perceived and accomplished by students in a course for non-science students and in an upper-level physics course. It is found that students’ understanding of concepts improves as the course progresses.
        Speaker: Calvin Kalman (Concordia University)
      • 483
        Utilizing Reflective Writing in Introductory Physics Labatorials: Students Perspectives of Reflective Writing to Explore Science Textbooks
        The language of science is a language that scientists use to talk about nature. Students are not familiar with this language and as a result they have great difficulty understanding scientific texts. Students trend to memorize the materials that they see in the textbook without thinking about their meaning, because they believe that language and words hold the knowledge and they need to use the same words and terms in order to show their understanding. Such students who think that knowledge in science is a body of settled facts that comes from authority take a passive role in learning and become a receiver of knowledge, while those who try to make sense of the science language and construct their own understanding by questioning the knowledge presented to them are more likely to develop reasoning and critical thinking skills. It is up to us as teachers to motivate students to think about the meaning of concepts rather than memorizing the terms and definitions. Having a hermeneutical approach to science helps students gain a deeper understanding of the meaning. To help students approach the science textbooks in the manner of hermeneutics, we use a writing activity called “reflective writing” in a new style of introductory physics labs called “labatorials” at Mount Royal University. This paper provides an introduction to utilizing the “reflective writing” activity in “labatorials” and I will discuss students’ perspectives on these activities. Interviews with students who completed the reflective writing assignments in the introductory physics labatorials as well as an analysis of students’ reflective writing assignments helped us find key aspects that make the reflective writing activity useful to the students. Keyword: Science. Interpretation. Hermeneutics. Reflective writing, Labatorials.
        Speaker: Ms Mandana (Mandy) Sobhanzadeh (Mount Royal University)
      • 484
        Investigation of PeerWise Technology Implementation to Promote Pedagogical Content Knowledge of Physics Teacher-Candidates: From Theory to Practice
        Questioning is a key physics teaching skill. It relies on teachers’ Pedagogical Content Knowledge (PCK) (Shulman, 1986) and willingness to engage students in inquiry. A number of technology-enhanced pedagogies that promote conceptual science questions’ use have been developed lately (Keller et al., 2007). One of the most common is Peer Instruction (Lasry, 2008; Mazur, 1997; Milner-Bolotin, 2004). It engages students in responding to conceptual multiple-choice questions using clickers, such as the distribution of students’ responses can be immediately displayed. Then the students are engaged in peer discussions, followed by the repeated vote on the same question (Kalman, Milner-Bolotin, & Antimirova, 2010). The success of this pedagogy depends on the use of pedagogically effective questions that elicit student conceptual difficulties (Beatty et al., 2008; Lee, Ding, Reay, & Bao, 2011). This study aims to investigate the development of conceptual question design skills in physics Teacher-Candidates and the impact of this process on teacher-candidates’ PCK through the implementation of PeerWise collaborative design tool (Bates & Calloway, 2013; Denny, Luxton-Reilly, & Simon, 2009; Milner-Bolotin, 2014) during the 13-week long Physics Methods course.
        Speaker: Dr Marina Milner-Bolotin (The University of British Columbia)
        Slides
      • 485
        Flipping a graduate level course on Modern Electrodynamics
        Based on the findings from decades of Physics Education research (PER), many physics instructors today use student-centered teaching methods to support active or inquiry based learning. One method that is getting increasingly popular is the flipped classroom, where students watch the “lecture” on video, at their own pace, and use the valuable class time to work on problems together. For graduate students, however, classes are typically taught in a traditional lecture style, perhaps because it is assumed that they have the motivation and skills to learn from a lecture and do not need extra “support”. Even if this is true, we suspect that the lecture-only model does not make the best use of class time and is not the most efficient method to support student learning. Therefore, one of us (SJD) decided to flip his graduate level Electrodynamics class (with readings and pre-class questions instead of videos), the other (DA) observed and collected feedback from students and the instructor. The findings were used to improve the ongoing course, a method often called “action research” or “reflective practice”. We will present how the course was first designed, including the goals and the findings from PER that shaped the decisions. Then, we will share selected feedback – some anticipated, much of it surprising - and how it was used to iteratively improve the course. We find the results to be valuable not only for this course, but for teaching grad students in general, and will conclude with some suggestions for good practices for this audience.
        Speaker: Daria Ahrensmeier (Simon Fraser University)
      • 486
        Panel Discussion
    • Health Break (with exhibitors) / Pause santé (avec exposants) CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • R-MEDAL CAP Medal Talk - Pierre Savard, U. Toronto / TRIUMF (CAP-TRIUMF Vogt Medal Recipient/Récipiendaire de la médaille Vogt de l'ACP-TRIUMF) CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Robert Fedosejevs (University of Alberta)
      • 487
        The Higgs Boson, 3 years after the discovery
        In July of 2012, the discovery of a new particle consistent with the Standard Model Higgs boson was announced. Following the discovery, additional data were collected and the experiments improved the calibration of the detectors and their analysis techniques. In this talk, I will present an updated description of our understanding of the Higgs boson and discuss future research plans as the Large Hadron Collider begins its second run at a higher energy.
        Speaker: Pierre Savard (University of Toronto (CA))
    • Outreach "Tête-à-tête Liaisons externes CCIS 4-285

