2016 CAP Congress / Congrès de l'ACP 2016

America/Toronto
University of Ottawa

University of Ottawa

SITE Building, 800 King Edward Ave, Ottawa, ON
Description

CAP BEST STUDENT PAPER COMPETITION 

Results of the 2016 CAP Best Student Paper Competition (Divisions and CAP overall, oral and poster)

Congratulations! If you haven't received your prize confirmation letter at the Recognition Gala, June 16, please contact Danielle at capmgr@uottawa.ca.

Click on the "Timetable" on the left to view the Congress program.

The 2016 CAP Congress is being hosted by the University of Ottawa (Ottawa, ON), June 13-17, 2016. 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/2016 ) for easy access to updates and program information.


Compétition de la meilleure communication étudiante de l'ACP

 

Résultats de la Compétition de la meilleure communication étudiante de l'ACP 2016 (de divisions et globale de l'ACP, orale et affiche)

Félicitations! Si vous n'avez pas reçu votre lettre de confirmation de prix au Gala de reconnaissance du 16 juin, veuillez communiquer avec Danielle au capmgr@uottawa.ca

Cliquez sur "Timetable" à gauche pour voir la programmation du Congrès.

Le Congrès 2016 de l'ACP se tiendra à l'Université d'Ottawa (Ottawa, ON) du 13 au 17 juin 2016 (des réunions de l'IPP, l'IPCN et du conseil de l'ACP auront lieu le dimanche 12 juin). 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/congres/2016) pour accéder facilement aux mises à jour et au contenu de la programmation.

    • 8:00 AM 12:00 PM
      **CANCELLED / ANNULÉ** IPP Town Hall I / Consultation publique de l'IPP I Colonel By C03

      Colonel By C03

      University of Ottawa

      Convener: Michael Roney (University of Victoria)
    • 12:30 PM 5:00 PM
      CAP Advisory Council (Old and New) / Conseil consultatif de l'ACP (ancien et nouveau) FSS 4004

      FSS 4004

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
    • 1:30 PM 4:15 PM
      Joint CINP-IPP Meeting / Réunion conjointe de l'ICPN et de l'IPP (DPN-PPD) Colonel By C03

      Colonel By C03

      University of Ottawa

      Conveners: Prof. Garth Huber (University of Regina), Michael Roney (University of Victoria)
    • 4:15 PM 4:30 PM
      Health Break / Pause santé
    • 4:30 PM 7:00 PM
      CINP AGM & Board Meeting / Réunion du conseil et AGA de l'ICPN Colonel By D103

      Colonel By D103

      University of Ottawa

      Convener: Prof. Garth Huber (University of Regina)
    • 4:30 PM 6:15 PM
      IPP AGM / AGA de l'IPP Colonel By C03

      Colonel By C03

      University of Ottawa

      Convener: Michael Roney (University of Victoria)
    • 5:00 PM 8:30 PM
      **CANCELLED / ANNULÉ** CAP Board Dinner Meeting: CAP Board Dinner Meeting FSS 4004

      FSS 4004

      University of Ottawa

    • 7:30 PM 9:30 PM
      IPP Inst. Members and Board of Trustees Meetings / Réunions des membres inst. et du conseil de l'IPP Colonel By D103

      Colonel By D103

      University of Ottawa

      Convener: Michael Roney (University of Victoria)
    • 8:00 AM 9:35 AM
      IPP Town Hall II / Consultation publique de l'IPP II Colonel By C03

      Colonel By C03

      University of Ottawa

      Convener: Michael Roney (University of Victoria)
    • 9:30 AM 10:20 AM
      M-PLEN Plenary Session - Start of Conference - Hendrik Schatz, Michigan State Univ./NSCL / Session plénière - Ouverture du Congrès - Hendrik Schatz, Michigan State Univ. / NSCL Marion 150

      Marion 150

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
      • 9:30 AM
        Nuclear Astrophysics with Radioactive Beams 50m
        Stellar explosions and colliding neutron stars are important sources of the chemical elements in nature. The properties of very unstable isotopes that are created for fleeting moments in these extreme astrophysical sites, imprint themselves onto the nature of the explosion and the characteristic element patterns that are created and ultimately shape the composition of the visible universe. Accelerator facilities that produce beams of these short lived radioactive isotopes can now be used to study the relevant nuclear reaction rates and nuclear properties so one can understand in the laboratory how stars create elements. This also opens the door to using observed element patterns as a diagnostic tool to peek into the deep interiors of some of the most extreme stellar sites. I will review some of the current open questions related to astrophysical processes with unstable nuclei, and how experiments at current and planned rare isotope facilities in the US, Canada, and elsewhere, in concert with observations and astrophysical models, are addressing these questions.
        Speaker: Hendrik Schatz (National Superconducting Cyclotron Laboratory)
    • 10:30 AM 12:00 PM
      M1-1 Newish-faculty Workshop: So You Think You Can Teach Physics! (DPE) / Atelier pour nouveaux professeurs : vous pensez pouvoir enseigner la physique! (DEP) Colonel By D103

      Colonel By D103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Calvin Kalman (Concordia University)
    • 10:30 AM 12:00 PM
      M1-2 Material Growth and Processing (DCMMP) / Croissance et traitement des matériaux (DPMCM) Colonel By B205

      Colonel By B205

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Prof. Mohamed Siaj (UQAM)
      • 10:30 AM
        Upconverting and Near-Infrared Emitting Nanoparticles: From Synthetic Strategies to Potential Applications 30m
        Lanthanide-based nanostructures are well known for their outstanding optical properties that are based on the electronic configuration of the trivalent lanthanide ions (Ln3+), which is characterized by an incompletely filled 4f shell, located inside the complete 5s2 and 5p6 shells. This results in a shielding of valence electrons, which are therefore only weakly affected by the environment. Consequently, when doped in appropriate host materials, the influence of the host lattice on the optical transitions within the 4f configuration is small, and narrow optical absorption and emission bands as well as long lifetimes of the excited electronic states of the Ln3+ are obtained. Following a stepwise excitation with near-infrared (NIR, typically 980 nm) light, Ln3+-doped nanostructures show upconversion (ultraviolet, visible and NIR light) emission. In addition, NIR light of longer wavelengths (> 1000 nm) can be emitted under excitation with NIR light when appropriate Ln3+ dopants are chosen (e. g., Er3+ or Ho3+). Based on this, Ln3+-doped nanostructures have been suggested for a whole gamut of applications including the field of bioimaging and sensing. Fluorides, such as NaGd4, NaYF4 or LiYF4, are commonly considered as suitable host materials and their preparation via the thermal decomposition process has been widely studied. Alternatively, oxides, such as Gd2O3 or Y2O3, have been suggested as host materials for Ln3+ ions resulting in upconverting and NIR emitting nanostructures. Ln3+-doped oxides of various sizes and shapes (nanoparticles, nanorods) can for instance be obtained by precipitation or solvothermal approaches. In this presentation, various synthetic strategies leading to upconverting and NIR emitting Ln3+-doped nanostructures will be discussed, and their application of the resultant materials in optical bioimaging and nanothermometry will be presented.
        Speaker: Prof. Eva Hemmer (University of Ottawa)
      • 11:00 AM
        Custom low-dimensional material systems explored from atom to bulk 30m
        The ability to controllably layer atomically thin crystals into custom-made materials holds promise for realizing physical systems with distinct properties, previously inaccessible. The experimental results described in this talk seek to uncover the unique nature of the charge carriers in such few-atoms-thick materials as well as effects that interlayer coupling and disorder have on their properties. In the first part of the talk I will discuss scanning tunneling microscopy (STM) and spectroscopy (STS) experiments performed on graphene systems at low temperatures and in magnetic field. We find that twisting graphene layers away from the equilibrium Bernal stacking leads to the formation of Moiré patterns and results in a system with novel electronic properties tuned by the twist angle. Moreover, we study Landau quantization in graphene and by performing spatially resolved STM/STS we demonstrate the true discrete quantum mechanical electronic spectrum within the Landau level band near an impurity in graphene in the quantum Hall regime. In the second part of the talk I will focus on the 1T polymorph of TaS2, which has one of the richest phase diagrams among the layered transition metal dichalcogenides. We address the question of how the transition from bulk to few layers affects the different phases in this material. Specifically, we use variable temperature Raman spectroscopy measurements and show that the existence of the most highly ordered phases depend on having a critical number of stacked 1T-TaS2 layers. Furthermore, using low temperature STM/STS, we explore the spatial variation of the electronic properties of the commensurate charge density wave phase at the atomic level.
        Speaker: Prof. Adina Luican-Mayer (University of Ottawa)
      • 11:30 AM
        Atomic Force Microscopy Study of the Effect of Poly(aspartic acid) on Calcium Oxalate 15m
        Kidney stone disease is a urological disorder that affects 10% of the human population, resulting in considerable pain and potential renal failure. It is known that certain macromolecules, such as osteopontin (OPN), can limit the formation of calcium oxalate monohydrate (COM) crystals, the major constituent of kidney stones. An explanation for this effect is provided by the Cabrera-Vermilyea (C-V) model, which proposes that trace amounts of adsorbed impurities can pin growth steps, forcing them to curve, thereby reducing the effective supersaturation. This “kinetic inhibition” is distinct from the well-known freezing-point depression, in which the thermodynamic phase diagram is altered by the presence of impurities. However, microscopic evidence for the C-V model is limited. We have been using the atomic force microscope (AFM) to investigate COM crystallization in situ in the presence of OPN, peptides derived from OPN, and synthetic macromolecules such as poly(aspartic acid) (poly-ASP). The presence of poly-ASP causes a rapid change in growth-step morphology and drastically slows the growth. At low poly-ASP concentrations, we see a dependence on crystallographic direction, with one direction displaying strong pinning while others continue to grow. This results in “finger-like” features at a threshold concentration that depends strongly on the polymer length. In this talk, we model these growth features using inhibitor diffusion, adsorption to growth steps, and incorporation into the growing crystal. An understanding of the microscopic details of calcium oxalate crystallization is not only important for the development of potential therapies for kidney stone disease, but will also provide insights into the inhibition mechanism that will be transferable to other natural and commercial crystallization systems.
        Speaker: Ms Himasha Wijesekara (University of Western Ontario)
      • 11:45 AM
        Maximizing electrophoretic mobility differences among polymorphic materials 15m
        Physical separation of different polymorphs is a serious experimental challenge, but success would help efforts in applications as diverse as drug discovery, environmental remediation, and cultural conservation. To meet this challenge, we demonstrate a proof-of-principle method to separate polymorphic materials by tuning their electrophoretic mobility differences. Our test case involved two different phases of calcium carbonate (aragonite and calcite, both CaCO3) in aqueous suspensions. Two serendipitous benefits arose when we used conventional additives in the suspension to prevent particle aggregation. First, phosphate-based additives increase the magnitude of the electrophoretic mobility differences between calcite and aragonite. This is advantageous because the greater the electrophoretic mobility difference, the less time and distance would be required for polymorph separation. Second, the phosphate additives prevent aragonite dissolution, even when the particles remain in aqueous suspension for many months. This is very fortuitous because it makes electrophoresis a non-destructive separation strategy for these calcium carbonate polymorphs.
        Speaker: Kristin Poduska (Memorial University of Newfoundland)
    • 10:30 AM 12:00 PM
      M1-3 Theory, Modelling, and Forecasting I (DASP) / Théorie, modélisation et prévisions I (DPAE) Colonel By B012

      Colonel By B012

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Prof. David Knudsen (University of Calgary)
      • 10:30 AM
        The “Impenetrable Barrier” Revisited: Bursting the VLF Bubble 15m
        In a recent paper, Baker et al. (Nature, 2014) reported the observation of an “impenetrable barrier” to the inner edge of the ultra-relativistic electron radiation belt. These authors demonstrated that this barrier location was not coincident with the location of the plasmapause nor any other identifiable magnetospheric boundary; nor could it be explained by the scattering of ultra-relativistic electrons into the loss cone by ground-based VLF transmitters. Here we show that the transport and energization timescales depend on gradients in the phase space density and not simply by timescales derived from the magnitude of the radial diffusion coefficient alone. Using these correctly formulated transport timescales, we show how the location of the “impenetrable barrier” can be explained in terms of radial diffusion, including the impacts of dynamical variations in phase space density gradients. Contrary to the suggestion by Baker et al., 2014 there does not appear to be any need for active local wave particle acceleration between the plasmapause and the edge of the barrier at L~2.8 since the radial diffusion rates appear to be sufficient to transport particles there during the most active times. The “impenetrable barrier” is explained as being the location where phase space density gradient and the diffusion coefficient combine to effectively block further inward ULF wave radial transport. During more active times the timescale for transport around L~2.8 can be increased allowing penetration of electrons into the slot. However, under typical conditions the activity does not remain high enough for a sufficiently long time to enable electron penetration below L~2.8. Overall, the “impenetrable barrier” is explained as a simple and natural consequence of the activity-dependent rates of ULF wave diffusive transport and significantly no local acceleration processes are required to explain how the particles reach the inner edge of the “barrier” at L~2.8.
        Speaker: Dr Stavros Dimitrakoudis (University of Alberta)
      • 10:45 AM
        Determination of global-scale diffusion coefficients in the stratosphere using a new model of local mixing 15m
        Due to the intermittency and spatial distribution of small layers of turbulence in the stratosphere, determination of large-scale diffusion coefficients is a non-trivial process. Previous models have assumed that all layers are perfectly mixed, but generally spatio-temporally disconnected. Our new model allows for partially mixed layers, especially for large and intense layers, which has profound effects on the global-scale diffusion coefficient. We also better represent the spatio-temporal distribution using a 2-dimensional model, as distinct from the more common one-dimensional model. Our newer model is used in combination with balloon and aircraft measurements of layer thicknesses and distributions to place limits on the possible values of large-scale diffusion in the stratosphere and upper troposphere. The values in the stratosphere are particularly well confined.
        Speaker: Wayne Hocking (University of Western Ontario)
      • 11:00 AM
        Development of the Canadian Ionosphere and Atmosphere Model 15m
        Current status of the Canadian Ionosphere and Atmosphere Model (C-IAM) project is described. The C-IAM has been composed from two pre-existing first principles models: the extended Canadian Middle Atmosphere (CMAM) and the ionospheric part of the Upper Atmosphere Model (UAM). The model domain extends from the surface to the inner magnetosphere and two-way coupling between the neutral atmosphere and ionosphere is implemented. These features make the C-IAM a self-consistent whole atmosphere model that is capable of studying both the impact of the lower atmosphere on the thermosphere and the ionosphere and the impact of geomagnetic conditions on the neutral atmosphere. In addition to the first principles modelling blocks, the C-IAM includes alternative empirical models (e.g., MSISE) which can optionally be used for specific studies. In order to reproduce the response to specific space weather events, the model has an option to accommodate the real (observed) high-latitudinal electric field and auroral energetic electron distribution. The C-IAM has been successfully applied to reproducing a number of observed thermospheric/ionospheric features. These include simulating the wave number 4 features observed in the nighttime O ionospheric emission at 135.6 nm, modeling the 732 nm O+ daytime emission and retrieving from it the atomic oxygen concentration, and explaining disturbances measured by the GOCE satellite accelerometers over high latitudes during geomagnetically active days. The presentation will introduce the model and describe these results.
        Speaker: Oleg Martynenko (York University)
      • 11:30 AM
        Farley-Buneman waves at large aspect angles 15m
        The Farley-Buneman (FB) instability mechanism provides an excellent explanation for the presence of large amplitude plasma waves in the cm to few m wavelength range in the high latitude E region whenever the ambient electric field exceeds 20 mV/m. Observations suggest that the instabilities are observed at their threshold speed when they reach their largest amplitudes. This can be explained in terms of a combination of decreasing electric field and increasing aspect angle inside individual structures. However, another feature of observations is that linear theory predicts instability for aspect angles smaller than 1.5 degree, up to maybe 2 degrees even though there is plenty of evidence to show that large amplitude structures exist at aspect angles well beyond 2 degrees during Farley-Buneman events. We show that this observational feature is caused by the weak altitude dependence of the eigenfrequency, which forces the aspect angle to grow monotonically with time. This means that after the structures have reached their maximum amplitude, they continue to exist, but with the caveat that their aspect angle increases while their amplitude decreases. This allows damped modes at large aspect angles to be observed. However, as the aspect angle increases, the phase velocity of the waves will also change, although that change is actually a strong function of the wavelength of the structures. This means that we must assess the real and imaginary part of the eigenfrequency to query the Doppler shift of the structures and see how they compare with observations at different radar frequencies. To this goal, we have studied both the simple fluid isothermal dispersion relation, as well as the full kinetic dispersion. Our results for sub-meter wavelengths show that the phase velocity remains very constant at only slightly less than the ion-acoustic speed as the aspect angle increases. At larger wavelengths, the transition to zero phase velocity proceeds according to Vd/(1+psi), a result in agreement with the simple fluid predictions based on small growth rate considerations. The transition wavelength is controlled by the ion collision frequency. We have used our calculations to determine how the phase velocity and the growth/decay rate depend on altitude (or collision frequency) and electric field conditions. The phase velocity calculations compare favorably with observations.
        Speaker: patrick perron (RMCC)
      • 11:45 AM
        Magnetosphere-Ionosphere Coupling at Substorm Expansion Phase Onset 15m
        With the explosive release of energy within a substorm, stored magnetic energy is quickly converted to plasma kinetic energy, resulting in dramatic changes in the large-scale magnetic topology of the Earth’s night-side magnetic field and in increases in the flux of energetic particles in near-Earth space, and generates an apparently repeatable time series of events in the dynamic aurora spanning many degrees of latitude and hours of local time. Whilst the processes leading to energy storage in the magnetotail are well-understood, the same cannot be said for the conditions which lead to rapid energy release rather than a more gradual dissipation of stored energy. Without an improved understanding of the conditions leading to the triggering of rapid destabilisation of the tail, the forecast of the timing and geographical region affected by large GICs remains largely impossible. Here we examine the potential role of magnetosphere-ionosphere coupling (MIC) in triggering large scale morphological changes in the magnetotail across many hours of local time. We present ground-based magnetometer and all-sky imager observations combined with conjugate in-situ observations of the magnetic fields and temperature anisotropies of electrons and ions from GOES as well as the NASA Van Allen Probes and THEMIS satellites. By utilising the extensive ground coverage available from the Geospace Observatory (GO) Canada array we resolve longitudinal and relative timing uncertainties between the measurement platforms at onset. We seek to establish a causal sequence of events and thereby examine especially the potential role of near-Earth MIC processes in the substorm sequence, particularly that of the Akasofu auroral evolution at onset – independent of whether this precedes or follows the onset of magnetic reconnection at the near-Earth neutral line.
        Speaker: Dr Stavros Dimitrakoudis (University of Alberta)
    • 10:30 AM 12:00 PM
      M1-4 Neutrinoless Double Beta Decay I (PPD-DNP-DTP) / Double désintégration beta sans neutrino I (PPD-DPN-DPT) Colonel By C03