      CCIS 4-285

      University of Alberta

      Convener: Francine Ford (Canadian Association of Physicists)
    • R-PLEN Plenary Session - Francis Halzen, IceCube and Univ. of Wisonsin-Madison - Session plénière - Francis Halzen, IceCube and Univ. de Wisonsin-Madison CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Jean-Francois Arguin (Universite de Montreal (CA))
      • 488
        IceCube and the Discovery of High-Energy Cosmic Neutrinos
        The IceCube project has transformed one cubic kilometer of natural Antarctic ice into a neutrino detector. The instrument detects 100,000 neutrinos per year in the GeV to PeV energy range. Among those, we have recently isolated a flux of high-energy cosmic neutrinos. I will discuss the instrument, the analysis of the data, and the significance of the discovery of cosmic neutrinos.
        Speaker: Francis Halzen (High Energy Physics-Department of Physics-University of Wiscons)
    • DHP Annual Meeting / Assemblée annuelle DHP CCIS L1-029

      CCIS L1-029

      University of Alberta

      Convener: Jean Barrette (McGill University)
    • DTP Annual Meeting / Assemblée annuelle DPT CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Arundhati Dasgupta (University of Lethbridge)
    • Lunch / Dîner
    • PPD Annual Meeting / Assemblée annuelle PPD CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: Jean-Francois Arguin (Universite de Montreal (CA))
      • 489
        Status report
        Speaker: Jean-Francois Arguin (Universite de Montreal (CA))
        Slides
    • R2-1 Optomechanics - minisymposium II (DCMMP-DAMOPC) / Optomécanique - minisymposium II (DPMCM-DPAMPC) CCIS L2-200

      CCIS L2-200

      University of Alberta

      Convener: Giovanni Fanchini (The University of Western Ontario)
      • 490
        Optomechanics in a Millikelvin Environment: Towards QND Measurements
        It is well known that objects containing many atoms, such as superfluids and superconductors, can behave quantum mechanically when each particle occupies the same ground state. But can large objects demonstrate collective quantum behavior even when their constituent particles do not? For example, can a nanomechanical resonator be coaxed into a ground state of a vibrational degree of freedom? In this talk, I will discuss our progress towards the goal of demonstrating quantum nondemolition measurements of a nanomechanical resonator. In particular, we have developed an optomechanical measurement system based on tapered optical fibers that operates on the baseplate of our dilution refrigerator at 9 mK. Our intent is to demonstrate ground state occupation via quantum jump spectroscopy of the energy of such a quantum nanomechanical resonator.
        Speaker: John Davis (University of Alberta)
      • 491
        Applying nano-optomechanics to mass sensing
        The ultrasensitivity enabled by nano-optomechanical systems has rich potential from torque sensors able to see nanoscale magnet volumes to cantilever mass sensors able to weigh single large molecules. Mass sensitivity is determined from a combination of mechanical resonance sharpness (quality factor) and signal-to-noise ratio (SNR). With optomechanics, the signal readout technique is no longer the limiting factor to the latter – more fundamental noise sources become visible such as thermomechanical noise. By maximizing the SNR, sensitivity can even improve as quality factor falls. The implications of this are that mechanical resonators can remain ultrasensitive in ambient conditions where the resonance quality suffers due to fluid damping, and even in liquid environments. This opens up a host of sensing applications from gas chromatography to affinity bioassays, as well as many end-uses including environmental monitoring and microassay based disease diagnosis.
        Speaker: Wayne Hiebert (National Institute for Nanotechnology)
      • 492
        Optically-Defined Micromechanical Sensors
        In the field of optomechanics we have learned to use the forces exerted by laser light to gain a new level of control over a wide variety of mechanical systems, from kilogram-scale mirrors in gravitational wave detectors to nanomechanical elements in cryogenic environments. In this talk I will discuss how a very modest source of laser light (i.e. a few milliwatts) in an optical resonator can completely redefine the properties of an embedded micromechanical sensor. Since the behavior of photons in a cavity is fundamentally different from that of atoms in a flexible material, such systems should circumvent the limitations of the best existing materials and achieve an unprecedented level of force sensitivity. In the ultimate limit, we hope to essentially create ultrasensitive "microphones" capable of detecting (among other things) the quantum "hiss" of radiation pressure or the delicate superposition forces from a variety of qubits.
        Speaker: Jack Sankey (McGill University)
        Slides
    • R2-2 Strongly correlated systems (DCMMP) / Systèmes fortement corrélés (DPMCM) CCIS L1-140

      CCIS L1-140

      University of Alberta

      Convener: Jinshan Wu (Beijing Normal University)
      • 493
        What does localization mean in interacting systems?
        In 1958, Phil Anderson showed that the wavefunctions of noninteracting particles moving in a random potential can become localized in space. Anderson localization has since been observed in a wide variety of systems. However, interactions between particles aren’t always negligible. In fact it is precisely the materials in which electron-electron interactions are most significant that are of the greatest current interest. Moreover, the properties of these materials are usually tuned by doping, which introduces disorder. So how do interactions effect localization? This talk will provide an overview of recent progress towards clarifying what localization means in interacting systems.
        Speaker: Rachel Wortis (Trent University)
        Slides
      • 494
        An emergent phase transition as an organizing principle for strongly correlated superconductors
        Band theory and BCS theory are arguably the most successful theories of condensed matter. Yet, both of them fail miserably for high-temperature cuprate superconductors and layered organic superconductors. New theoretical methods are required. In this talk, I compare experiment in cuprates and layered organics with theoretical results obtained from extensions of dynamical mean-field theory for the Hubbard model. In the presence of electronic repulsion strong enough to lead to a Mott insulator at half-filling, both the normal state and the superconducting state are unusual. In the normal state, a first-order transition between a metal and a pseudogap emerges from the Mott insulator. That first-order transition ends at a critical point. In the supercritical region, a Widom line and its precursor determine the crossovers seen experimentally. We demonstrate that much or the phase diagram, including superconductivity, is controlled by this first-order transition, a finite-doping signature of the Mott transition. In this strongly correlated regime, the maximum Tc is not concomitant with an antiferromagnetic quantum critical point, contrary to what is sometimes observed, for example in heavy fermions.
        Speaker: Andre-Marie Tremblay (Universite de Sherbrooke)
      • 495
        Dynamic Hubbard model description os superconductivity
        Electrons in metals move around and they interact with one another via the Coulomb interaction. When electrons form extended (i.e. Bloch) states they do the same thing. Yet very often they form a collective exotic state like superconductivity. Is this the consequence of pairing via an attractive interaction, or is something more subtle at work? This talk will discuss what is currently not satisfactory in the "standard model" of superconductivity, and will briefly explain the physics of the Dynamic Hubbard model (DHM), which might remedy some of these deficiencies.
        Speaker: Prof. Frank Marsiglio (University of Alberta)
    • R2-3 **CANCELLED** Advanced Instrumentation at Major Science Facilities: Data Acquisition (DIMP) / **ANNULÉE** Instrumentation avancée dans des installations scientifiques majeures: données et applications (DPIM) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Kirk Michaelian (Natural Resources Canada)
    • R2-4 Curriculum Development and Revitalization (DPE) / Développement et revitalisation des programmes (DEP) CCIS L1-160