      Colonel By C03

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Tony Noble (Queen's University)
      • 10:30 AM
        Neutrino-less double beta decay search with EXO-200 and nEXO 30m
        The Enriched Xenon Observatory (EXO) is an experimental program designed to search for the neutrinoless double beta decay of $^{136}$Xe. Observation of this decay would prove that neutrinos are massive Majorana particles (i.e. they are their own anti-particles), and constitute physics beyond the Standard Model. The first phase experiment, called EXO-200, has re-started operation at the WIPP mine in New Mexico, USA, using 200 kg of liquid xenon enriched to 80% in $^{136}$Xe in an ultra-low background time-projection chamber (TPC). The detector performance and response has been thoroughly tested and is well understood. With the EXO-200 detector sensitive searches for neutrinoless and two neutrino double beta decays have been performed along with searches for exotic decay modes and decays to excited states. Some of these searches provided the most stringent limits on these decay modes. In parallel to the operation of EXO-200, the development of nEXO, a next-generation liquid xenon TPC has started. The nEXO detector will consist of 5T enriched xenon and will be deployed at a selected underground laboratory, ideally the SNOLab facility in Sudbury. Advanced detection technologies are being developed to read out charge and scintillation signals from the xenon TPC, such as charge readout tiles and Si photo multipliers, respectively. With these technologies and the increased target mass, the nEXO detector has the potential to completely probe the inverted neutrino-mass scale. The status of the EXO-200 detector, detector performance, and analysis techniques applied to achieve the current results will be discussed. In addition, current design efforts for the future multi-ton experiment nEXO will be discussed.
        Speaker: Thomas Brunner (McGill University)
      • 11:00 AM
        Ba-ion extraction and identification from high pressure Xenon gas for nEXO 15m
        The Enriched Xenon Observatory (EXO) is searching for the lepton-number violating double beta decay ($0\nu\beta\beta$) in $^{136}$Xe. If experimentally confirmed, $0\nu\beta\beta$ will require the neutrino to be its own anti-particle, i.e. Majorana particle, and shed light on the neutrino-mass hierarchy. The currently running EXO-200 experiment uses 200 kg of Xenon enriched to more than 80% in $^{136}$Xe and obtained the limit of $T_{1/2}^{0\nu\beta\beta}≥1.1\times10^{25}$ years. In parallel, the development of nEXO has started which will deploy 5 tonnes of liquid xenon in a time-projection chamber and is expected to probe the inverted mass hierarchy of neutrino. One of the design goals of nEXO is to unambiguously differentiate true double beta decay events from background contributions through Ba-tagging, i.e. by identifying the daughter isotope $^{136}$Ba of the $^{136}$Xe decay. With an efficient Ba-tagging technique, the backgrounds can be virtually eliminated which dramatically increases the sensitivity of the $0\nu\beta\beta$ search. The nEXO collaboration is developing various Ba-tagging techniques for liquid and gas phase xenon. A setup is being developed for Ba-tagging in xenon gas. Its central component is an RF-funnel to extract Ba-ions from high pressure xenon gas (up to 10 bar) to a vacuum environment. The second stage, a linear Paul trap, cools the ions through buffer gas cooling and bunches them into a multi-reflection time-of-flight mass spectrometer to identify the Ba-ion by precision mass spectrometry. The RF-funnel has been built and tested to extract ions from xenon gas of up to 10 bar. The liner Paul trap is currently under development. The Ba-tagging setup will be presented and future works will be discussed.
        Speaker: Yang Lan (TRIUMF/UBC)
      • 11:15 AM
        SNO+ status 30m
        The SNO+ experiment is located at SNOLAB and is a multi-purpose scintillator neutrino detector. Currently the detector is being filled with water and prepared for commissioning. The first phase of the experiment will be the search for neutrinoless double beta decay with a 130Te loaded scintillator. Other physics goals include: lower energy solar neutrinos, reactor- and geo-antineutrinos as well as neutrinos from a potential nearby supernova. This presentation will give an overview over the experiment and give the current status.
        Speaker: Dr Christine Kraus (Laurentian University)
      • 11:45 AM
        Rn-222 Assays for SNO+ 15m
        SNO+ is a large, underground neutrino detector, redesigned from the SNO detector. Three separate phases of SNO+ will provide a diverse study of neutrinos, with one phase specifically dedicated to the search for neutrinoless double beta decay in Te-130. At a depth of 2 km underground, SNO+ is shielded from many cosmogenics, yet the decay of U-238 within the surrounding rock leads to high (∼3.54 pCi/L) levels of Rn-222 in the air. Two cryotrapping units capable of collecting Rn-222 into Lucas cells are under development: one for the water shielding tank surrounding the cavity, the other for the scintillator fluid inside the detector. Once radon has been collected the Lucas cells are then taken to surface and counted, which will verify if the targets of 3.5E−13 g U/g water and ∼1E−17 g U /g scintillator are met. The status of both units and the Lucas cell counting system are discussed. The scintillator collector is under construction, the water unit is undergoing recommissioning, and the Lucas cell counting system will be updated.
        Speaker: Janet Rumleskie (Laurentian University)
    • 10:30 AM 12:00 PM
      M1-5 Soft Matter and Polymers (DCMMP-DPMB) / Matière molle et polymères (DPMCM-DPMB) Colonel By D207

      Colonel By D207

      University of Ottawa

      Convener: Naomi Matsuura (University of Toronto)
      • 10:30 AM
        On the coalescence of two drops undergoing a head-on collision in a Bingham fluid 30m
        In this work, we consider the canonical problem of the drainage of a thin film of Bingham fluid squeezed out between two spherical, Newtonian drops pushed against each other under the action of an external force. The only prior research to have studied this problem is the analytical work due to Jeelani and coworkers (Can. J. Chem. Eng., vol. 65, pp. 384-390, 1987, and J. Phys. Chem., vol. 90, pp. 6054-6059, 1986.). Unfortunately, these results have been obtained from a simplistic lubrication analysis for nearly planar films, or for dimpled films with ad-hoc assumptions about the film shape. In this work, we have performed detailed numerical simulations of the evolution of the shape of a thin, Bingham film with an immobile interface based on the lubrication equations, and compare our trends with existing work on the drainage of Newtonian films. The drainage of a film of Bingham fluid between two colliding Newtonian drops differs from that of a Newtonian film in two principal ways. First, drainage rates are slower for Bingham films as compared to Newtonian films of the same viscosity. The difference becomes strong for low capillary numbers in the spherical configuration of the film, and for large capillary numbers in the dimpled configuration. Second, once the Bingham film becomes dimpled, it can freeze completely once it reaches a critical thickness. Counterintuitively, this critical thickness is independent of the force pushing the drops against each other! Our results suggest that on a map of drop radius vs. shear rate, the parameter regime for coalescence for Bingham films will be shrunk relative to Newtonian films, and will be completely hindered below a critical shear rate and above a critical drop size.
        Speaker: Dr Arun Ramachandran (University of Toronto)
      • 11:00 AM
        Assembly of Gold Nanoparticles in Blue Phase Liquid Crystals: Towards New Generation of Soft Nanocrystals 30m
        The use of nanoparticles in the field of nanotechnology is one of the most promising approaches for novel technological applications through the development of reconfigurable ordered structures with rich properties. As well, the coupling of nanoparticles within liquid crystals is an emerging topic in the field of soft matter that offers new possibilities for designing reconfigurable nanomaterials that respond to a wide range of external stimuli. In this work, we report the spontaneous formation of thermally reversible, cubic crystal nanoparticle assemblies in Blue Phases. Gold nanoparticles, functionalized to be highly miscible in cyanobiphenyl-based liquid crystals, were dispersed in Blue Phase mixtures and characterized by polarized optical microscopy and synchrotron small-angle X-ray scattering (SAXS). The nanoparticles assemble by selectively migrating to periodic strong trapping sites in the Blue Phase disclination lines. At the Blue Phase I to Blue Phase II phase transition, the nanoparticle lattice reversibly switches between two different cubic structures. The simultaneous presence of two different symmetries in a single material presents an interesting opportunity to develop novel dynamic optical materials. Recent progress in understanding the mechanism of nanoparticle self-organization is presented.
        Speaker: Mohamed Amine Gharbi (McGill University)
      • 11:30 AM
        Vibrating-Wire Rheology 15m
        We are investigating the use of a vibrating wire device to measure the viscoelastic moduli of non-Newtonian fluids. Our device consists of a 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. We measure the voltage induced across the wire as a function of frequency. An analytic expression can be derived relating the voltage across the wire to viscosity. For non-Newtonian fluids we modify the Newtonian expression to include a complex viscosity, allowing the viscoelastic moduli to be determined from the measured voltage. We discuss the design and operation of our vibrating wire rheometer and demonstrate its ability to accurately measure the properties of Newtonian and non-Newtonian fluids.
        Speaker: Cameron Hopkins (The University of Western Ontario)
      • 11:45 AM
        Deuterium NMR and Rheology of Microgel Colloids at Ambient and High Pressure 15m
        Microgel colloids exhibit a polymer collapse transition resulting in a large reduction in colloid size at high temperatures or pressures. They have potential for drug delivery and chemical separation applications that involve uptake and release of small or biological molecules. Our goal is to obtain a microscopic understanding of the structure and dynamics of the microgels by examining the temperature and pressure dependence of collapse transition in order to investigate the energetic and entropic contributions to polymer collapse. The nature of this collapse transition can be controlled by crosslink density (Cd) thus we plan a systematic study as a function of Cd. We have used deuterium NMR (2H-NMR) to probe the microscopic dynamics of cross-linked poly-N-isopropylacrylamide (p-nipam) chains, in microgel colloids, as a function of temperature and pressure. Dynamic light scattering (DLS) and rheology were employed to characterize the microgels and probe their macroscopic properties. The observed changes in particle size and viscosity by DLS and rheology measurements with temperature were related to changes in the internal structure of the microgel particle investigated by 2H-NMR. Microgels colloids were synthesized with deuteron labels on the nipam side chains (d7-nipam) or on the backbone (d3-nipam). 2H-NMR spectra of both suspensions indicated freely moving chains in the microgel particle at low temperature, and a nearly immobilized fraction of the d3-nipam suspension above 35°C, consistent with DLS observations of transition from swollen to collapsed colloids. We continue to investigate the role of crosslink density in microstructure and macroscopic response by 2H-NMR, rheology and DLS.
        Speaker: Ms Suhad Sbeih (Memorial University of Newfoundland)
    • 10:30 AM 12:00 PM
      M1-6 Laser-Plasma Interactions (DPP-DAMOPC) / Interactions laser-plasmas (DPP-DPAMPC) SITE C0136

      SITE C0136

      University of Ottawa

      Convener: Lora Ramunno (University of Ottawa)
      • 10:30 AM
        MicPIC perspectives on light-matter interactions in strongly-coupled systems 30m
        A key challenge in modelling laser-driven strongly-coupled plasmas is to properly resolve both microscopic and macroscopic phenomena. Atomic collision processes require angstrom spatial resolution, whereas the macroscopic length scale is determined by the wavelength of the incident light. For example, modelling the complete dynamics of a near-infrared laser pulse driving a solid-density plasma requires to resolve about four orders of magnitude in space (from angstrom to micron) and to trace about $10^{10}$ classical particles, in combination with radiation and laser propagation. In this talk, I present an overview of the microscopic particle-in-cell (MicPIC) approach whose parallel implementation, designed for large-scale distributed computations, can fulfill all of these demands. Parallel MicPIC is an important step toward a better understanding of the links between the atomic-scale origin of optical phenomena and their observable manifestations. Our ultimate goal is to bring a complete description of light-matter interactions in strongly-coupled systems that includes all the relevant physics, from atomic dynamics to wavelength-scale phenomena, like scattering and diffraction.
        Speaker: Charles Varin (University of Ottawa)
      • 11:00 AM
        Dynamics of ultrafast laser processing of materials 30m
        Transient free electron plasma is created during the leading edge of an intense ultrafast laser pulse irradiation of a material. Subsequent interaction of this plasma with the rest of the incident light is often ignored in laser processing of materials. We will show that light-plasma interaction plays an important role resulting in polarization dependent features both on the surface and inside the bulk. Local field enhancement leads to asymmetric electron density distribution that is either parallel or perpendicular to the laser polarization depending on the transient plasma density. We demonstrate polarization effects in ablation of silicon and polymethylmethacrylate, and in refractive index modification of silica glass.
        Speaker: Ravi Bhardwaj (University of Ottawa)
    • 10:30 AM 12:00 PM
      M1-7 Atomic and Molecular Spectroscopy and Precision Measurements I (DAMOPC) / Spectroscopie atomique et moléculaire et mesures de précision I (DPAMPC) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Alan Madej
      • 10:30 AM
        **WITHDRAWN** Optical atomic clocks for gravitational wave physics 30m
        Gravitational wave (GW) astronomy has entered a new era with the direct detection of dekahertz-band GW signals by laser interferometers. As with the electromagnetic spectrum, observing gravitational waves in a range of different frequency bands will yield complementary insights into the astrophysics of gravitating objects. Gravitational waves at micro-hertz to milli-hertz frequencies can be detected using an array of optical atomic clocks on satellites, by leveraging the extreme precision available with these clocks. This method affords a technologically feasible approach to imaging the universe in a novel GW band. To enable this method, we are developing optical atomic clocks for use on board satellites, using a simplified scheme based on two-photon transitions. In this talk, I will describe the method of GW detection using optical atomic clocks, and present our progress towards building a portable clock.
        Speaker: Dr Amar Vutha (University of Toronto)
      • 11:00 AM
        Experimental and Theoretical He-Broadened Line Parameters of Carbon Monoxide in the Fundamental Band 15m
        We will discuss recent spectroscopic results for He-broadened transitions of carbon monoxide in the fundamental band, performed over a range of temperatures from 80 to 296 K. Experimentally, the spectral line parameters and their temperature dependencies were retrieved using a multispectrum analysis software and different line shape models (Voigt, speed dependent Voigt, Rautian, Rautian with speed dependence). In addition, we have performed theoretical calculations for He-broadened Lorentz half-width coefficients and He- pressure-shift coefficients for the same transitions. The line mixing coefficients were calculated using the exponential power gap and energy corrected sudden scaling laws. Our results were compared with published results.
        Speaker: Adriana Predoi-Cross (Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB, T1K 6R4 Canada)
      • 11:15 AM
        Self- and Hydrogen-Broadened Line Parameters of Carbon Monoxide in the First Overtone Band 15m
        We have re-analyzed room-temperature spectra of first overtone band of CO and CO broadened by hydrogen. We have employed the Voigt, speed depended Voigt, Rautian, and Rautian with speed dependence line shape models and a multispectrum fit software [1]. The line mixing coefficients have been calculated using scaling laws. The CO line widths in CO-Hydrogen and CO-CO collisions were calculated using the classical impact theory [2] to determine the dipole absorption half-widths and exact 3D Hamilton equations to simulate molecular motion. We used Monte Carlo averaging over collision parameters and simple interaction potential (Tipping-Herman + electrostatic) [3-4] and assumed the molecules to be rigid rotors. The dependencies of CO half-widths on rotational quantum number J<24 are computed and compared with measured data at room temperature. REFERENCES 1. D.C. Benner, C.P. Rinsland, V. Malathy Devi, M.A.H. Smith, D. Atkins, J. Quant. Spectrosc. Rad. Transfer 53(6) 705-721 (1995). 2. R.G. Gordon, J. Chem. Phys. 44, 3083-3089 (1966); ibid., 45, 1649-1655 (1966). 3. J.-P. Bouanich, A. Predoi-Cross, J. Molec Structure 742, 183-190 (2005). 4. A. Predoi-Cross, J.P. Bouanich, D. Chris Benner, A.D. May, J.R. Drummond, J. Chem. Phys. 113, 158-168 (2000).
        Speaker: Prof. Adriana Predoi-Cross (Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB, T1K 6R4 Canada)
      • 11:30 AM
        Tune-out Wavelengths and Polarizability for the Helium $\mathbf{1s2s}\;\mathbf{^{3}}$S State.$^*$ 15m
        This paper is part of a joint theoretical/experimental project to test QED by measuring the tune-out wavelength of helium near the 413 nm line where the frequency-dependent polarizability vanishes [1]. As a first strep, we calculate a high-precision value for the static polarizability defined in the nonrelativistic limit as the second-order perturbation energy due to the perturbation $V=eFr\cos{\theta}$ where $F$ is the electric field strength. For a two electron atom such as helium, high precision results are obtained by use of an explicitly correlated Hylleraas basis set to represent the complete set of intermediate states. We also include for the first time relativistic corrections due to the Breit interaction terms proportional to $p_1^4+p_2^4$, $\delta(r_{12})$, $\delta(r_1)$ and the orbit-orbit interaction [2]. For the $2$ $^3S$ state of helium, we find a relativistic contribution to the polarizability with finite nuclear mass corrections included of $-0.098\,765770(9)$ $a_0^3$ atomic units, where $\alpha$ is the fine structure constant.\\[0pt] [1] B.M. Henson et al. Phys.\ Rev.\ Lett.\ {\bf 115}, 043004 (2015).\newline [2] K. Pachucki and J. Sapirstein, Phys. Rev. A \textbf{63}, 012504, (2000).\newline $^*$Research supported by NSERC.
        Speaker: Mr Jacob Manalo (University of Windsor)
      • 11:45 AM
        FTIR Synchrotron Spectroscopy of the Asymmetric C-H Stretching Bands of Methyl Mercaptan (CH$_{3}$SH) – A Perplexity of Perturbations 15m
        The infrared Fourier transform spectrum of the asymmetric C-H stretching bands of CH$_{3}$SH has been recorded in the 2950-3100 cm$^{-1}$ region using synchrotron radiation at the FIR beamline of the Canadian Light Source in Saskatoon. Assignment of numerous torsion-rotation sub-bands for the asymmetric stretches has revealed a surprising pseudo-symmetric behavior, in which each band is seen in only one of the two possible $\Delta$$K$ selection rules. The upper states of the two asymmetric stretching vibrational bands thus appear to behave more like $l$ = $\pm$1 components of a degenerate $E$ state of a symmetric top rather than distinct vibrational states. The two components are separated by about 1.5 cm$^{-1}$ at $K$ = 0, and then diverge linearly at higher $K$ with torsional oscillation amplitude similar to that of the ground state of about 1.3 cm$^{-1}$. The divergence is consistent with an $a$-type Coriolis splitting picture with an effective Coriolis constant $\zeta$ $\approx$ 0.075.
        Speaker: Dr Li-Hong Xu (Physics Dept., University of NB)
    • 12:00 PM 1:00 PM
      Lunch / Diner
    • 12:00 PM 1:00 PM
      New Faculty Lunch Meeting with NSERC / Dîner-rencontre des nouveaux professeurs avec le CRSNG SITE C0136