      CCIS L1-160

      University of Alberta

      Convener: Patricia Mitchler (Balmoral Hall School)
      • 496
        Launching the Canadian Institute of Physics Education Research (CIPhER)
        Physics education research (PER) is a blooming field with a widespread research agenda spanning through several orders of magnitude, from micro-cognitive processes happening in a few tens of milliseconds to the expertise achieved in 10 000+ hours. Although the number of PER researchers in Canada is growing along with the interest and demand from physics educators, individual PER researchers may be isolated both geographically and by the specific type of PER they conduct. The purpose of this talk is to present and launch a new initiative to connect PER researchers from across Canada and support collaborative multi-center funding applications and research projects. The Canadian Institute for Physics Education Research (CIPhER) is designed as a digital community of practice that facilitates the sharing of ideas, fosters collaboration and assists in the collection of data and the conducting of PER projects.
        Speaker: Nathaniel Lasry (John Abbott College)
      • 497
        The design, implementation and continuous improvement of "Introduction to Graduate Studies: Research and Teaching in Physics" at SFU
        When students start their graduate studies, they face new challenges: managing their time between course work, research and teaching, learning new skills such as reading research papers and writing research proposals, or dealing with difficult undergrads in their tutorial. Since all our new graduate students are affected by these issues to some degree, in 2012 the SFU Physics Department introduced a new mandatory course to not only handle the learning curve in a more efficient manner, but to also create a sense of community among the students coming to SFU from various parts of the world and to clarify the department’s expectations. We will present the course design and the ideas that shaped it. Then, we will show how we included student and instructor feedback in updating the course, with a focus on specific topics including structure and content of a journal article, teaching undergraduates, and research planning. The feedback we received over three iterations of the course illustrated how some topics are much harder to “teach” than others, and helped clarify some of our assumptions – perhaps misconceptions - about teaching graduate students.
        Speaker: Daria Ahrensmeier (Simon Fraser University)
      • 498
        The "PHAS Smart Exam" an attempt to improve the examination process of the multi-section intro physics course.
        There are many pedagogical and logistical challenges in the delivery of the large ~1000 student introductory physics course, for non-physics majors. Logistical challenges are best addressed with a little better planning and a lot more funding and manpower. The challenge of creating and administering an effective exam usually relies a little on funding and a lot on planning. This presentation describes the development of the 'PHAS Smart Exam'. It is a work in progress, but attempts to minimize marking variance that arises when a large team of TAs are involved, and streamlines the process using a secure online tool for markers developed in the Dept. of Physics and Astronomy.
        Speaker: Dr Philip Langill (University of Calgary)
      • 499
        Panel
    • Health Break / Pause santé CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • R3-1 Light-Matter Interactions (DAMOPC-DCMMP) / Interactions entre la lumière et la matière (DPAMPC-DPMCM) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Paul Barclay (University of Calgary)
      • 500
        Gold Nanostructures and Their Applications
        Nanostructured metallic surfaces support surface plasmon (SP) excitations. The resonance conditions depend on the optical properties at the metal-dielectric interface. For instance, the monitoring of the shift of the surface plasmon resonance (SPR) due to molecular adsorption events is a well-established approach in biosensing. The SPR condition also leads to an increase in the electric field at the surface which can be explored for enhanced spectroscopy schemes, such as surface-enhanced Raman scattering (SERS). In this presentation, I will provide an overview of the recent advances from our group on the fabrication of metallic nanostructures, and discuss some of their applications.
        Speaker: Prof. Alexandre Brolo (University of Victoria)
      • 501
        Superfluid $^4$He Helmoltz nanoresonator
        We have built and investigated the properties of a nanofluidic Helmoltz resonator operating with superfluid $^4$He. The density oscillations of the fluid are measured with an on-chip capacitor, allowing us to probe a small volume of helium contained in the resonator. Oscillators based on superfluid $^4$He are expected to reach high quality factors due to its high purity and dissipationless flow. We have identified and studied the several dissipation mechanisms responsible for the limitation of the Q-factor in our device. Different improvements are proposed to reach higher Q-factors.
        Speaker: Fabien Souris (University of Alberta)
      • 502
        Torque Magnetometry of an Individual Aggregate of ~350 Nanoparticles
        Magnetic properties for isolated and small-scale assemblies of nanoparticles are generally derived from measurements of bulk nanoparticle systems. To complement this, we aim to investigate these properties for individual assemblies of single-domain magnetite nanoparticles. Nanoparticles, ~ 50 nm in size and harvested from magnetotactic bacteria, were deposited by Nano eNnabler (BioForce Nanosciences TM) on a 100 nm thick, high stress Si3N4 membrane 40 × 200 μm in size. The nanoparticles form diverse patterns on the membrane, including aggregates influenced by dipolar coupling. To capture select structures for measurement, nanomechanical torsional resonators are fabricated in the membrane by direct writing with a focused ion beam. Magnetic measurements are obtained by nanomechanical torque magnetometry, a sensitive method to probe the quasi-static magnetization response. The observations are compared to micromagnetic modeling of the hysteresis of a specific measured cluster of ~ 350 nanoparticles, and to numerical simulations of the mechanical modes.