      SITE C0136

      University of Ottawa

      Convener: Donna Strickland (University of Waterloo)
    • 12:00 PM 1:00 PM
      Science Policy Workshop / Atelier Politique scientifique Colonel By C03

      Colonel By C03

      University of Ottawa

      Convener: Kristin Poduska (Memorial University of Newfoundland)
    • 1:00 PM 2:30 PM
      M2-1 Nuclear Structure I (DNP) / Structure nucléaire I (DPN) Colonel By B012

      Colonel By B012

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Dennis Muecher (University of Guelph)
      • 1:00 PM
        Half-life measurements of nuclei around the doubly-magic 100Sn 15m
        $^{100}$Sn is the heaviest self-conjugate doubly magic nuclei with $N = Z = 50$. Research on this nucleus has been aggressively pursued, for its properties yield valuable information on many topics of nuclear physics: the robustness of the magic number 50 far from stability, the effect of proton-neutron interaction, and the location of the proton dripline and the end of the rapid proton-capture process path, to name a few. Due to the lack of experimental information on the structure of $^{100}$Sn itself, the properties of $^{100}$Sn have to be inferred from spectroscopy results of the neighbouring isotopes. As one of the experimental observables, half-life measurements of these radioactive nuclei reflect their general stability, while enabling the calculation of transition strengths for decay matrix elements. These results serve as benchmark tests against modern shell model calculations and inputs for astrophysical rapid proton-capture models of nucleosynthesis. Record quantities of $N \sim Z \leq 50$ nuclei 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 high-purity germanium detectors for $\gamma$ rays, and WAS3ABi, a set of position-sensitive silicon detectors for positrons and protons. Half-lives of exotic $^{91}$Pd, $^{95}$Cd, $^{97}$In, and $^{99}$Sn isotopes were measured for the first time, and higher precision in half-lives of several isotopes in the vicinity of $^{100}$Sn was achieved. A systematic study of the measured half-lives will be presented, probing the robustness of the magic number 50 in nuclei near the proton dripline.
        Speaker: Mr Joochun (Jason) Park (University of British Columbia/TRIUMF)
      • 1:15 PM
        Single Particle Structure and Shapes of Exotic Sr Isotopes 15m
        Nuclei near the so called magic numbers of protons and neutrons are observed to have a spherical shape in their low lying states. Nuclei between magic numbers, where the binding energy tends to be less, are often observed to show deformation in low lying states. These deformations 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. Through $^{95}$Sr(d,p) a strong occupation of the first excited 0$^{+}$ state and a weak population of the second 0$^{+}$ state was measured. This suggests that there is strong mixing between the ground state and the first 0$^+$. These results discussed in the context of the evolution of single-particle structure will be presented.
        Speaker: Steffen Cruz
      • 1:30 PM
        A Study on Low Spin States in 154Gd Using (p,p') Reaction 15m
        Located at the stability line, the low lying spin states of the 154Gd nucleus were investigated at the University of Jyväskylä accelerator laboratory in Finland using the 154Gd(p,p'γ) reaction. A proton beam of 12 MeV was used to excite the 154Gd target, with the gamma-rays from the reaction detected with the JUROGAM II array, while the LISA charged-particle spectrometer was used for detection of the inelastically scattered protons. This experiment marked one of the first uses of the LISA spectrometer at Jyväskylä, and enabled the efficient tagging of the proton-emitting reactions, thus helping to distinguish between the (p,p'), and the much more copious (p, xn) channels. By analyzing the peaks obtained from the gamma-gamma, and gamma-gamma-proton, coincidence matrices, a decay scheme has been built using the RadWare software Escl8r. Experimental methods, new transitions, and future steps will be discussed.
        Speaker: Mr Harris Bidaman (University of Guelph)
      • 1:45 PM
        Investigating the nature of excited 0$^+$ states populated via the $^{162}$Er(p,t) reaction 15m
        Many approaches have been implemented in nuclear structure physics to interpret the nature of excited states in well-deformed nuclei, such as vibrational excitations in $\beta$ phonons and $\gamma$ phonons, as well as pairing excitations. However, due to a paucity of data about excited states in rare earth nuclei, in many cases even the first excited state, 0$^+_2$, is not known. Direct two-neutron transfer reactions are a valuable tool for probing $0^{+}$ $\rightarrow$ $0^{+}$ transitions in well-deformed nuclei. Excited $0^+$ states in the $N=92$ nucleus $^{160}$Er have been studied via the ($p,t$) reaction with a highly-enriched $^{162}$Er target at the Maier-Leibnitz Laboratory in Garching, Germany, using a proton beam energy of 22 MeV and 24 MeV supplied by a Tandem Van de Graaff. Reaction products were momentum-analyzed with a Quadrupole-3-Dipole magnetic spectrograph. Strong population of the 0$^+_2$ state was observed with a large cross section greater than any other excited $0^+$ state. Preliminary results of the relative population of excited 0$^+$ states in $^{160}$Er and a possible intepretation will be presented.
        Speaker: Christina Burbadge (University of Guelph)
      • 2:00 PM
        Simulating the DESCANT Neutron Detection Array with the Geant4 Monte Carlo Toolkit 15m
        The DEuterated SCintillator Array for Neutron Tagging (DESCANT) is a newly developed high-efficiency neutron detection array composed of 70 hexagonal deuterated scintillators. Due to the anisotropic nature of elastic neutron-deuteron (n,d) scattering, the pulse-height spectra of a deuterated scintillator contains a forward-peaked structure that can be used to determine the energy of the incident neutron without using traditional time-of-flight methods. Simulations of the array are crucial in order to interpret the DESCANT pulse heights, determine the efficiencies of the array, and examine its capabilities in conducting various nuclear decay experiments. To achieve this, we plan: (i) a verification of the low-energy hadronic neutron physics packages in Geant4, (ii) a comparison of simulated spectra with data from a simple cylindrical “test can” detector geometry, (iii) expanding the simulated light response to a prototype DESCANT detector, and (iv) simulating the entire DESCANT array.
        Speaker: Mr Joseph Turko (University of Guelph)
    • 1:00 PM 2:30 PM
      M2-2 Molecular Biophysics (DPMB) / Biophysique moléculaire (DPMB) Colonel By B205

      Colonel By B205

      University of Ottawa

      Convener: Francis Lin (University of Manitoba)
      • 1:00 PM
        Femtomedicine in Cancer: Discovery of New Antitumor Molecules for Natural Targeted Chemotherapy and Radiotherapy of Cancers 30m
        The conquest of cancer continues to pose great challenges to medical science. There is a compelling need for innovative cancer research integrating biomedical sciences with physical sciences in order to ultimately conquer cancer. Femtomedicine (FMD), which integrates femtosecond time-resolved laser spectroscopy with biomedical sciences, was recently coined to advance fundamental understanding and therapies of human diseases notably cancer [1,2]. Our studies in FMD have led to the discoveries of the reductive damaging mechanism in DNA and living cells and the molecular mechanisms of action of existing anti-cancer agents. These have offered unique opportunities to develop new effective drugs for high-performance therapy of cancer[3,4]. We have particularly found a new class of non-platinum-based anticancer compounds (called FMD compounds) for natural targeted chemotherapy and radiotherapy of a variety of cancers, e.g., cervical cancer, ovarian cancer, head and neck cancer, breast cancer, lung cancer, etc. Treatments of various cancer cells in vitro and in vivo mouse xenograft models with FMD compounds led to effective chemotherapy and enhanced radiotherapy, while the compounds themselves induced no or little systemic and radiation toxicity. These compounds are therefore a new class of potent antitumor agents that can be translated into clinical trials for targeted chemotherapy and radiotherapy of multiple types of cancer. The results also show that FMD can bring breakthroughs in understanding fundamental biological processes and lead to advances in cancer therapy. This presentation will discuss some progress in this new frontier—FMD in Cancer. 1. QB Lu, Mutat. Res.: Rev. Mutat. Res. 704, 190-199 (2010). 2. J Nguyen et al., PNAS 108, 11778-11783 (2011). 3. QB Lu et al., EBioMedicine 2, 544-553 (2015). 4. CR Wang et al., Mol. Cancer Ther. (2016). doi: 10.1158/1535-7163.MCT-15-0862.
        Speaker: Prof. Qing-Bin Lu (University of Waterloo)
      • 1:30 PM
        Observation of coupling between microscopic diffusion and macroscopic elasticity in soft matter 15m
        Material diffusion processes are fundamentally driven by local microscopic interactions. Many important applications of diffusion, including drug delivery, are based on this concept. However, some orientational microscopic interactions can generate a collective macroscopic organization. Thus, macroscopic boundary conditions may affect the microscopic diffusion if orientational interactions are involved in the diffusion process. Liquid crystalline materials are the best examples of orientationally correlated (oriented) molecular complexes where we can observe such phenomena. However, many other self-organized (oriented) material systems, particularly those present in the biological tissue, have similar behavior. My presentation will describe the experimental observation and theoretical modeling of the diffusion of chiral guest molecules in a nematic liquid crystal host and will discuss the possible implications of our observation in the drug diffusion phenomena in the biological tissue. Future developments will be also shortly discussed.
        Speaker: tigran galstian (Laval University)
      • 1:45 PM
        The Lipid Bilayer Provides a Site for Cortisone Crystallization at High Cortisone Concentrations 15m
        Cortisone is an injected anti-inflammatory drug that is used to treat inflammation. Cortisone’s mechanism of action involves binding to an intracellular receptor which transduces a biochemical cascade to reduce the production of inflammatory prostaglandins. However, cortisone is known to confer side effects, such as pain, known as a “steroid flare” for which the mechanism is unknown. Using X-ray diffraction of highly oriented, multi lamellar stacks of lipid membranes and molecular dynamics (MD) simulations, we locate the cortisone molecules within the bilayer, quantified its crystallization, and measured the respective insertion dynamics [1]. At low cortisone concentrations, the molecules localize near the glycerol group of the lipid, and decreased membrane width in a dose-dependent manner. The formation of the cortisone crystallites was observed at higher concentrations, which conferred to a cubic lattice. While the cortisone molecules align parallel to the bilayers at low concentrations, they start to penetrate the hydrophobic core at higher concentrations. Trans-membrane crystallites start to nucleate when the membrane thickness has decreased such that cortisone molecules in the different leaflets can find partners from the opposite leaflet. The results manifests to potentiate a mechanism of action for “steroid flares” by forming crystallites in the bilayer, and offers greater understanding of the drug’s action. [1] RJ Alsop, **A Khondker**, JS Hub, MC Rheinstädter,. Sci. Rep. 6, 22425 (2016).
        Speaker: Adree Khondker (McMaster University)
      • 2:00 PM
        Coarse-grained simulations of highly driven DNA translocation from a confining nanotube 15m
        Driven DNA translocation through a nanoscopic pore has been the focus of many studies in recent years both due to its importance in biological processes and as a promising new technology to probe single DNA molecules. However, the simple process of driving monodisperse DNA chains through a pore often leads to surprisingly wide distributions of translocation times. In the regime where the driving force is high, such that translocation occurs much faster than the time required for the chain to relax, the different conformations that a DNA chain can have at the initiation of the translocation is a major contributor to this broadening. As an effort to reduce the broad distribution of translocation times, we test a situation where the DNA is placed inside a small nanotube whose purpose is to limit the range of initial conformations. We present the results of coarse-grained Langevin Dynamics simulations where the DNA is confined inside both infinitely long tubes and finite-length end-capped tubes. We demonstrate that the results for both tube geometries can be reproduced by a theoretical Tension-Propagation model. Since the end-capped tube contains an extra degree of freedom compared to the semi-infinite tube, we show how both cases need different strategies in order to minimize the coefficient of variation, and obtain tighter distributions of the translocation time.
        Speaker: David Sean (University of Ottawa)
      • 2:15 PM
        Organization of Nucleotides in Different Environments: Implications for the Formation of First RNA under Prebiotic Conditions 15m
        How nucleic acids first assembled and then incorporated into the earliest forms of cellular life 4 billion years ago remains a fundamental question of biology. It is postulated that prior to today's DNA, RNA, and protein-dominated world, RNA was used for genetic storage and as a catalyst for reactions, such as polymerization. RNA is a polymer chain of nucleotides linked to a ribose-phosphate backbone. Polymerization of nucleotides occurs in a condensation reaction in which phosphodiester bonds are formed. However, in the absence of enzymes and metabolism there has been no obvious way for RNA-like molecules to be produced and then encapsulated in cellular compartments, an essential first step in the origin of cellular life. To support the hypothesis that environmental conditions in the neighbourhood of volcanic hydrothermal springs could act to organize monomeric nucleotides through various noncovalent interactions and chemical reactions in the prebiotic era, we investigated 5'-adenosine monophosphate (AMP) and 5'-uridine monophosphate (UMP) molecules captured in different matrices that have been proposed to promote polymerization, namely multi-lamellar phospholipid bilayers, nanoscopic films, ammonium chloride salt crystals and Montmorillonite clay [1]. Two nucleotides signals were observed in our X-ray diffraction experiments, one corresponding to a nearest neighbour distance of around 4.6 Å and a second, smaller distance of 3.45 Å. While the 3.45 Å distance agrees well with the distance between stacked base pairs in the RNA backbone, the 4.6 Å distance can be attributed to un-polymerized nucleotides that form a disordered, liquid-like structure. From the relative strength of the two contributions, the effectiveness of the different environment for producing RNA-like polymers was determined. [1] S Himbert, M Chapman, DW Deamer, Maikel C. Rheinstädter, submitted to PLOS ONE.
        Speaker: Sebastian Himbert (Mcmaster University)
    • 1:00 PM 2:30 PM
      M2-3 Ultrafast and Time-Resolved Processes (DAMOPC) / Procédés ultrarapides et résolus dans le temps (DPAMPC) Colonel By D207

      Colonel By D207

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Lindsay LeBlanc (University of Alberta)
      • 1:00 PM
        Nonlinear Optical Response of Arrays of Metamolecules: New Observations and Ways of Enhancement 30m
        Recent advances in nanofabrication made it possible to produce arrays of artificial structures (metamolecules) with good optical quality. This, in turn, enabled the observation of many unusual phenomena, such as invisibility cloaking, negative refraction, generation of beams with orbital angular momentum and other modifications to the polarization state of the incoming light. Of special importance is the nonlinear optical response of such arrays. Since there is a lot of flexibility in the choice of the materials and shapes of individual metamolecules, it is expected that the nonlinear optical properties of such arrays could be largely controlled and tailored. In this talk, we will be discussing two methods of such tailoring. One of the methods involves the resonant enhancement of the overall nonlinear optical response enabled by the coupling between the metamolecules in the arrays. Another method of tailoring the nonlinear optical properties of an array of metamolecules relies on local-field effects. It has been recently shown that such effects are capable of inducing an additional contribution to a higher-than-the-lowest-order nonlinear optical response present in a material medium. This contribution is of cascaded nature: it relies on the multistep contribution of a lower-order nonlinearity to a higher-order susceptibility. When induced by local-field effects, such a cascading is of local nature: it occurs at the scale of the neighboring metamolecules forming the array. This unique feature distinguishes this effect from a better known macroscopic cascading. Microscopic cascading is a relatively new effect that has not been studied in detail yet. We present our resent efforts at identifying the conditions under which this effect could become the dominant contribution to a higher-order nonlinear optical susceptibility.
        Speaker: Prof. Ksenia Dolgaleva (University of Ottawa)
      • 1:30 PM
        Effects of Refractive Index Mismatch on Stimulated Raman Scattering And Coherent Anti-Stokes Raman Scattering Microscopy 15m
        Nonlinear optical microscopy techniques, such as stimulated Raman scattering (SRS) and coherent anti-Stokes Raman scattering (CARS), allow for label-free chemically-sensitive non-destructive video-rate imaging of biological processes[1]. SRS is of particular interest due to its improved image contrast, high spectral sensitivity and low acquisition times. Correctly interpreting images produced by nonlinear optical processes is of vital importance. Earlier we showed AM-SRS signals depend upon the structure of $\chi^{(3)}$ in the background medium, and thus is not background free[2]. We now show that even for the modest linear refractive index mismatches typically found in biological tissues, near-field enhancements can cause significant signal distortions in both CARS[3] and SRS. We employ finite-difference time-domain simulations to determine the near- and far-fields of wavelength-sized spherical Raman-active objects in a nonresonant Kerr medium illuminated by a tightly-focused laser source. We find that, depending upon the shape of the Raman scatterer, enhanced near-fields can create a signal an order of magnitude larger than what would be expected, and with a peak in the image that does not directly correspond to the object location. Additionally, the radiation pattern is heavily influenced and as a consequence we find that the numerical aperture of the collecting lens becomes important. Filtering techniques will not eliminate any of these effects as these distortions are caused by a microlensing effect within the scatterers. Understanding these distortions is key to correctly interpreting both CARS and SRS images. Even without any Raman-active material present, the underlying $\chi^{(1)}$ structure can introduce background signals in AM-SRS and CARS. This highlights the need for frequency-based filtering methods such as FM-SRS and FM-CARS or hyperspectral analysis. **References** 1. B. Saar et al., **Science** 330, 1368–1370 (2010). 2. K. Popov et al., **Opt. Lett.** 37, 473–475 (2012). 3. J. Lin et al., **Opt. Express** 17, 2423–2434 (2009).
        Speaker: Jarno Nicolaas van der Kolk (University of Ottawa)
      • 1:45 PM
        Super-Critical Phase-Matching for Generation of Structured Light Beams 15m
        Radially and azimuthally polarized light beams have garnered increased interest for their properties and uses in fundamental and applied optics. Radial polarizations are parallel to the central axis of the beam (at all points pointing toward the beam center); azimuthal polarizations are orthogonal to this, running perpendicular to the central axis of the beam. Photon pairs with these polarizations have applications in quantum information, such as alignment-free quantum key distribution and superdense coding. We present a method to directly produce, through spontaneous parametric down-conversion (SPDC), photon pairs with radial and azimuthal polarizations. In SPDC, a pump photon is absorbed and two lower-frequency photons, the signal and idler, are produced such that energy and momentum are conserved (i.e. phasematching). These photons may be produced in the same direction as the pump beam, in collinear phase-matching, and may have polarizations that are parallel (type I) or orthogonal (type II). In our new geometry, the pump beam is a Bessel-Gauss beam, which we have modeled as a distribution of Gaussian beams forming the surface of a cone. This cone is centered on the crystal axis, which is parallel to the central pump propagation direction. The opening angle of this cone is set so that each Gaussian pump beam in the pump distribution meets the phase-matching conditions. We have simulated the output distributions for the signal and idler photons in type I and type II phase-matching. For type II phase-matching, the signal and idler photons are emitted along three concentric cones, which we have named ‘super-cones’. These photons will have orthogonal polarizations: one will be radially polarized and the other azimuthally polarized. In type I phase-matching, the signal and idler photons will both be azimuthally polarized, and will be emitted along a single super-cone that is collinear with the pump beam. We have demonstrated a novel method to directly produce radially and azimuthally polarized photon pairs. These unique polarization states have applications in quantum information and quantum metrology, and are opening new research directions in these fields. Boeuf, N., et. al. Opt. Eng. 39(4): 1016-1024, 2000. Quabis, S., et. al. Opt. Comm. 179(1):1-7, 2000.
        Speaker: Rebecca Saaltink (University of Ottawa)
      • 2:00 PM
        A Method to Arbitrarily Transform the Polarization of Light Variably Across a Beam 15m
        Light fields with spatially varying polarization have a wide range of potential uses in the areas of telecommunication, imaging, lithography, and quantum information. A spatial light modulator (SLM) is a two dimensional array of liquid crystal cells that can control phase, polarization, and intensity of light point by point across a beam’s spatial profile. We have developed methods to implement general polarization transformations using SLMs. That is, we can apply arbitrary polarization rotations that vary controllably across a beam. In quantum information, our methods in principle could enable the parallel processing of millions of optical modes, one for each cell. As an experimental example of the power of these methods, we take a beam with a non-uniform polarization across its spatial profile and convert it to be uniform. Such a correction could be useful for astronomy or microscopy imaging systems that suffer from polarization aberrations. In order to demonstrate the procedure’s effectiveness we present point by point measurements of the polarization before and after the correction.
        Speaker: Mr Matthew Runyon (Department of Physics and Max Planck Centre for Extreme and Quantum Photonics, University of Ottawa, Canada)
      • 2:15 PM
        Single-shot holographic measurement of attosecond pulses and the time-dependent field of an ultrashort pulses 15m
        We demonstrated simultaneous all-optical, single-shot holographic measurement of attosecond high harmonic pulses and a femtosecond laser pulse. To achieve this, we introduce a weak laser beam into the harmonic generation medium together with the strong driving laser field. The weak laser field perturbs the trajectories of ionized electrons that are responsible for high harmonic generation and therefore diffracts the harmonic radiations. Since the periodic structure in the near-field harmonic radiations implies cross-correlation between the attosecond pulse and the perturbing laser pulse, we can achieve temporal characterization by measuring the diffracted high harmonic radiations. However, since the far-field intensity distribution is insensitive to the near-field harmonic radiations, we superposed a reference X-ray beam generated from a secondary harmonic source. The measured harmonic spectrograph shows dense fringes that originate from two-source interference. The rapid oscillation enables us to reconstruct the near-field harmonic radiations by applying Fourier transform. As a result, we determined the attosecond pulses, showing a pulse duration of 390 as, and the time-dependent electric field of the perturbing pulse from the retrieved near-field image. The duration of the perturbing pulse that we obtain is consistent with the result achieved by a conventional FROG measurement. The single-shot measurement method is a fast, robust and effective way to monitor high harmonic or attosecond pulses. Consequently, it will be a new technique to probe ultrafast strong-field interactions in many materials.
        Speaker: Dr Dong Hyuk Ko (Joint Attosecond Science Laboratory, University of Ottawa and National Research Council of Canada)
    • 1:00 PM 2:30 PM
      M2-4 Mathematical Physics (DTP) / Physique mathématique (DPT) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Jean-Francois Fortin (Laval University)
      • 1:00 PM
        A Farewell to Symmetries: Quasilocal Frames in General Relativity 30m
        In this talk, I will give a brief introduction to rigid quasilocal frames (RQF) which have been proposed as a geometrically natural way to define spatially extended reference frames in general relativity. In particular, I will explore their usefulness as a tool for constructing completely general conservation laws that do not rely on the presence of spacetime symmetries and include both matter and gravitational contributions without the need for any ad hoc structures such as pseudotensors. In doing so, I show how the RQF approach affords a deeper understanding of the nature of gravitational fluxes via the equivalence principle and discuss more concrete potential applications.
        Speaker: Dr Paul McGrath
      • 1:30 PM
        The Moyal Equation for open quantum systems 30m
        We generalize the Moyal equation, which describes the dynamics of quantum observables in phase space, to quantum systems coupled to a reservoir. It is shown that phase space observables become functionals of fluctuating noise forces introduced by the coupling to the reservoir. For Markovian reservoirs, the Moyal equation turns into a functional differential equation in which the reservoir's effect can be described by a single parameter.
        Speaker: Karl-Peter Marzlin (St. Francis Xavier University)
      • 2:00 PM
        Citation Networks in Law: Detection of Hierarchy and Identification of Key Events 15m
        Citation networks can be used to make powerful analyses about human intellectual activity in diverse fields. However, universal rules governing their structure and dynamics have not yet been discovered. To address this, my research probes the influence of social and institutional hierarchy on the structure and dynamics of citation networks. Hierarchy is a fundamental feature of all human social organizations; therefore, any citation network is necessarily embedded in an “underlying” hierarchy that in turn determines properties of the network. Through this new way of analyzing citation networks, my research seeks to advance the understanding of phenomena central to societal progress, such as: the emergence of research fronts and seminal publications; how paradigms form, take hold, become unstable, and collapse; innovation and the emergence of new technologies; and the emergence of new legal doctrine and the evolution of the law. I will present an analysis of a novel data set (that I have created) that covers all hierarchical levels of the Canadian legal system for a specific area of law (defamation law). My presentation will show: 1) an evaluation of a recently published method for inferring hierarchies among scientific journals based on scientific citation networks by applying that method to my novel data set, in order to determine if the method is capable of detecting the known underlying court hierarchy; and 2) ways in which network analysis methods (node-ranking via authority scores and node-grouping via community detection/clustering) can identify important periods in the evolution of the law (e.g. turning-points in legal “eras”, in which the law is applied in a new way). Points 1 and 2 will be discussed in relation to the overarching goal of understanding the influence of underlying hierarchy on the structure and evolution of citation networks in law and other fields.
        Speaker: Mr Joseph Hickey (University of Calgary)
    • 1:00 PM 2:30 PM
      M2-5 Energy Frontier: SUSY and Exotics (PPD) / Frontière d'énergie: supersymétrie et particules exotiques (PPD) MacDonald 146

      MacDonald 146

      University of Ottawa

      Convener: Brigitte Vachon (McGill University (CA))
      • 1:00 PM
        Operation and Performance of the ATLAS detector in LHC Run II 30m
        The ATLAS detector at CERN in Geneva, Switzerland, detects the particles produced in proton-proton collisions created by the Large Hadron Collider. Following the very successful Run I data taking period during 2009-2012 where the proton-proton collision energy was at maximum 8 TeV, we have now started the Run II data taking period with the significantly higher collision energy of 13 TeV. This talk will present the status of the operations and performance of the ATLAS detector, including details on data acquisition, trigger, reconstruction and calibration performance. Particular focus will be given to the Canadian contributions.
        Speaker: Dag Gillberg (Carleton University)
      • 1:30 PM
        Helium-3 thermal neutrons counters in the SuperKEKB commissioning detector 15m
        Thermal neutron detectors have been installed into BEAST II, the commissioning detector of the SuperKEKb accelerator. These detectors use helium-3 to detect neutrons via the capture process $^{3}$He$ + n \rightarrow ^{3}$H$+p+720keV$ and are only sensitive to thermal neutrons, and are therefore an excellent means of monitoring the thermal neutron flux in the BEAST. Commissioning began in February and continued until the end of May, providing a large variety of beam conditions in which to measure the neutron flux. These flux measurements are compared with simulation in order to test the validity of the simulations.
        Speaker: Samuel de Jong (University of Victoria)
      • 1:45 PM
        Measurement of the electromagnetic background radiation during SuperKEKB commissioning 15m
        The SuperKEKB electron-positron collider, aiming to deliver an unprecedented peak instantaneous luminosity to the Belle-II experiment, was operated for the first time at the beginning of this year. The expected luminosity --- 40 times that delivered to the Belle experiment --- demands careful prediction and characterization of the machine-induced background radiation and its effect on the detector. Of particular interest is the prediction of the impacts on the performance and longevity of the electromagnetic calorimeter. To rely exclusively on simulation of the new and unknown SuperKEKB machine for such predictions would be rather daring, therefore the goal of the experiment is to measure the electromagnetic background rate and spectra in the so-called end-cap regions of the calorimeter, where it is predicted to be the largest. We used six calorimeter units each containing three types of crystal scintillators, all read out by photo-multiplier tubes. These units were placed in the forward and in the backward regions of the interaction region, at positions reproducing those of the Belle-II calorimeter end-cap crystals. We record the arrival time and deposited energy for each hit, and the different crystal materials will provide sensitivity to different parts of the spectra. We are taking data since February, during the accelerator commissioning and always changing beam conditions. We want to capture the relationships between the background observables and accelerator quantities such as the bunch size, the beam current, and the pressure in the vacuum chamber. It is the scaling of the background compared to the beam parameters that will enable us to disentangle the dominant physical processes behind observed beam loss events, and test how well each of these processes is simulated. The measurement campaign coincides with the first phase of SuperKEKB commissioning, and is planned to end on June 30th, 2016.
        Speaker: Alexandre Beaulieu (University of Victoria)
      • 2:00 PM
        Search for supersymmetry in final state with jets and two same-sign leptons or three leptons with the ATLAS detector. 15m
        Supersymmetry (SUSY) is one of the most popular and the most studied theory proposed as an extension to the Standard Model (SM). If R-parity is conserved the lightest supersymmetric particle (LSP) is stable and in many models LSP can be a good candidate for dark matter. I will present the method and the results about the search of strongly produced supersymmetric particles using a specific signature involving final states with multiple hadronic jets and either two isolated leptons ($e$ ou $\mu$) with the same electric charge or at least three isolated leptons. This signature is present in many SUSY scenarios and Standard Model processes leading to such final states have a very small cross-section. The analysis uses a data sample of proton-proton collisions at $\sqrt{s}=13$ recorded with the ATLAS detector at the Large Hadron Collider (LHC) in 2015 corresponding to a total integrated luminosity of 3.2 $fb^{-1}$. During the talk, I will cover different aspects of the analysis such as the detector, the dataset and simulated event samples, the event selection, the background estimation (and validation) and finally the results, interpreted in several simplified SUSY models.
        Speaker: Hubert Trepanier (Universite de Montreal (CA))
      • 2:15 PM
        Collecting events based on jet substructure with the ATLAS detector 15m
        The most common feature produced in the proton-proton collisions of the Large Hadron Collider (LHC) are collimated sprays of particles referred to as jets, which are typically produced from quarks or gluons. The large centre-of-mass energy of the LHC collisions also enables the production of heavy particles with a significant Lorentz-boost. The decay products of such a boosted heavy particle can be reconstructed as a single jet, and hence at a first glance, look very similar to the jets produced from quarks and gluons. However, these classes of jets have different internal structure. The study of the internal jet substructure is currently a hot topic within High Energy Physics. A long list of analyses at the LHC exploit features of the radiation pattern within jets to identify jets from heavy boosted objects, often in searches for new physics phenomena. A significant limitations for some of these analyses at the ATLAS experiment is that many of the interesting collision events are never recorded since they are not accepted by the trigger system that filters out the vast majority of collisions only keeping the ones deemed most interesting. This presentation will give an overview of jet substructure used in physics studies of boosted objects with particular emphasis on the development of dedicated, optimized triggers that select data events based on features of the substructure of jets. This has potential to significantly improve the sensitivity of several analyses that search for new physics phenomena.
        Speaker: Mr Nima Sherafati (Carleton University)
    • 1:00 PM 2:30 PM
      M2-6 Theory, Modelling, and Forecasting II (DASP) / Théorie, modélisation et prévisions II (DPAE) Colonel By D103