        Speaker: Tayyaba Firdous (Department of Physics, University of Alberta, T6G 2E1, Canada)
      • 503
        Interdisciplinary Applications of Optical Spectroscopy on a Laser-Induced Plasma
        When a short pulse of laser light is focused to a small spot, the energy density may be high enough to ablate and partially ionize whatever material was in the focal volume of the laser (whether it was a solid, liquid, or gas.) This ionized gas plume can strongly interact with the incident laser pulse, quickly leading to significant heating and further ionizations, resulting in a high-temperature (50,000 K) micro-plasma, or “laser-induced plasma.” As this plasma expands and cools over the course of microseconds following the laser pulse, element-specific spontaneous emission is emitted from the atoms that were present in the target material. A careful time-resolved spectroscopy of this spontaneous emission allows the quantification of the elements that were present in the target, a qualitative assay of the relative concentrations of a number of elements present in the target, and also provides a diagnostic of the plasma’s time-dependent temperature and electron density. In this talk, I will introduce the physics of this process and describe the current open questions and areas of investigation. I will also describe our group’s efforts to use this real-time diagnostic assay of an analytic laser-induced plasma as a tool to rapidly identify pathogenic bacteria by measuring their elemental content; as a source of highly-excited atoms and ions for atomic physics measurements on elements of astronomical interest; and as a real-time diagnostic in a variety of other biomedical applications. Lastly, I will introduce the use of this technology on the Mars Science Laboratory rover “Curiosity” where it provides the underlying technology for the mission-critical ChemCam mast unit.
        Speaker: Steven Rehse (University of Windsor)
    • R3-2 Polymers and Biopolymers (DCMMP-DMBP) / Polymères et biopolymères (DPMCM-DPMB) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: Melanie Martin (University of Winnipeg)
      • 504
        Plasticity in amorphous solids
        Yielding and the slow plastic flow of amorphous solids exhibit striking heterogeneities: swift localised particle rearrangements take place in the midst of a more or less homogeneously deforming medium. At low temperatures, failure events become increasingly correlated and develop self-similar properties that resemble critical phenomena. Moreover, plastically deforming regions organize into macrocroscopic shear bands that limit the lifetime to failure. This talk will discuss two questions that must form essential ingredients in a statistical theory of amorphous plasticity: where to localized plastic events occur, and how do correlations arise from their interactions? With molecular dynamics simulations of model athermal solids driven by shear at constant strain rate, we first show that the loci and directions of local shear transformations can be predicted from a superposition of soft modes in the low energy vibrational spectrum [1]. The so-defined "soft spots" are long-lived structural features and remain correlated with plastic activity even in the supercooled fluid regime. We then compute spatiotemporal correlations of the plastic events and compare them to a mesoscale elastoplastic model that coarse-grains the atomistic dynamics into a lattice model that preserves only the essential features of the localized plastic events. Upon local yielding, energy is redistributed throughout the lattice with an elastic Green’s function that displays quadrupolar symmetry and algebraic decay. We test several assumptions in the mesoscopic theory directly against the behaviour on the molecular level [2,3]. Recent successes as well as avenues for further improvement of these class of models will be discussed. [1] S. S. Schoenholz, A. J. Liu, R. A. Riggleman, J. Rottler, Physical Review X 4, 031014 (2014). [2] F. Puosi, J. Rottler, J. L. Barrat, Phys. Rev. E 89, 042302 (2014). [3] A. Nicolas, J. Rottler, J-L. Barrat, The European Physical Journal E 37, 1 (2014).
        Speaker: Joerg Rottler (UBC)
      • 505
        Getting into that "Room at the Bottom" of DNA Analysis using Tunable Nanoscale Confinement
        A wide range of life-preserving processes, such as DNA transcription and repair, rely on weak intermolecular interactions and slow dynamics which occur at high concentrations, over long time periods, and often under confinement. Visualizing dynamic processes can present a challenge to fluorescence microscopy, the work horse for resolving biological processes at the molecular scale. To address this challenge, we present new in vitro diagnostics which use tunable and transverse nanoscale confinement to bring biomolecules into crisp view under previously inaccessible conditions, approaching those in the human body. We tackle the challenge of manipulating and visualizing long strands of DNA for genomic analysis, ultimately extracted from single cells (Berard et al, PNAS 2014 and Commentary). Further, we develop nanoscale spectroscopy methods to establish how conformational DNA fluctuations regulate transcription and gene expression, which remains an open and compelling question.
        Speaker: Sabrina Leslie (McGill University)
      • 506
        Multiscale modeling of multifunctional, hybrid and nanomaterials: from quantum chemical and microscopic to coarse-grained level with an effective pair potential