      Colonel By D103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: patrick perron (RMCC)
      • 1:00 PM
        Harnessing butterflies for climate closure and for improved monthly, seasonal, and interannual forecasts 30m
        Although the butterfly effect – sensitive dependence on initial conditions - fundamental limits deterministic weather forecasting to horizons of about 10 days, it has not prevented deterministic Global Circulation Models (GCM’s) from being used way past this limit for monthly, seasonal and interannual forecasts. When such models are used for these longer term “macroweather” forecasts, they can only be interpreted statistically. However at monthly, seasonal and multiyear (“interannual”) scales, the atmosphere is governed by new (higher level) stochastic (statistical) laws which imply a huge memory which can be directly exploited by the Stochastic Seasonal and Interannual Prediction System (StocSIPS). StocSIPS is a straightforward, highly efficient forecasting system that makes global, monthly, seasonal and interannual forecasts. For these horizons, StocSIPS is significantly more accurate than the conventional models. StocSIPS’ advantages include: * Convergence to the real – not model - climate: The key to StocSIPS skill is the ScaLIng Macroweather Model (SLIMM) forecasting module that uses past data – and the huge memory in the system - to ensure that the forecast converges to the real world climate. * Speed: In order to get good statistics, conventional seasonal to annual forecasts typically re-forecast over ten to twenty realizations, each time using slightly different initial data typically taking the equivalent of a million CPU hours on the world’s fastest computers. In comparison, StocSIPS uses only a few minutes of CPU time to directly calculate the statistics of an infinite number of realizations. * No data assimilation: StocSIPS can directly forecast either gridded or individual station data, there is no need to transform the input data to make it digestible by the numerical model; StocSIPS avoids complex data “assimilation” techniques. * No ad hoc post processing: The raw temperatures and precipitation rates forecast by conventional models have unrealistic variability. This is usually “corrected” using complex ad hoc post processing algorithms that use hindcasts to incorporate past information in order to make the forecasts more realistic. StocSIPS uses only past information with a theoretically justified forecast procedure. * No need for downscaling: Conventional models have pixels of 100,000 km2 or more in size and must be “downscaled” to adapt them to local conditions. Whenever long station temperature series are available, StocSIPS can forecast them directly. Finally, the global temperature – including the “pause” can be accurately forecast and this can be used to show that the probability that the post industrial warming was simply a giant fluctuation is less than 0.1%, thus closing the climate debate.
        Speaker: Shaun Lovejoy (McGill University)
      • 1:30 PM
        The importance of an accurate magnetic field for the estimation of Faraday rotation from total electron content. 15m
        A plane polarized wave that propagates through a plasma, parallel to a magnetic field, suffers a gradual rotation of its plane of polarization called Faraday rotation. Likewise, radio beacon signals that traverse the ionospheric plasma encounter a parallel component of Earths geomagnetic field and the anisotropy of the medium. Many authors use the average value of the parallel magnetic field for estimation of Faraday rotation (FR) from ionospheric total electron content (TEC) measurements. Although it is known that the strength of Earth's geomagnetic field varies slowly at ionospheric altitudes, a reference height characteristic value or reference mean value may not always be sufficient. though commonly used. Numerical modelling has demonstrated that FR, independent of carrier frequency, can be calculated more accurately by applying a weighted average in favour of the ground based values when using an average value of the magnetic field. Values for the electron density from the International Reference Ionosphere (IRI) and magnetic field from the International Geomagnetic Reference Field (IGRF) were sampled for several different days at different latitudes. The TEC was computed from the convolution of the electron densities from IRI and magnetic field values from IGRF. The effect on the conversion of the modelled TEC to FR along vertical paths for different values of the magnetic field, including the average, reference altitude and weighted average. They were compared with the conversion using IGRF as a function of altitude as the ideal solution. For all conditions, an average value for the magnetic field tends to underestimate the degree of FR. This work found that a weighted average in favor of the magnetic field values from lower altitudes improved results.
        Speaker: Alex Cushley
      • 1:45 PM
        The Empirical Canadian High Arctic Ionospheric Model (E-CHAIM): NmF2 and hmF2 specification 15m
        It is well known that the IRI suffers reduced accuracy in its representation of monthly median ionospheric variability at high latitudes (Themens et al. 2014, Themens et al. 2016). These inaccuracies are believed to stem from a historical lack of data from these regions. Now, roughly thirty and forty years after the development of the original URSI and CCIR foF2 maps, respectively, there exists a much larger dataset of high latitude observations of ionospheric electron density. These new measurements come in the form of new ionosonde deployments, such as those of the Canadian High Arctic Ionospheric Network, the CHAMP, GRACE, and COSMIC radio occultation missions, and the construction of the Poker Flat, Resolute, and EISCAT Incoherent Scatter Radars systems. These new datasets afford an opportunity to revise the IRI’s representation of the high latitude ionosphere. For this purpose, we here introduce the Empirical Canadian High Arctic Ionospheric Model (E-CHAIM), which will incorporate all of the above datasets, as well as the older observation records, into a new climatological representation of the high latitude ionosphere. In this presentation, we introduce the NmF2 and hmF2 portions of the model and present a validation of the new model with respect to ionosonde observations in Alert, Canada. A comparison with respect to IRI performance will also be presented.
        Speaker: David Themens (University of New Brunswick)
      • 2:00 PM
        Calculation and Analysis of High Rate Total Electron Content in the Canadian High Arctic 15m
        The Canadian High Arctic Ionospheric Network (CHAIN) [1] includes Global Positioning System (GPS) receivers capable of sampling specific observables at very high rates, up to 100 Hz. With these high rate observables, 100 Hz Total Electron Content (TEC), and Rate of TEC index (ROTI), can be calculated. This study outlines the methods and limitations of calculating both relative and absolute 100 Hz TEC, specifically from the observables provided by the Septentrio PolaRxS Pro GPS. Spectral analyses of the high rate TEC and ROTI is also presented, determining whether important results can be obtained within the higher frequency data. The expected hardware noise is predicted to aid in the determination of important results in the data, in an attempt to extract ionospheric information from possible sources of noise. [1] Jayachandran, P. T., R. B. Langley, J. W. MacDougall, S. C. Mushini, D. Pokhotelov, A. M. Hamza, I. R. Mann, D. K. Milling, Z. C. Kale, R. Chadwick, T. Kelly, D. W. Danskin, and C. S. Carrano (2009), The Canadian high arctic ionospheric network (CHAIN), Radio Sci., 44, RS0A03, doi:10.1029/2008RS004046, 2009.
        Speaker: Anthony McCaffrey (University of New Brunswick)
      • 2:15 PM
        A Neural Network (NN)-based foF2 model for a single station in the polar cap 15m
        The work on neural networks (NN) by several authors has shown promising results in modeling nonlinear and complex processes in the near Earth space. For instance, NN-based models have been developed to forecast solar and magnetic activity indices, and different ionospheric parameters. However, the developed models have been faced with the challenge of data paucity in the polar region, a major drawback in obtaining suitable relevant models for various geophysical applications in the region. A neural network based model for the critical frequency of the F2 layer (foF2) has been developed using selected geophysical inputs and observed data from Resolute (74.75° N, 265.00° E) spanning from 1975 – 1995 and 2009 – 2012, obtained from the Space Physics Interactive Data Resource (SPIDR) and the Canadian High Arctic Ionospheric Network (CHAIN), respectively. A comparison between the NN and the IRI (International Reference Ionosphere) model values with observations was investigated. Both models reproduce the observed diurnal and seasonal variations in foF2 except that the IRI model tends to underestimate the values during low solar activity. The NN model is able to reproduce the enhancements in the foF2 observed in the measurements during the equinoxes, and also shows an improvement in foF2 predictions during disturbed days. An analysis of the root mean square errors (RMSE) computed between the model predictions and observed values show a noticeable margin between the NN and IRI – predicted foF2 values.
        Speaker: Racheal Athieno (University of New Brunswick)
    • 1:00 PM 2:30 PM
      M2-7 Carbon-based Nanomaterials (DCMMP-DSS) / Nanomatériaux à base de carbone (DPMCM-DSS) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Rafik Naccache (Concordia University)
      • 1:00 PM
        2D Materials Growth: Applications and Challenges 30m
        Two-dimensional (2D) materials have attracted much attention due to their unique properties. Controllable synthesis of 2D materials with high quality and high efficiency is essential for their large-scale applications. In parallel to the chemical synthesis route, chemical vapor deposition (CVD) has been one of the most important techniques for the synthesis of 2D materials. The present talk will be devoted to the CVD growth of graphene, boron nitride, core-shell nanoparticles@graphene and transition metal dichalcogenides (TMDs) in our research group. The Hydrogen-induced effects during the growth will be discussed. In parallel, we will show that the use of these resulting 2D materials as electrodes leads to an enhancement of the overall reactivity and sensors sensitivity which is favorable for many applications.
        Speaker: Prof. Mohamed Siaj (UQAM)
      • 1:30 PM
        Terahertz Response of Monolayer Graphene:Velocity Gauge Vs Length Gauge 15m
        Graphene, as a zero-bandgap two-dimensional semiconductor with a linear electron band dispersion near the Dirac points has potential to exhibit very interesting nonlinear optical properties [1]. In particular, third harmonic generation of terahertz (THz) radiation should occur both due to the nonlinear relationship between the crystal momentum and the current density, and due to the interaction between interband and intraband parts of the current densities due to the vanishing bandgap [2]. In this work, we investigate two different ways of calculating the nonlinear response of graphene to THz radiation. There are two different gauges that are commonly employed to study the interaction of electrons in a semiconductor with a THz or optical field: the velocity gauge and the length gauge [3,4] In the length gauge, the interaction of the electrons with the field is given by $\vec{r}\cdot\vec{E(t)} $, while in the length gauge, it is given by $\vec{p}\cdot\vec{A(t)} $. In this work, we derive the nonlinear density matrix equations and current density expressions in the two gauges for graphene in a two band model. We show that if one uses the mass sum rule for the bands, the two methods yield very similar linear conductivities. However, we find that the nonlinear response can be quite different for the two approaches, due in large part to the divergences that arise at zero frequency in the velocity gauge when one uses a basis with a finite number of bands. We conclude that one should use the the length gauge for graphene when calculating the nonlinear THz response. References: [1] S. A. Mikhailov, Phys. Rev. Lett. \textbf{105} ,097401 (2010). [2 ]I. Al-Naib, J. E. Sipe, M. M. Dignam, Phys. Rev. B \textbf{90 }, 245423 (2015). [3] A. Chacona , M. Lewensteina,b, M. F. Ciappina,Journal of Computational Physics. \textbf{1 },1508.04889 (2015). [4] I. Al-Naib, J. E. Sipe, M. M. Dignam, New J. Phys. \textbf{17 }, 113018 (2015).
        Speaker: Parvin Navaeipour (Queen's University)
      • 1:45 PM
        Spontaneous polarization of the two-dimensional electron gas in WS$_2$ 15m
        Tungsten disulfide represents a class of 2D materials, transition metal dichalcogenides (TMDC), which exist as layers of atomic thickness with atoms organized in a honeycomb lattice. Similarly to graphene, in TMDCs the minimum of the conduction band and the maximum of the valence band are found at the K and K’ points in the Brillouin zone. Unlike graphene, these systems exhibit (i) a large direct bandgap, and (ii) strong spin-orbit interaction, which locks the spin and valley degrees of freedom of quasielectrons and quasiholes. The two-dimensional character of TMDCs results in a significant enhancement of Coulomb interactions. In Hartree-Fock (HF) approximation, this leads to a spontaneous valley polarization of the two-dimensional electron gas (2DEG) driven by electron-electron exchange. The valley polarization translates into spontaneously circularly polarized emission recently detected in magnetooptical measurements [1]. We present here a microscopic theory of the two-dimensional electron gas in WS$_2$ . We develop an atomistic tight-binding (tb) model for single-quasielectron and quasihole states accounting for the spectral content of the subbands in terms of linear combinations of atomistic orbitals. The tb parameters are obtained from ab-initio calculations. The spin-orbit coupling and resulting reversal of the spin order of the conduction band are treated phenomenologically. This allows to formulate the optical selection rules and calculate Coulomb interaction matrix elements atomistically. Using these elements, we calculate the HF phase diagram of the system of N interacting electrons in doped WS$_2$ and demonstrate the formation of a valley polarized 2DEG state for low enough electronic densities, and a valley-singlet state for larger densities. The effect of correlation and Q minima are also included. The effect of a magnetic field is discussed in terms of Landau levels of interacting massive Dirac Fermions. Finally, we relate the formation of the valley polarized state with magnetooptical experiments. [1] T. Scrace, Y. Tsai, B. Barman, L. Schweidenback, A. Petrou, G. Kioseoglou, I. Ozfidan, M. Korkusinski, and P. Hawrylak, Nature Nanotechnology 10, 603 (2015).
        Speaker: Dr Marek Korkusinski (National Research Council)
      • 2:00 PM
        Contactless thermal conductivity imaging in nanoscale semiconductors 15m
        Pulsed thermoreflectance (PTR) and photothermal deflection spectroscopy (PDS) are powerful and contactless methods to simultaneously determine the thermal diffusivity and thermal conductivity of thin solid films. In PTR, the heat generated in an optically absorbing thin film by a pulsed and monochromatic light beam creates a change of reflectance in the material, which is detected via a lock-in amplifier. In PDS, the heat generated in the thin film diffuses through a transparent photothermal fluid in which the film is embedded and the thermal gradient experienced at the interface between the film and the adjoining fluid can be probed by a laser beam grazing the film surface and periodically deflected away from the surface by modulated changes of refractive indexes at the interface. In both PTR and PDS, the phase and amplitude of the signals are measured using position-sensitive photodetectors. From the two measured parameters, phase and amplitude, the thermal diffusivity and thermal conductivity of the sample can be simultaneously inferred without any needs of contacts on the thin film sample. Consequently, the thermal properties investigated in this way are not dependent on interface effects between the solid and metallic contacts. We demonstrate that PTS and PDS are also capable of mapping the thermal properties of thin films at the microscopic level and beyond, if PTS and PDS are coupled with a system comprising two optical microscopes, an upright optical microscope, in which pulsed monochromatic light is focussed, and an inverted optical microscope from which the signal is probed and detected. This setup will be used for imaging the thermal properties of thin films that are composite at the nanoscale and will include collections of graphene flakes on glass and polymer-fullerene blends for organic photovoltaic applications. In case of graphene flakes on glass, different interface thermal resistivities can be observed for different types of edges, armchair and zigzag. The ultimate resolution of our imaging techniques will be discussed as well.
        Speaker: Mr Sina Kazemian (PhD student)
    • 2:45 PM 3:15 PM
      M-MEDAL CAP Medal Talk - Roger Melko, U. of Waterloo / Perimeter Institute (CAP Herzberg Medal Recipient / Récipiendaire de la médaille Herzberg de l'ACP) Marion 150

      Marion 150

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
      • 2:45 PM
        The Information Age in Condensed Matter Physics 30m

        Monte Carlo simulations have been ubiquitous in efforts to simulate and characterize properties of matter and materials since the advent of computers themselves. In the last decade, condensed matter physicists have turned simulation technology to the study of a new set of phenomena, loosely termed as "emergent", with correlations not manifested in traditional correlation functions. Motivated by this, a new set of tools was recently developed that allows one to probe emergent phenomena in Monte Carlo simulations through their entanglement entropy - a concept borrowed from quantum information theory. Remarkably, since certain scaling terms in the entanglement entropy are universal, this provides a powerful general method to characterize phases and phase transitions in a wide variety of physical theories. Thus, Monte Carlo simulations are beginning to play a central role for physicists who increasingly rely on information quantities to study correlations not only in condensed matter systems and quantum devices, but even in quantum fields and theories of quantum gravity.

        Speaker: Prof. Roger Melko (University of Waterloo)
    • 3:15 PM 3:45 PM
      Health Break / Pause santé
    • 3:45 PM 5:30 PM
      CAP-NSERC Liaison Cttee Mtg / Réunion du comité de liaison ACP-CRSNG Colonel By A707A

      Colonel By A707A

      University of Ottawa

      Convener: Bill Whelan (University of Prince Edward Island)
    • 3:45 PM 5:15 PM
      M3-1 Nuclear Astrophysics (DNP) / Astrophysique nucléaire (DPN) Colonel By B205

      Colonel By B205

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Barry Davids (TRIUMF)
      • 3:45 PM
        Neutron star mergers: neutrino emission and nucleosynthesis 30m
        Neutron-star binary mergers are interesting for several reasons: they are proposed as the progenitors of short gamma-ray bursts, they have been speculated to be a site for the synthesis of heavy elements, and they emit gravitational waves possibly detectable at terrestrial facilities. Our current understanding of the merger evolution and the production of new elements is linked to details of nuclear physics and gravity. In particular, a key ingredient is the neutrino emission which is subjected to a strong gravitational field and influences the matter neutron-richness. In this talk, I shall discuss some aspects of the binary system evolution and the impact of neutrinos on the synthesis of elements.
        Speaker: Olga Caballero
      • 4:15 PM
        Constraining neutron capture rates far from stability and astrophysical implications 30m
        The astrophysical r-process is responsible for the synthesis of about half of the isotopes of the heavy elements. Despite its well-known role in nucleosythesis, the astrophysical site where it takes place has not been unambiguously determined. Efforts for the better understanding of this important process span across many fields, from astronomical observations of metal-poor stars, and modeling of the possible scenarios, to sensitivity studies to input parameters, nuclear theory calculations and nuclear experiments. The present talk will focus on the experimental efforts for providing nuclear input information to help improve our understanding of the r-process. One of the important inputs, that is practically unconstrained by experiment, is neutron capture reactions. The talk will focus on the development of a new technique (β-Oslo) to experimentally constrain these important (n,γ) reaction rates far from stability. The experiments were done at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University using the γ-calorimeter SuN. The validation of the β-Oslo technique, first physics results and implications for astrophysical calculations will be presented.
        Speaker: Artemis Spyrou (Michigan State University)
      • 4:45 PM
        **WITHDRAWN** Phase-imaging mass measurements with the Canadian Penning trap mass spectrometer 15m
        Roughly half of the elements heavier than iron are thought to be produced through the astrophysical rapid-neutron capture process of nucleosynthesis. Despite its large influence in explaining the observed abundance of heavy elements, much of the *r* process is still poorly understood. A more thorough library of nuclear data, particularly masses, of neutron-rich nuclei is needed to improve the accuracy and progression of r-process calculations. The Canadian Penning trap mass spectrometer (CPT) is currently located in the CARIBU facility at Argonne National Laboratory where intense radioactive beams of neutron-rich nuclei are produced from the spontaneous fission of $^{252}$Cf. Since its move to CARIBU in 2010, the CPT has successfully measured the masses of more than 110 isotopes to a typical precision of 15 keV/c$^2$ by measuring the cyclotron frequency of ions through a time-of-flight (TOF) technique. An upgrade to a position-sensitive microchannel plate detector at the CPT has facilitated a contemporary technique in the determination of masses by measuring the phases of orbital motion of trapped ions. This phase-imaging method is intrinsically more efficient than the TOF technique, and provides an order of magnitude improvement in mass-resolving power without loss in precision, allowing access to more weakly produced isotopes with shorter half-lives than was previously achievable at CARIBU. The low-energy beamline at CARIBU was recently fitted with a multi-reflection time-of-flight mass separator (MR-TOF) which improved beam purity by more than an order of magnitude. In a preliminary measurement campaign the phase-imaging technique, buoyed by the MR-TOF, has yielded the masses of eight previously unmeasured ground-state rare-earth isotopes, and another three nuclear isomers whose masses were directly measured for the first time. These results and future plans to probe another 1-3 neutrons from stability will be discussed.
        Speaker: Rodney Orford (McGill University)
      • 5:00 PM
        Decay Spectroscopy of Neutron-Rich Cd Around the N = 82 Shell Closure 15m
        The neutron-rich region around A = 132 is of special interest for nuclear astrophysics and nuclear structure. From an astrophysics perspective, this region is connected with the second r-process abundance peak at A$\approx$130 and the waiting-point nuclei around N = 82. For nuclear structure studies, the neighbours of the doubly-magic $^{132}$Sn (Z = 50, N = 82) are an ideal test ground for shell model predictions. The beta-decay of the N = 82 isotope $^{130}$Cd into $^{130}$In was first investigated a decade ago, but the information for states of the lighter indium isotopes ($^{128,129}$In) is still limited. In the present experiment, a detailed gamma-spectroscopy of the beta-decay of $^{128-132}$Cd was achieved with the newly commissioned GRIFFIN (Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei) gamma-ray spectrometer, which is capable of measuring down to rates of 0.1 pps. The low-energy cadmium isotopes were implanted into a movable tape at the central focus of the array from the ISAC-I facility at TRIUMF. The beta-tagging was performed using the auxiliary beta-particle detector SCEPTAR. The required beta-gamma(-gamma) coincidence data in high statistics needed to fill the spectroscopic gaps described in literature were obtained. Timing information needed to measure the half-lives of $^{128-130}$Cd was collected to resolve previously published discrepancies in those values. The ongoing analysis of these data will be presented.
        Speaker: Nikita Bernier (TRIUMF)
    • 3:45 PM 5:15 PM
      M3-2 Atomic and Molecular Spectroscopy and Precision Measurements II (DAMOPC) / Spectroscopie atomique et moléculaire et mesures de précision II (DPAMPC) Colonel By D207

      Colonel By D207

      University of Ottawa

      Convener: Dr Amar Vutha (University of Toronto)
      • 3:45 PM
        Welcome to the New Age: Realization of an Ultra-Accurate, Single Ion Clock at the Quantum Mechanical Stability Limit 30m
        There is now a revolution underway in ultra-accurate measurements of frequency and time using optical atomic transitions probed with highly coherent laser light. By suspending a single atomic ion using an electro-dynamic trapping field and reducing its velocity by laser cooling, we can approach, as close as possible, the ideal situation of an isolated and unperturbed quantum system. Laser sources that probe the atom can now be made so spectrally pure that they can be used as phase-stable sources of electro-magnetic radiation. In addition, the use of femtosecond laser technology now enables us to continuously measure the cycles of light from the reference and provide a working standard for time. Using such powerful methods, our team has realized an optical atomic frequency/time reference at 445-THz (674 nm) based on a single atomic ion of strontium. This talk will overview some of the exciting concepts making up such experiments and will include evaluated accuracies of this system (at 1.2 × 10$^{-17}$ fractional uncertainty) that exceed by over a factor of ten the best current realizations of the definition of the SI second. Recently, we have demonstrated that such a single ion frequency standard can reach the level of stability limited by the principles of quantum mechanics. At this level of accuracy and stability, it is now possible to measure the distortion of local time due to Earth’s gravitational field by changes of the clock height at the sub-meter level. Further refinement of the systematic shift evaluation promises to bring the evaluated uncertainty down into the 10$^{-18}$ fractional uncertainty level. Some observations will be made as to what we expect these new generation optical clocks to yield in terms of the redefinition of the SI unit second, probing nature’s weakest force (gravity), and other sensitive tests of Physics.
        Speaker: Prof. Alan Madej (NRC/ MSS, York University, University of Ottawa)
      • 4:15 PM
        Ro-Vibrational Emission Spectra of DCN Revisited 15m
        We present a study of the infrared emission spectra of Deuterium Cyanide (DCN) in the 450 to 850 wavenumbers range at 1370 K. Hydrogen Cyanide (HCN) was present as an impurity in the sample. The spectra were recorded using a Fourier transform spectrometer Bruker IFS 120 HR at the Justus-Liebig Universität, Giessen, Germany. A spectrum analysis software called SyMath developed by one of the authors (G. Mellau) was used to analyze the spectra and obtain improved spectroscopic constants. We report the ro-vibrational constants for the DCN molecule and compare them with a previous study published by E. Mӧllmann *et al*. [1] in 2002. REFERENCES 1. E. Mӧllmann, A. G. Maki, M. Winnewisser, B. P. Winnewisser, W. Quapp, J. Mol. Spectrosc. 212, 22–31 (2002).
        Speaker: Prof. Adriana Predoi-Cross (Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB, T1K 6R4 Canada)
      • 4:30 PM
        The Oxygen A-Band Spectra Revisited 15m
        We have re-analyzed the A-band spectra of oxygen and oxygen broadened by nitrogen previously published by our research group [1,2]. We have used a multispectrum fit analysis [3] and different line shape models. The line shape narrowing (Dicke) effects were incorporate using theoretical calculations for the self diffusion coefficients and Maxwell–Stefan diffusion coefficients discussed. We have compared our re-analysis results with published results available in the literature. REFERENCES 1. A. Predoi-Cross, C. Holladay, H. Heung, J.-P. Bouanich, G.Ch. Mellau, R. Keller, D.R. Hurtmans, Nitrogen-broadened lineshapes in the oxygen A-Band: experimental results and theoretical calculations, J. Mol. Spectrosc. 251 (2008) 159-175. 2. A. Predoi-Cross, K. Hambrook, R. Keller, D. Hurtmans, C. Povey, H. Over, G. Mellau, Spectroscopic Lineshape Study of the Self-Perturbed Oxygen A-Band, J. Mol. Spectrosc. 248 (2008) 85-110. 3. 1. D.C. Benner, C.P. Rinsland, V. Malathy Devi, M.A.H. Smith, D. Atkins,A multispectrum nonlinear least squares fitting technique, J. Quant. Spectrosc. Rad. Transfer 53(6) 705-721 (1995).
        Speaker: Prof. Adriana Predoi-Cross (Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB, T1K 6R4 Canada)
      • 4:45 PM
        FTIR Synchrotron Spectroscopy of the Lower Vibrational Modes of Methyl Mercaptan at the Canadian Light Source 15m
        The Fourier transform infrared spectra of the lower infrared vibrational bands of CH$_{3}$SH have been investigated from 650 to 1200 cm$^{-1}$ at 0.001 cm$^{-1}$ resolution employing synchrotron radiation at the Canadian Light Source in Saskatoon. The relative band strengths and structures are remarkably different from those for the analogous CH$_{3}$OH relative, with the CSH bend being very weak and both the in-plane and out-of-plane CH$_{3}$ rocks being strong with comparable intensities. The CSH bend has parallel $a$-type character with no detectable $b$-type component. The out-of-plane CH$_{3}$ rock is a purely $c$-type perpendicular band, whereas the in-plane rock around is of $a$/$b$ character. The $K$-reduced $v_{t}$ = 0 sub-state origins for the CSH bend follow the normal oscillatory torsional pattern as a function of $K$ with an amplitude of 0.362 cm$^{-1}$, as compared to 0.653 cm$^{-1}$ for the ground state and 0.801 cm$^{-1}$ for the C-S stretching mode. The torsional energy curves for the out-of-plane rock are also well-behaved but are inverted, with an amplitude of 1.33 cm$^{-1}$. In contrast, the sub-state origins for the in-plane rock do not display a clear oscillatory structure but are scattered over a range of about 2 cm$^{-1}$, with indications of some significant perturbations. Our sub-band assignments extend up to about $K$ = 10 for all the modes and are well-determined from GSCD relations, particularly for the $a$/$b$ in-plane rock for which $\Delta$$K$ = 0, +1 and $-$1 transitions are all observed.
        Speaker: Dr Ronald M. Lees (Physics Dept., University of New Brunswick)
    • 3:45 PM 5:15 PM
      M3-3 Fields and Strings (DTP) / Champs et cordes (DPT) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Luc Marleau (Université Laval)
      • 3:45 PM
        Induced False Vacuum Decay by Topological Solitons 30m
        We review our work concerning the decay of the false vacuum by quantum tunnelling transitions. When the false vacuum manifold is non-trivial, it can lock in topological defects. We have considered the possibility that these are magnetic monopoles, cosmic strings, domain walls and most recently, Skyrmions. In all of these cases, the topological defect must realize the true vacuum inside its core. The dynamics generically traps the true vacuum in the core of the defect in a meta-stable state which is unstable to quantum tunnelling transitions. The transition typically inflates the core region until the region of true vacuum is large enough to inflate without restriction. We show how to compute the corresponding instanton and the decay rate using the path integral. Our analysis can be applied to phase transitions in cosmology within the context of field and string theory but also to condensed matter systems.
        Speaker: Manu Paranjape (Université de Montréal)
      • 4:15 PM
        Conformal Bootstrap in Embedding Space 15m
        We show how to obtain all conformal blocks from embedding space with the help of the operator product expansion. The minimal conformal block originates from scalar exchange in a four-point correlation functions of four scalars. All remaining conformal blocks are simple derivatives of the minimal conformal block. With the help of the orthogonality properties of the conformal blocks, the analytic conformal bootstrap can be implemented directly in embedding space, leading to a Jacobi-like definition of conformal field theories.
        Speaker: Prof. Jean-Francois Fortin (Laval University)
      • 4:30 PM
        Relativistic quantum reference frames 15m
        Progress in physics, from Aristotelian physics, to Galilean and Newtonian physics, and then to both special and general relativity, can be viewed as a continual refinement of the notion of a reference frame. The next natural step in this progression is the idea of a quantum reference frame. In this talk, I will introduce the basic tools that have been developed to study quantum reference frames and examine how they may be applied to relativistic scenarios. In particular, I will look at how two observers in different Lorentz frames that are partially correlated can communicate via the exchange of a single massive spin-1/2 particle. I will then construct an alternative approach to quantum reference frames involving a trace over global degrees of freedom, rather than an average over all possible orientations of a system with respect to an external reference frame. This approach is anticipated to help deal with reference frames associated with non-compact groups, such as the Galilean group and Poincare group.
        Speaker: Alexander Smith (University of Waterloo)
      • 4:45 PM
        Quantum tunneling of Fermions from Black Strings 15m
        In this work I would like to give semi-classical derivation of Hawking temperature from cylindricaly symmetric charged rotating black strings. I will use Hamilton Jacobi method and WKB approximation to get analytic expression for Hawking temperature of fermions tunneling from charged black strings.
        Speaker: Mr Jamil Ahmed (Quaid-i-Azam University, Islamabad)
      • 5:00 PM
        Constraints on the spectrum of W algebras 15m
        A conformal field theory is a quantum field theory whose symmetries are extended from the Lorentz group to the conformal group, thus putting more constraints on the theory than what we normally have in regular quantum field theory. In 2 dimensions, the conformal symmetries are infinite dimensional so it is easier to characterize the properties of 2d CFTs than it is in higher dimensions. Extensions of these symmetry algebras that include higher spin generators in addition to the energy-momentum tensor have been built a long time ago and they have found applications in string theory, statistical mechanics and holography. In this talk I will discuss a way of constraining the spectrum of operators in unitary representations of these so called W algebras. In particular, I will study the W(2,4) algebra, which has an extra spin 4 generator, and I will search for representations with negative norm states. This will give various new constraints on the scaling dimensions and charges of the states in the theory. This kind of results can be translated to higher spin theories of gravity using the AdS/CFT correspondence and give new insights on the allowed theories.
        Speaker: Yan Gobeil (McGill University)
    • 3:45 PM 5:15 PM
      M3-4 Materials Characterization: Microscopy and Imaging (DCMMP) / Caractérisation des matériaux: microscopie et imagerie (DPMCM) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Dr Arun Ramchandran (University of Toronto)
      • 3:45 PM
        Colloidal systems for smarter cancer imaging and adaptive therapy 30m
        Imaging is a fundamental tool in the practice of medicine. The interaction of medical imaging radiation with new materials has long been exploited to develop new and improved imaging systems and techniques. In parallel with these advances, there is increasing interest in developing new contrast agents for the diagnosis of disease. Exogenous contrast agents are non-native sources of contrast that differentially scatter, absorb, or emit medical imaging radiation (e.g., sound waves for ultrasound imaging, radiofrequency waves for magnetic resonance imaging, near IR light for photoacoustic imaging, and x-rays for computed tomography and mammography) as compared to surrounding tissues and inherent background noise such that their location can be tracked upon introduction into a patient. At the forefront of new contrast agent development are new, clinically-relevant, colloidal materials that can be activated by medical imaging radiation external to the patient and under image guidance, to characterize and treat cancer. Since the contrast agents’ *in vivo* distribution and interaction with radiation are strongly size- and material-dependent, a new opportunity in materials science is the creation of new colloidal systems that can be tailored for specific contrast imaging and with therapeutic properties. This talk will focus on the development of new contrast agents that can facilitate more focused and targeted delivery of cancer therapies to tumours for higher therapeutic ratios, and can permit the treatment of hard-to-access organs like the brain in a minimally-invasive manner. Specific examples of different hierarchical and composite contrast agents that are assembled to address and balance biological and physical challenges of contrast agent development will be given, with a focus on the use of perfluorocarbon bubbles, droplets and nanoparticles as multifunctional contrast agents for ultrasound imaging and therapy applications.
        Speaker: Naomi Matsuura (University of Toronto)
      • 4:15 PM
        Magnetic Dipole-Dipole Sensing at the Atomic Scale 15m
        High-resolution magnetometry is an essential tool used across the sciences. The recent development of electron spin resonance scanning tunnelling microscopy (ESR-STM) opens the door on a new type of magnetometry, one with the ability to coherently manipulate quantum spins with neV energy resolution and sub-nanometre spatial resolution [1]. In this talk I will show recent results obtained from ESR-STM experiments of Fe and Co atoms deposited on an MgO thin film. By characterizing the magnetic dipole-dipole interaction between atoms we are able to determine their magnetic moment to within 40 neV [2]. Combining this energy resolution with the STM's ability to manipulate atoms we then create and characterize the properties of magnetic nanostructures. Lastly, I will discuss the development of a pulsed ESR-STM scheme and it's relevance for future experiments in quantum computing and quantum simulation. [1] S. Baumann, W. Paul, T. Choi, C.P. Lutz, A. Ardavan, and A.J. Heinrich, Science 350, 417 (2015) [2] T. Choi et al., in preparation
        Speaker: Mr Andrew Macdonald (University of British Columbia)
      • 4:30 PM
        "Macroporous Silicon as an IR Filter" 15m
        Authors: T. Beniac, C. Vendromin, N. Dwyer, N. Majtenyi, M. Reedyk. Currently, optical cutoff filters in the infrared range are primarily based on scattering or multilayers. These types of filters, however, come with disadvantages. In multilayer filters the varying material properties between the different layers causes mechanical instability at extreme temperatures. Scattering-type filters can be very fragile; the filters may be damaged by exposing them to high pressure gradients or by accidental mechanical removal of the scatterers. It has recently been found that macroporous Silicon can act as an optical cutoff filter in the infrared range.[1] Filters constructed from porous Silicon do not exhibit the same disadvantages as do the scattering and multilayer filters. Macroporous Silicon is created via an electrochemical etching process using an anodic (i.e. the Silicon sample acts as the anode) electrochemical cell containing an electrolyte solution of hydrofluoric acid and ethanol. When a current is passed across the cell, it is observed that pores form on the surface of the sample over time. The morphological properties of these pores seem to differ depending on etching conditions such as the concentration of acid in the electrolyte, the electronic and crystallographic properties of the sample, the current, and the etching time. The cutoff wavelength of the porous silicon filters appears to be dependent on the morphological properties of the sample. Silicon samples of differing resistivity and crystal orientation have been etched under various conditions in order to perform a systematic investigation of the relationship between the optical and morphological properties of porous Silicon filters. The cutoff wavelength of the filter is determined by transmission spectroscopy while the morphological properties are investigated by SEM imaging to extract the pore-to-area density of the samples. [1] V. Kochergin, and H. Foell, `Novel Optical Elements Made From Porous Si', Materials Science and Engineering, R 52, (2206) 93-140.
        Speaker: Thomas Beniac (Brock University)
      • 4:45 PM
        Imaging and Temperature Sensing using Submillimeter Radiation 30m
        In recent years, nanomaterials have garnered significant attention in the effort to develop novel applications and technologies, or for the improvement of already existing ones. In particular, a strong emphasis has been placed on nanoparticle-based probes than can be used in imaging and therapeutics. Of particular interest are metal nanoparticles such as silver, platinum and gold, which following resonant excitation with light, show a surface plasmon resonance effect. An interesting by-product of this effect is the transfer of energy to the environment in the form of heat. This typically increases the temperature of a system and finds interesting applications particularly in photothermal therapy. We have used gold nanoparticles as “contrast agents” in combination with terahertz radiation to develop a contact-free approach for heating, temperature sensing and imaging. More specifically, we exploit the change in the refractive index of water, induced by localized NIR heating of plasmonic nanostructures. The latter, namely gold nanorods, were prepared using a conventional bottom up seed-mediated technique. We observe a linear relationship correlating change in the reflected terahertz amplitude and area under the curve as a function of increasing temperature. This was translated to a thermometric relationship allowing for temperature sensing following an induced heat stimulus. We extended our results to the porcine skin model system in order to mimic the photothermal effect and demonstrated the capacity to sense the temperature and map its distribution in the localized injection site, following controlled NIR plasmonic heating. As a result, we have developed a terahertz biological thermometer.
        Speaker: Prof. Rafik Naccache (Concordia University)
    • 3:45 PM 5:15 PM
      M3-5 Cosmic frontier: Dark matter I (PPD) / Frontière cosmique: matière sombre I (PPD) MacDonald 146