        The steady increase in the complexity of new industrial materials and the need to accurately predict their properties have resulted in rapid development of sophisticated methods of modelling on multiple length and time scales. A simple hierarchical approach combines different methods for different scales (quantum mechanical, microscopic, mesoscopic) interpreted independently. Information obtained at one level is transmitted to the next level without critical assessment or performance improvement. An advanced hierarchical approach works in a similar manner but with a feedback control. In these approaches, continuous (macro- and mesoscale) properties of materials stem from and can be controlled with their microscopic structure. To connect to large scales, molecular models representing microscopic structure must be coarse-grained to reduce detailed degrees of freedom while preserving relevant ones. The industrial importance of coarse-graining techniques to connect multiple length and time scales and to properly take into account the most notable mesoscale phenomena is increasingly appreciated. When implemented in software packages, such modelling techniques significantly accelerate development of new materials satisfying modern industrial requirements. In this contribution, we present and discuss a hierarchical procedure of bridging the gap between atomistic and macroscopic modelling through mesoscopic level of description. Its successful application is demonstrated on examples of multi-scale modelling and synthesis of polyester ionomers, to explain gelation mechanism and prefigure gelation ability of oligomeric electrolyte gelators, and to predict both structural and dynamic properties of polymer solutions with high accuracy and computational efficiency. To this end, we develop a new methodology which replaces the heuristically defined interaction potential in dissipative particle dynamics (DPD) with an effective pair potential obtained using molecular theory of solvation, and validate the method on a well-studied real system. The methodology is free from artificial restrictions on potential range and shape and also eliminates solvent from DPD, which enormously increases computational efficiency.
        Speaker: Alexander E. Kobryn (National Institute for Nanotechnology)
      • 507
        Quantitative metrics for assessing positional and orientational order in colloidal crystals
        Structural control in colloidal films has potential benefits for photonics, material templating, and in fundamental studies of phase transitions. Although there are numerous self-assembly techniques to prepare colloidal crystals, there is great variability in the methods used to characterize order and disorder in these materials. In this work, we take on the task of assessing different kinds of structural order from two-dimensional microscopy images of colloidal crystals produced by many common methods (and by many different research groups) including spin-coating, dip-coating, convective assembly, electrophoretic assembly, and sedimentation. To do this, we use a suite of analysis methods that includes measures for both positional and orientational orders. Our benchmarks are two-dimensional lattices that we simulated with different degrees of controlled disorder. We find that translational measures are adequate for characterizing small deviations from perfect order, while orientational measures are more informative for polycrystalline and highly disordered crystals. Our analysis codes are freely available for others to use, and they offer a convenient and unified strategy for comparing structural order among different colloidal crystals.
        Speaker: Kristin Poduska (Memorial University of Newfoundland)
    • R3-3 Advanced Instrumentation at Major Science Facilities: Data and Applications (DIMP) / Instrumentation avancée dans des installations scientifiques majeures: acquisition de données (DPIM) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Kirk Michaelian (Natural Resources Canada)
      • 508
        Review of the recent progress at the Advanced Laser Light Source facility and applications
        The ultrafast laser technology is evolving toward higher peak and average power and shorter pulse. I will review the world wide effort in this sector and present some technologies that have been recently, or will be soon, integrated at ALLS to achieve very high peak power. The roadmaps for some laser-based machines targeting application of x-ray imaging and particle acceleration in medical and industrial sectors will be discussed.
        Speaker: Jean-Claude KIEFFER (EMT-INRS)
      • 509
        Advanced Instrumentation at the Canadian Neutron Beam Centre
        Because of the unique way that neutrons interact with matter, neutron scattering methods provide knowledge about materials that often complements the insights provided by other instruments or techniques and that sometimes reveals information that is very difficult or impossible to obtain otherwise. Located at the NRU research reactor, within the Chalk River site of Canadian Nuclear Laboratories, the Canadian Neutron Beam Centre (CNBC) provides access, for researchers from academia, industry and government labs, to a suite of neutron-beam instruments and methods for probing structures and dynamics of materials over a wide range of scales. This presentation will introduce recent advancements of instrumentation at the CNBC, enabling condensed-matter scientists to explore how materials respond to applied fields, loads, temperatures and other conditions that are relevant to fundamental understanding and applications to technology. Examples will illustrate new capabilities to support research in magnetism, biophysics and materials science.
        Speaker: John Root (Canadian Nuclear Laboratories)
    • CEWIP Annual Meeting & Reception / Assemblée annuelle CEFEP et réception CCIS L1-047