      MacDonald 146

      University of Ottawa

      Convener: Dr Ian Lawson (SNOLAB)
      • 3:45 PM
        Recent Results and Future Plans for Dark Matter Searches with PICO 30m
        The PICO experimental program at SNOLAB uses superheated bubble chambers to search for evidence of dark matter primarily through spin-dependent interactions on 19F in C3F8. Recoiling nuclei from WIMP-nucleon interactions in the active fluid deposit enough energy locally to initiate a phase transition in the fluid. The bubbles which form are observed with stereo cameras and their acoustic signature is recorded by sensitive piezo-electric transducers. By controlling the degree of superheat, the detector can be made insensitive to gamma and electron backgrounds. Alpha particles with relatively longer tracks have a distinctly different acoustic signal when compared to nuclear recoils which enables this background to be identified and discriminated against. The recent results from the PICO collaboration will be presented, along with an outlook for the future program with this unique technology.
        Speaker: Tony Noble (Queen's University)
      • 4:15 PM
        Study and Development of Pulse-shape Discrimination Firmware for Background Mitigation in the DEAP-3600 Experiment 15m
        DEAP-3600 is particle detector looking for weakly interacting massive particles (WIMPs) as a source of dark matter. Incident particles colliding with the 3600 kg argon target in DEAP will produce excited dimers which decay releasing scintillation light. The proportion of singlet and triplet excited states of the dimers produced depends on the interacting particle type, with the result that events can be characterized by the timing distribution of the scintillation light. The intrinsic Ar-39 in natural argon produces approximately 1 Hz/kg of beta decays. To reduce the background rate from beta decay, the DEAP trigger removes a proportion of these events. It is crucial that potential WIMP events and rare background events are not miscategorized as beta decays by the trigger, and thus the trigger calibration is essential to achieve the dark matter sensitivity goal of the experiment. This talk will explain the trigger algorithm, its parameters, and present results from the trigger calibration.
        Speaker: Mr Simon Norman-Hobbs (TRIUMF)
      • 4:30 PM
        **WITHDRAWN** Application of Wavelength Shifter to the Acrylic Vessel in the DEAP-3600 Dark Matter Search 15m
        DEAP-3600 is a single phase liquid argon dark matter search experiment. The target consists of 3600 kg of liquid argon, contained in a spherical acrylic vessel and viewed by a surrounding array of photomultiplier tubes (PMTs). Particle interactions in liquid argon produce scintillation light in the vacuum ultraviolet (VUV) spectrum, which is efficiently absorbed by the surrounding acrylic. To make interactions in the target volume visible to the PMTs, the inner surface of the acrylic sphere was coated with the organic wavelength shifter, 1,1,4,4-tetraphenyl-1,3-butadiene (TPB), which has a re-emission spectrum for VUV light in the blue-visible regime. During the final stage of construction, a 3 micrometer thick coating of TPB was applied to the vessel's inner surface using vacuum deposition. This talk will present details on the final deposition, thickness considerations, and ex-situ sample analysis results.
        Speaker: Benjamin Broerman (Queen's University)
      • 4:45 PM
        Improved dark matter search results from PICO-2L Run 2 15m
        New data are reported from a second run of the 2-liter PICO-2L $C_3F_8$ bubble chamber with a total exposure of 129 kg-days at a thermodynamic threshold energy of 3.3 keV. These data show that the measure taken to control particulate contamination in the superheated fluid resulted in the absence of the anomalous background events observed in the first run of this bubble chamber. One single nuclear-recoil event was observed in the data, consistent both with the predicted background rate from neutrons and with the observed rate of unambiguous multiple-bubble neutron scattering events. The chamber exhibits the same excellent electron-recoil and alpha decay rejection as was previously reported. These data provide the most stringent direct detection constraints on weakly interacting massive particle (WIMP)-proton spin-dependent scattering to date for WIMP masses < 50 GeV/c$^2$.
        Speaker: Chanpreet Amole (Queen's University)
      • 5:00 PM
        **WITHDRAWN** Two-Hit and Two-Track Resolution of a Micromegas TPC with a Resistive Layer Including the Effects of Charge Induction 15m
        The Time Projection Chamber (TPC) for the International Linear Collider (ILC) will need to measure about 200 track points with a spatial single-hit resolution close to 100 microns. A Micro Pattern Gas Detector (MPGD) readout TPC with a resistive layer can achieve the desired resolution. A new readout technique using the principle of charge dispersion with a resistive layer on a Micromegas has indeed demonstrated that the single-hit transverse and longitudinal resolution goals have been met. The next step of the R&D for a TPC at the ILC is concerned with two-hit and two-track separation. In this presentation, a detailed simulation of two-hit and two-track resolution study will be presented. Previous simulations of the ILC TPC have not taken into account the induction of charge on the neighboring readout pads caused by the electrons when they traverse the induction region. The goal of this project is to build and run simulations that take the complete charge induction signals convoluted with the resistive layer response into account for the calculation of the bias correction and pad response function required for a detailed reconstruction of tracks at the ILC TPC.
        Speaker: Roger Odell (Carleton University)
    • 3:45 PM 5:15 PM
      M3-6 Computational Biophysics: Methods and Concepts (DPMB) / Biophysique numérique : méthodes et concepts (DPMB) Colonel By B012

      Colonel By B012

      University of Ottawa

      Convener: Francis Lin (University of Manitoba)
      • 3:45 PM
        Finding the rules of blood regeneration 30m
        Much of complex biology results from interactions among a large number of individually simpler elements. Blood regeneration is no different. About 100 billion new blood cells are made everyday from a much smaller yet a large population of diverse stem cell population. I will present a phenomenological model of blood regeneration, which provides a framework to understand large variation (~3 orders of magnitude) among contributions from individual stem cells observed in recently reported experiments with primates. We show that a combination of slow stem cell differentiation to progenitor followed by their bursty amplification is at the heart of this observed variability. With our model we develop a counter hypothesis to the role of cell-level differences as an explanation for the large variability and highlight the role of progenitors in maintaining blood homeostasis.
        Speaker: Prof. Sidhartha Goyal (Univ of Toronto)
      • 4:15 PM
        Computer Simulation Model of Polymorphisms of Beta-Amyloid Crystals 15m
        Research has established a strong link between symptoms of Alzheimer's disease (AD) to 36-43 amino acid residues peptides, called the amyloid beta (A$\beta$) peptides. Patients with AD are usually diagnosed with aggregates of A$\beta$ peptides, also called plaques, which can be as large as several $\mu$m. The structures of the plaques display a wide variety of polymorphisms that depends on the environments, and are very difficult to reproduce in experiments. This has greatly hindered the efforts to discover the microscopic origin of AD. Recently, Eisenberg *et al.* (Proc Natl Acad Sci USA, 108, 16938-16943, 2011) resolved the structures of segments of A$\beta$ of 5 to 10 amino acid residues. The crystals are very stable, and display a complex polymorphisms of stacked parallel and anti-parallel $\beta$-sheet that may be in-register or out-of-register. At this point over 20 micro-crystals have been identified, and in many cases the same segment of A$\beta$ can form several structures. This submission considers an all-atom simulation model that uses an interaction force field based on the Eisenberg's crystal structures. In the spirit of Go models of folding of single proteins, the force field biased the peptides to the micro-crystal structures, but also exploit the symmetry of the crystals.The model has two adjustable parameters: the strength of the hydrogen bonds that stabilize the $\beta$-sheet structure, $\epsilon$$_{HB}$ ; the strength of van der Waals (vdW) interactions that stabilizes the stacking of the $\beta$-sheet, $\epsilon$$_{vdW}$. Computer simulations of the model found that for $\epsilon$$_{vdW}$/$\epsilon$$_{HB}$ > 0.5, and at low temperature the layers tends to form stacked three-dimensional structures. However, for $\epsilon$$_{vdW}$/$\epsilon$$_{HB}$ < 0.5, the A$\beta$ segments long single-layer $\beta$-sheet similar plaques observed in full length A$\beta$. The implication of the results to AD will be discussed.
        Speaker: Apichart Linhananta (Lakehead University)
      • 4:30 PM
        Exploring conformational switching in proteins with coarse-grained molecular simulations 30m
        The traditional view holds that proteins fold into essentially unique and stable 3-dimensional structures which, in turn, determine their biological functions. Evidence is mounting, however, for a pervasive role of large-scale conformational changes for how proteins carry out their functions. Examples include the ability of some proteins to switch between entirely different folded structures, and the disorder-order transitions exhibited by so-called intrinsically disordered proteins. I will introduce a coarse-grained approach that allows the physics of such conformational switching in proteins to be studied on the computer. The approach is characterized by an intermediate level of geometric detail and a procedure for determining effective model parameters based on the properties of proteins’ global free energy landscapes. I will discuss the implications of our results for the mechanisms underlying molecular recognition and the evolution of new protein folds.
        Speaker: Stefan Wallin (Memorial University of Newfoundland)
      • 5:00 PM
        All-Atoms simulations of Huntingtin’s N-terminal: solvent and membrane effects 15m
        The Huntingtin protein has drawn considerable attention as its aggregation into amyloid fibrils is related to the Huntington disease, a neurodegenerative disease characterized by motor and emotional dysfunctonalities and the loss of cognitive functions. Of its 3000 plus residues, attention has focused mostly on the first exon of Huntingtin, composed of a amphipatic region of 17 amino acids (Htt17), a polyglutamine repeat domain (Q$_N$) and a proline rich domain (C$_{38}$), that modulates its aggregation and localization within the cell. The Htt17 segment is particularly important because it serves as a membrane anchor that could accelerate the fibrilation process. Following recent solution and solid-state NMR experiments that unveiled Htt17’s structure and orientation in micelles and POPC bilayer [1], we refine these experimental finds using a state-of-the-art approach combining molecular dynamics (MD), Hamiltonian replica exchange (HREX) and Metadynamics (MetaD). We focus primarily on the characterization of the dynamics and thermodynamics of Htt17 in solution and in a phospholipid bilayer. In solution, we find that Htt17 samples a broad ensemble of alpha-helix, coil and two-helix bundle structures in agreement with NMR chemical shifts. The addition of the Q$_N$ domain shifts the helical propensity from the amino terminus to the carboxy terminus. Finally, the addition of a polyproline domain stabilizes the helical conformation. Many of the observed structural features could play a crucial role in the aggregation or in the interaction with the membrane [2]. In the phospholipid bilayer, we find that Htt17 could be more structured than the proposed NMR model. Htt17 leads to local deformation of the membrane due to the extension of the neighbor phospholipid acyl chains to cover its nonpolar surface These deformations were shown to promote dimerization of the inserted peptide and could favor the formation of large aggregates [3]. 1. Michalek, M. et al. (2013). Biophysical journal, 105(3), 699-710 2. Côté, S. et al. (2015). Biophysical Journal, 108(5), 1187-1198 3. Binette, V. et al. (2016). Biophysical Journal (In press)
        Speaker: Vincent Binette (Université de Montréal)
    • 3:45 PM 5:15 PM
      M3-7 Atmospheric and Space Physics I (DASP) / Physique atmosphérique et de l'espace I (DPAE) Colonel By D103

      Colonel By D103

      University of Ottawa

      Convener: Shaun Lovejoy (McGill University)
      • 3:45 PM
        The Earth's Hum Comes from the Sun 30m
        It was established over a decade ago that the normal modes of the Earth are continuously excited at times without large earthquakes, but the sources of the ‘seismic hum’ have remained unresolved. In addition to the normal modes of the Earth, we show spectral lines in seismic data with frequencies which correspond closely to normal modes of the Sun. Moreover, the widths of the low-frequency lines in the seismic spectra are similar to those of solar modes and much narrower than those of the Earth’s normal mode peaks. These seismic lines are highly coherent with magnetic fields measured on both the Geostationary Operations Environmental Satellite (GOES)–10 satellite and the Advanced Composition Explorer (ACE) spacecraft located at L1, 1.5 million km sunward of Earth suggesting that the solar modes are transmitted to the Earth by the interplanetary magnetic field and solar wind. The solar modes are split by multiples of a cycle/day and, surprisingly, by the ‘quasi two-day’ mode and other frequencies. Both the phase of the coherences and slight frequency offsets between seismic and geomagnetic data at observatories exclude the possibility that these effects are simply spurious responses of the seismometers to the geomagnetic field. We emphasize data from low-noise seismic observatories: Black Forest (BFO), Pin ̃on Flat (PFO), Eskdalemuir (ESK) and Obninsk (OBN). Horizontal components of seismic velocity show higher coherences with the external (ACE) magnetic field than do the vertical components. This effect appears to be larger near the seismic torsional, or T-mode, frequencies.
        Speaker: Dr Frank Vernon (Scripps Institute of Oceanography, UCSD, La Jolla, California)
      • 4:15 PM
        Advancing Methane Mitigation by Understanding the Physics and Chemical Kinetics of Ultra-lean Combustion Dynamics 15m
        The recent climate change discussions between Canada and the United States of America and other international agreements target methane a potent GHG. The U.S. Environmental Protection Agency will begin developing regulations for methane emissions from existing oil and gas sources while Environment and Climate Change Canada will publish proposed initial phase regulations by early 2017. Although goals are set for anthropogenic methane emissions they should not be the only target for mitigation, thus technology to mitigate naturally occurring methane is required. At present the wetlands emissions, 150–180 TgCH4 per year, are thought to dominate, but the levels of permafrost emissions are potentially much greater. It has been estimated that the methane stored in the permafrost and clathrates may be greater than all other fossil fuels combined and may be poised to be atmospherically released as the Arctic temperature increases. Methane is typically quoted as having about 25 times the forcing factor of carbon dioxide, but that is over a century, it can be more than 84 times that of carbon dioxide over 20 years. The impact is immediate, which may accelerate a positive Arctic feedback loop causing much greater temperatures and rapid release of the stored methane. As reported in Nature, the cost of this methane release could be $60 trillion and the outcome could be disastrous for the climate and world economy. The impetus of this work is on modelling and simulation of ultra-lean methane oxidation/combustion. The challenges associated with ultra-lean methane oxidation are the conditions for ignition of the ultra-lean mixture and sustainability of the combustion process. The interest in MILD combustion has been mainly driven by the need for low emission combustion technology, but methane capture and energy utilisation requires a deeper understanding of ultra-lean combustion. The fundamental studies of the chemical kinetics, physical process and reliable kinetic schemes of ultra-lean methane combustion are sparse, but are required to do proper computational fluid dynamics studies in support of designing and developing advanced mitigation systems. Ultra-lean methane combustion cannot be achieved using traditional combustion technologies because the thermal energy available in the system may not be sufficient to ignite the fuel or even sustain the chemical reactions; thus, the concept of moderate or intense low-oxygen dilution (MILD) combustion is of great relevance. A discussion of the modelling approach in the context of low concentration methane oxidation/combustion is provided. A brief review of anthropogenic emissions of methane and some combustion mitigation and utilisation technologies will be discussed with the view toward developments focused on innovative technologies to achieve sustainable oxidation/combustion and energy capture is discussed.
        Speaker: Dr Daniel Cluff (University of Exeter)
      • 4:30 PM
        The Influence of Turbulence on the Transport of Energetic Particles 15m
        We explore the influence of magnetic turbulence on the transport of energetic particles, mainly cosmic rays, by using test-particle simulations. We compute parallel and perpendicular diffusion coefficients for two-component turbulence, isotropic turbulence, a model based on Goldreich-Sridhar scaling, noisy reduced magneto-hydrodynamic turbulence, and a noisy slab model. We have shown that for all considered turbulence models, the diffusion coefficients are similar. They have the same rigidity dependence and only the absolute values of the diffusion coefficients are different. This conclusion is in agreement with recent analytical findings based on the unified nonlinear transport theory indicating that only fundamental properties of turbulence such as the length scales and magnetic fields control the diffusion coefficients. To double-check the validity and accuracy of our numerical results, we use a second test-particle code. We show that both codes provide very similar results confirming the validity of our conclusions.
        Speaker: Mr Martin Heusen (University of Manitoba)
      • 4:45 PM
        SIMULATIONS OF ENERGETIC PARTICLES INTERACTING WITH DYNAMICAL MAGNETIC TURBULENCE 15m
        We explore the transport of energetic particles in interplanetary space by using test-particle simulations. In previous work such simulations have been performed by using either magneto-static turbulence or undamped propagating plasma waves. In the current work we simulate for the first time particle transport in dynamical turbulence. To do so we employ three models, namely the damping model of dynamical turbulence, the random sweeping model, and the nonlinear anisotropic dynamical turbulence. We also added dissipation effects to the power spectrum, an effect which is usually neglected. We compute parallel and perpendicular diffusion coefficients and compare our numerical findings with solar wind observations. We show that good agreement can be found between simulations and the Palmer consensus range for all dynamical turbulence models if using appropriate values for different parameters in consistent with interplanetary space at 1 AU heliocentric distance. In particular we show that best fit between simulations and observation occurs when the ratio of turbulent magnetic field and mean field is δB/B0 = 0.75.
        Speaker: Mr Martin Heusen (University of Manitoba)
      • 5:00 PM
        A Prototypical Substorm with Conjugate Ground and Space Data 15m
        The substorm at about 5 UT on February 26, 2008 (Angelopoulos et al., Science, 2008) has been taken as prototypical of reconnection in the Near-Earth Neutral Line model. Further examination by Pu et al. (JGR, 2010) showed that the event was preceded an hour earlier by one with very similar signatures. Traditional use of AE-related indices suggests that the first event was smaller in terms of electric currents than the second. More detailed examination of ground magnetic data shows that it was in fact comparable: in addition, the second event was considerably further to the west. The ensemble of data suggests more similarity than differences for the two sub-events. We investigate the potential of inclusion of SCW currents themselves to improve mapping of THEMIS footpoints to Earth poleward of where quasi-static models map, to better match ground and CHAMP observations. Automated Meridian Modeling shows that a simple electrojet model with only three parameters (electrojet borders and current) matches data well with approximately 0.2 MA cross-meridian current in both subevents. GOES spacecraft approximately conjugate to eastern North America show dipolarization signatures consistent with this magnitude of current. There was good conjugacy between hemispheres, as indicated by Antarctic magnetometers and inversion based on them. SuperMag data gives dense enough magnetometer coverage that the layout of the substorm current wedge, with auroral zone westward electrojet and subauroral perturbations mainly due to field-aligned current, can be determined. The quantitative data from the ground provides a context in which flows, magnetic fields, and other parameters at the THEMIS constellation and other conjugate spacecraft may be interpreted.
        Speaker: Martin Connors (Athabasca University)
    • 5:30 PM 7:00 PM
      Welcome BBQ Reception / Réception d'accueil avec BBQ SITE Lawn