      CCIS L1-047

      University of Alberta

      Convener: Shohini Ghose (urn:Facebook)
    • Recognition Reception at the Art Gallery / Réception de reconnaissance à la Art Gallery Art Gallery

      Art Gallery

    • F1-1 Networks and complex systems (DCMMP) / Réseaux et systèmes complexes (DPMCM) CCIS 1-140

      CCIS 1-140

      University of Alberta

      Convener: Mona Berciu (University of British Columbia)
      • 510
        Which Subfield of Physics is More Influential?
        In this talk, I will try to answer two questions about physics: First, how important is each subfield and second, how does a specific subfield influence other subfields? We modify the well-known open-system Leontief Input-Output Analysis in economics into a closed-system analysis focusing on eigenvalues and eigenvectors and the effects of removing one subfield. We apply this method to the subfields of physics. This analysis has yielded some promising results for identifying important subfields (for example the field of statistical physics has large influence while it is not among the largest subfields) and describing their influences on each other (for example the subfield of mechanical control of atoms is not among the largest subfields cited by quantum mechanics, but our analysis suggests that these fields are strongly connected). This method is potentially applicable to more general systems that have input-output relations among their elements.
        Speaker: Jinshan Wu (Beijing Normal University)
      • 511
        Probing helium mass flow through a solid-liquid-solid double Junction
        Recent experiments by Hallock and coworkers [1] observed mass transport through solid $^4$He and suggested it was due to flow along dislocation lines. In those measurements, helium was injected and removed through Vycor “electrodes” filled with superfluid $^4$He. Here, we report the results of a related experiment: a Vycor rod filled with superfluid $^4$He is sandwiched between two bulk solid regions. By compressing solid $^4$He on one side and measuring pressure changes on the other, we can detect flow through the Vycor, without necessarily having flow through the solid. In high pressure crystals we saw no flow below 1 K but in samples below 28 bar we observed flow down to the lowest temperatures (below 20 mK). The temperature dependence of this flow was very similar to that of the flow seen in previous experiments [1]: it began around 600 mK, increased as the temperature was reduced, then decreased dramatically at a temperature which depended on $^3$He impurity concentration (around 75 mK for standard isotopic purity samples). We suggest that flow in solid $^4$He experiments is limited by mass transfer through the solid-liquid interface at the Vycor ends. This project is funded by NSERC Canada and by ERC (AdG 247258-SUPERSOLID). [1] Phys. Rev. Lett. 105 145301 (2010); Phys. Rev. Lett. 113, 035302 (2014).
        Speaker: Dr Zhigang Cheng (University of Alberta)
      • 512
        (tba)
        Speaker: Prof. Xiaosong Chen (Institute of Theoretical Physics, China Academy of Science)
    • F1-2 Experimental Advances and Accelerators (DNP-DIMP-PPD) / Progrès expérimentaux et accélérateurs (DPN-DPIM-PPD) CCIS 1-160

      CCIS 1-160

      University of Alberta

      Convener: Zisis Papandreou (University of Regina)
      • 513
        TRIUMF ARIEL Electron Linear Accelerator
        Hosted by TRIUMF, supported by a consortium of 14 Canadian Universities led by the U.Victoria, and funded by the Canadian Foundation for Innovation, the National Research Council and the province of British Columbia, the ARIEL project commenced design and construction of the ARIEL buildings and the 50 MeV, 10 mA capable electron linear accelerator (e-linac) in September 2010. The accelerator, which uses super-conducting radio-frequency cavities operating at 1.3GHz at 2K, is designed for 100% duty factor operation. The focus of this report is the e-linac major systems, a summary of the accelerator capability, and high lights from the low power commissioning in 2014. In addition, plans for the build out of the electron beamline to the target station for production of radioactive ion beams, and the future upgrade of the accelerator will be presented.
        Speaker: Shane Koscielniak (TRIUMF)
      • 514
        ARIEL: Driving Scientific Discovery and Innovation with TRIUMF's Advanced Rare Isotope Laboratory
        TRIUMF has embarked on the construction of ARIEL, the Advanced Rare IsotopE Laboratory, with the goal to substantially expand TRIUMF’s existing capabilities in rare isotope production and utilization for nuclear physics and astrophysics, materials science and health science. ARIEL will use proton-induced spallation and electron-driven photo-fission of ISOL targets for the production of short-lived rare isotopes that are delivered to experiments at ISAC. The first stage of ARIEL, completed on time in 2014, consists of a state-of-the-art 25 MeV, 100 kW superconducting radio-frequency electron linear accelerator and the ARIEL building. Supported by 19 Canadian universities, ARIEL-II, the next stage of ARIEL, will add new isotope production and delivery systems to begin a broad program of up to 3 simultaneous experiments with a wide variety of exotic isotope species that will significantly increase both the scientific productivity and impact of TRIUMF’s rare isotope program. ARIEL-II will develop the next generation of medical isotopes for novel imaging applications and targeted alpha therapy of tumours. In addition, ARIEL-II will further Canadian industry’s mastery of SRF accelerator technology, the technology of choice for modern particle accelerators. The project is organized in five phases designed to interleave science and construction to ensure a continuous stream of scientific results while new capabilities are brought on line. I will present an overview of the ARIEL project, and discuss the phases, technical challenges, capabilities, science objectives, and timeline.
        Speaker: Dr Lia Merminga (TRIUMF)
    • F1-3 Biomedical Optics and Biophotonics (DAMOPC-DIAP-DMBP) / Optique biomédicale et biophotonique (DPAMPC-DPIA-DPMB) NINT Taylor room

      NINT Taylor room

      University of Alberta

      Convener: Melanie Campbell (University of Waterloo)
      • 515
        The Physics of X-ray Tomography: Not as simple as it looks
        Computed tomography (CT) is an inverse problem in which an image is reconstructed from measurements, making use of the forward problem presented by the well-known Beer-Lambert Law for the absorption of a beam of monochromatic radiation. Then, the natural logarithm of the relative intensity of a transmitted beam of radiation leads to a linear problem in the form of a Radon transform, the inverse of which results in the reconstruction of a tomograph. Inversion is typically performed using filtered backprojection, making use of the Fourier Slice Theorem, but other inversion methods are also utilized. However, the implication of relying on the simplistic forward-problem formulation of the Beer-Lambert Law, to facilitate mathematical inversion, is fraught with significant physical implications, particularly when exact quantifiable image attributes are needed. This presentation will examine the physical aspects of forward modelling not accounted for in the inversion process and their impact on exact imaging, with attention to tomography with x-rays.
        Speaker: Esam Hussein (University of Regina)
        Slides
      • 516
        Computational modeling of Plasmon coupled gold nanoparticles for biomedical applications
        There has been a recent increase in the use plasmonic nanoparticles for biomedical applications, such photo-thermal therapy, optical and optoacoustic imaging, and biosensors. Gold nanoparticles (GNPs) are of particular interest due to their strong plasmon resonances, stability and biocompatibility. Plasmon coupling occurs when GNPs aggregate resulting in a shift of the resonance wavelength. GNPs can be designed to self-assemble under certain biological conditions such as low PhD or elevated temperature. Aggregation can also occur when GNPs are endocytosed and compartmentalized in intracellular vesicles. Coating GNPs with peptides that cause them to bind to cell surface receptors, a process known as receptor-mediated endocytosis, enables this. Therefore the optical behavior of GNPs ensembles can be sensitive to biological conditions, opening up a large possibility of new medical imaging modalities and therapies. The presentation will outline a finite element method based computational model of the optical behavior of GNPs that includes plasmon coupling. The model has been used to study the application of plasmon coupled GNPs for several biomedical applications. The results from some of these studies will be presented.
        Speaker: Carl Kumaradas (Ryerson University)
      • 517
        Detection of Trace Gases using Fiber Laser Technology- Part 1
        Fiber-optic sensors based on fiber Bragg gratings have been established as rugged and reliable devices and have found applications in environmental monitoring, oil and gas reservoir monitoring, and in performing temperature, pressure, and strain measurements. However, new sensors with higher sensitivity, greater accuracy, and a simpler design, using fiber laser technology, would provide significant cost benefits and performance to the end user. The authors have developed a device, based on fiber laser technology, to detect trace gases. An erbium-doped fiber was used as the gain medium. For the collection and detection of trace gases, a gas cell was used inside the laser cavity. The authors will present the structure of the device and its working principle. The device was very sensitive and could detect gas at very low levels. The research work is supported financially by Natural Sciences and Engineering Research Council of Canada and Agrium, Canada.
        Speaker: Gautam Das (Lakehead Uniersity)
    • (F-PLEN1) - CAP Best Student Presentations Final Competition / Session plénière - Compétition finale de l'ACP pour les meilleures communications étudiantes CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Richard MacKenzie (U. Montréal)
    • Health Break / Pause santé CCIS L2 Foyer

      CCIS L2 Foyer

      University of Alberta

    • F-PLEN1 CAP Best Student Presentations Final Competition / Compétition finale de l'ACP pour les meilleures communications étudiantes CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Richard MacKenzie (U. Montréal)
    • F-PLEN2 Plenary Session - David A. Weitz, SEAS Harvard / Session plénière - David A. Weitz, SEAS Harvard CCIS L2-190

      CCIS L2-190

      University of Alberta

      Conveners: Adam Sarty (Saint Mary's University), Maikel Rheinstadter (McMaster University)
      • 518
        Cell Stiffness and Cell Volume
        The stiffness of cells is commonly assumed to depend on the stiffness of their surrounding: bone cells are much stiffer than neurons, and each exists in surrounding tissue that matches the cell stiffness. In this talk, I will discuss new measurements of cell stiffness, and show that cell stiffness is strongly correlated to cell volume. This affects both the mechanics and the gene expression in the cell, and even impacts on the differentiation of stem cells.
        Speaker: Prof. David A. Weitz (SEAS Harvard)
    • (F-PLEN3) Announcement of Winner, CAP Best Student Presentation and Close of Conference / L'annonce du gagnant(e) compétition meilleure communication étudiante de l'ACP, Clôture du Congrès CCIS L2-190

      CCIS L2-190

      University of Alberta

      Convener: Richard MacKenzie (U. Montréal)
    • CAP Board Meeting (New and Old) / Réunion du CA de l'ACP (nouveau et ancien) CCIS L1-047

      CCIS L1-047

      University of Alberta

    • Meeting of Local Organizing Committees 2015, 2016 + / Réunion des comites organisateurs locaux 2015, 2016 + CCIS L1-047

      CCIS L1-047

      University of Alberta