      SITE Lawn

      University of Ottawa

    • 7:30 PM 8:30 PM
      Herzberg Memorial Public Lecture - Victoria Kaspi, McGill Univ. / Conférence commémorative publique Herzberg - Victoria Kaspi, Univ. McGill Shaw Centre

      Shaw Centre

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
      • 7:30 PM
        The Cosmic Gift of Neutron Stars 45m
        Although they are thousands of light years away, neutron stars can act as very precise cosmic beacons -- a celestial gift that sheds light on some of the most interesting problems in modern science. We will explore these strange objects, explain how astronomers are using them to study issues ranging from the origins of the Universe to the very nature of matter, and even listen to the cosmic symphony they create.
        Speaker: Victoria Kaspi (Department of Physics, McGill University)
    • 8:30 PM 10:00 PM
      Post-talk Reception Shaw Centre

      Shaw Centre

      University of Ottawa

    • 7:30 AM 8:30 AM
      Science Policy Committee Breakfast Meeting / Réunion-déjeuner du Comité de politique scientifique SITE 5084

      SITE 5084

      University of Ottawa

      Convener: Kristin Poduska (Memorial University of Newfoundland)
    • 8:15 AM 5:15 PM
      Teachers' Day / Journée des enseignants MacDonald 146

      MacDonald 146

      University of Ottawa

    • 8:30 AM 4:15 PM
      Exhibit booths open 08:30-16:15 / Salle d'exposition ouverte de 08h30 à 16h15 SITE Atrium

      SITE Atrium

      University of Ottawa

    • 8:30 AM 10:00 AM
      T1-1 Medical Imaging (DPMB) / Imagerie médicale (DPMB) Colonel By C03

      Colonel By C03

      University of Ottawa

      Convener: Melanie Martin (University of Winnipeg)
      • 8:30 AM
        Magnet and Radiofrequency Technology for Low Cost Magnetic Resonance Imaging 30m
        MRI is a highly effective, but expensive imaging modality. Lower strength magnetic field and lower cost variants of MRI are being developed for specific applications. We will focus on one approach, ‘Transmit Array Spatial Encoding’ (TRASE), which uses only a resonant radiofrequency (RF) field to produce Fourier spatial encoding equivalent to conventional MRI. The usual audio frequency switched magnetic field gradient coils are not needed. We will review different magnet experimental configurations and the MHz RF technology needed to implement these low-cost MRI experiments. High-resolution two-dimensional-encoded in vivo MR images of hand and wrist have been obtained using a uniform 0.2T main magnetic field (B0). An alternative approach is to use an inhomogeneous but very low cost main magnet, in combination with the RF-based image encoding. The mechanism used by TRASE exploits RF field phase gradients to encode image information into echo train NMR pulse sequences. The RF transmit field must be designed to produce these phase gradients, but also must be changed between RF pulses. This can be achieved by multichannel transmitters, or by RF switching, or a combination of approaches. In addition to the low cost advantage, novel experiments exploiting unique capabilities, such as imaging without disturbance of the main B0 magnetic field are possible.
        Speaker: Prof. Jonathan Sharp (University of Alberta)
      • 9:00 AM
        Frequency-Domain Synthetic Aperture Focusing Techniques for Imaging with Single-Element Focused Transducers 15m
        The resolution of conventional single-element ultrasound imaging varies spatially and depends on several factors, such as the central frequency, bandwidth, and the transducer’s active aperture size. Synthetic aperture focusing techniques (SAFT) enable dynamic focusing, which, among others, could lead to improvements in the spatial resolution of ultrasound imaging systems. In SAFT, a large effective aperture is mathematically synthesized by lateral scanning a single-element transducer. Several time-domain SAFT algorithms have been proposed for a single-element focused transducer. In this work, two new frequency-domain SAFT algorithms are proposed, which are based on matched filtering technique and taking into account the diffraction effects of a single-element transducer. The performance of the proposed SAFT algorithms is evaluated for single-element focused transducers with frequencies of 5 MHz, 25 MHz, and 55 MHz. The spatial resolution, signal-to-noise ratio (SNR) and contrast of the proposed frequency-domain SAFT algorithms are compared with conventional B-mode and time-domain SAFT using simulated and experimental data. Preliminary simulation results have shown that the proposed SAFT algorithms yield improved spatial resolution and SNR compared to conventional B-mode and time-domain SAFT. However, the contrasts of the proposed SAFT algorithms are similar to the conventional B-mode and time-domain SAFT.
        Speaker: Mr Elyas Shaswary (Dept. of Physics, Ryerson University)
      • 9:15 AM
        Feasibility of noninvasive temperature estimation using acoustic harmonics 15m
        In this study, the feasibility of obtaining 2D temperature change maps was investigated by estimating the change in backscattered energy of the acoustic harmonics and comparing it with the standard RF echo shift technique. A commercial high-frequency ultrasound scanner (Vevo® 770, Visualsonics Inc., Toronto, ON, Canada) with a 25-MHz center frequency wide-band single-element transducer (RMV-710B, f-number 2.1, 15 mm focal length) was used to transmit signals at 13 MHz. The experiments were performed on gel phantoms composed of 8% (by weight) gelatin. A 1.6 mm thick stainless steel needle was inserted in the gel phantom and hot water was circulated in the needle in order to increase the temperature of the phantom only locally around the needle. Hot water was circulated in the needle by using a peristaltic pump (Masterflex® L/S®, Cole Parmer, Chicago, IL). The needle was not placed within the imaging plane of the transducer in order to minimize the RF signal distortion. The region of imaging was heated from 26°C to 46°C. The experiments were performed with and without a water reservoir and a pulse dampener (Masterflex® L/S®, Cole Parmer, Chicago, IL) in the flow circuit in order to study the effect of motion on both thermometry techniques. The water reservoir and the pulse dampener were used to eliminate vibration in the flow caused by the peristaltic pump. For the proposed method, the backscattered energies of the fundamental frequency (E1), the second (E2) and the third (E3) harmonics were obtained by squaring the envelope of the filtered RF echo signal at each harmonic. The standard echo shift technique was performed by taking cross-correlation between each two frames with a window size of 1×τ (0.07 μs) and an overlap of 50%. In the absence of vibration in the sample, we were able to obtain 2D temperature change maps using both techniques. However, in the presence of vibration, noninvasive thermometry was feasible only by using the backscattered energies of the harmonics.
        Speaker: Mr Elyas Shaswary (Dept. of Physics, Ryerson University)
      • 9:30 AM
        Cholesterol Expels Ibuprofen from the Hydrophobic Lipid Membrane Core 15m
        All drugs must cross the lipid membrane to enter the cell, either by passive or active transport. Diffusing drug molecules may interact with, or embed in, the bilayer and change membrane structure and function. We have observed a significant interaction between cholesterol and the common analgesic, ibuprofen, in model lipid membranes [1]. Using X-ray diffraction in highly oriented, multi-lamellar stacks of lipid membranes, we located the ibuprofen molecule within the bilayer and determined that the drug induces a lamellar to cubic phase transition at concentrations of more than 5 mol%. The phase transition is caused by the presence of ibuprofen in the hydrophobic membrane core, where it induces negative membrane curvature. Cholesterol is a stiff, hydrophobic sterol molecule which also embeds within the membrane core and stiffens lipid tails [2]. When ibuprofen is introduced into membranes prepared with 20 mol% cholesterol, the cubic phase transition is suppressed, as ibuprofen is not able to partition into the core of cholesterol-containing membranes. The results indicate that ibuprofen-membrane interactions strongly depend on membrane composition and properties. The work adds to the growing evidence that amphiphilic molecules, such as aspirin or ibuprofen, significantly disrupt membrane structure [3,4]. [1] **RJ Alsop** *et al*. Soft Matter (2015). 11(24) 4756-4767. [2] MA Barrett, S Zheng, LA Toppozini, **RJ Alsop**, *et al*. Soft Matter (2013). 9(39) 9342-9351. [3] **RJ Alsop** *et al*. Soft Matter (2014). 10(24) 4275-4286. [4] **RJ Alsop** *et al*. BBA-Biomembranes (2015). 1848. 805-812.
        Speaker: Richard Alsop (McMaster University)
      • 9:45 AM
        NEMA Standard Measurements in Pre-clinical PET Imaging 15m

        NEMA (National Electrical Manufacturers Association) Standard Measurements are used for evaluating the performance of the positron emission tomography scanners used in animal imaging. There are various measurements, including spatial resolution, scatter fraction, sensitivity, and image quality.
        In this study the effects of varying the testing procedures of the NEMA NU4-2008 standard for measuring sensitivity and image quality for a small animal PET scanner were examined. In the current NEMA NU4 2008 standard, the sensitivity is measured by stepping a Na-22 point source through the field of view of the scanner along the central Z axis. In some scanners it is not possible to automate the collection of this data, making it very tedious, if not impossible, to acquire the necessary data. As an alternative method, we explore using a long uniform line source extended beyond the field of view in the axial direction and validated this method by comparing our results with those obtained from the standard method. Two line sources were imaged, the first a 70-cm long plastic tube filled with 6 MBq of F-18 (NEMA line source for clinical scanners) and the second a standard 20-cm long Ge-68 sealed line source (0.90 MBq). Point source data were sorted and analysed following the NEMA NU4-2008 method to calculate sensitivity profiles to be plotted as a function of axial distance relative to the center of the field of view. Line source data were analyzed in a manner analogous to the NEMA NU2-2001 method for calculating sensitivity for clinical PET systems. The results from the F-18 and Ge-68 are in good agreement with those from a Na-22 point source (0.93 MBq) using the NEMA standard methods. The difference in absolute sensitivity between Na-22 and the line sources are 0.90% for F-18 and 1.7% for Ge-68 line source. These results represent the equivalence of the sensitivity measurements using a line source or a point source.

        Speaker: Esmat Elhami (University of Winnipeg)
    • 8:30 AM 10:00 AM
      T1-2 Lab Revitalisation: Innovative and Distance Undergraduate Labs (DPE) / Revitalisation de labos : laboratoires de premier cycle innovateurs et à distance (DEP) Colonel By D103

      Colonel By D103

      University of Ottawa

      Convener: Martin Williams (University of Guelph)
      • 8:30 AM
        How redesigning our first-year labs grew into a “Gesamtkunstwerk” in Physics Education 15m
        In this talk, we’ll tell the story of how an initial idea for course redesign grew into something much bigger, incorporating ideas from Physics Education research and the Physics Education community, design of learning spaces, SOTL (scholarship of teaching and learning), building a community of practice etc. along the way – thus “Gesamtkunstwerk”. We will describe how funding for teaching lab renovation and new equipment was combined with turning the lab courses from cookbook style to inquiry-based, including group work with assigned roles, and in-class feedback and assessment. The design team, in consultation with a large number of faculty members, shifted the learning focus towards a more reflective approach to making measurements and analyzing data, and made an introduction to the iterative process of doing science explicit in the course learning goals. This focus allowed much shorter lab instructions, now completely online instead of printed, which required thorough exploration of the technical possibilities of our learning management system, Canvas. We tested our original design in a two-stage process involving faculty, high school/first year students and grad students, using pre-/post-tests, focus groups and observations. We’ll show examples for the labs, results from the two-stage testing (specifically on alignment of the activities and assessment methods with the learning goals) and how they were included in the course design, as well as observations from the first round of implementations. We’ll also point out some spin-off projects, such as the need for an Excel tutorial and restructuring of the teaching materials archive.
        Speaker: Daria Ahrensmeier (Simon Fraser University)
      • 8:45 AM
        Astronomy in the undergraduate advanced laboratory: Studying delta-Scuti variable stars 15m
        Astrophysics concepts acquired in undergraduate courses are sometimes difficult to explore in a teaching laboratory for upper year physics students. We will share our experience developing an experiment on variable stars offered as part of an undergraduate advanced lab courses at Carleton University. The stars studied were mainly of the delta-Scuti type (Dwarf Cepheid), because of their high amplitude variability and fairly short period. With an amateur level telescope and CCD camera, students collect a sequence of variable star images over the period of a few hours, then process and calibrate the images and extract information related to the star. In addition to the technical aspects of data processing in astronomy, students also learn how differential photometry works, investigate the relationship between the period and the luminosity of the star, calculate the distance of the star and, with photometric filters, study its temperature and radius variations.
        Speaker: Etienne Rollin (Carleton University)
      • 9:00 AM
        Introductory Experiments from Scratch 15m
        The Augustana Campus of the University of Alberta will be introducing two major pedagogical initiatives in 2017 that will provide opportunities to reimagine the student experience. One such opportunity will be the creation of an exclusively lab-based, multidisciplinary, compressed-term science course designed for non-science students. I will begin by outlining the context of this new course and its probable features. In particular, I intend to bookend the course with some sort of PER-like testing to investigate the state and evolution of students' attitudes towards science. Next, I'll flip things so that you can provide me with feedback, ideas, or suggestions that might be incorporated into upcoming design phases.
        Speaker: Ian Blokland (University of Alberta)
      • 9:15 AM
        From Particle Physics to Education: The Role of Tinkering 30m
        The love of tinkering is perhaps the single most universal trait among scientists. From designing an experiment to building a computer application to solving a differential equation, the cycle of "observe - explain - test - revise” is at the root of the scientific creative process. Driven by the love of tinkering, we have developed a small low-cost wireless lab system with the goal of putting powerful scientific instrumentation in the hands of every student, both inside and outside of the classroom. I will describe this project and how it is radically changing our view of introductory physics labs at the University of Illinois.
        Speaker: Mats Selen (Universiry of Illinois)
    • 8:30 AM 10:00 AM
      T1-3 Materials Characterization: Electrical, Optical, Magnetic, Thermal (DCMMP) / Caractérisation des matériaux: électrique, optique, magnétique et thermique (DPMCM) Colonel By D207

      Colonel By D207

      University of Ottawa

      Convener: Prof. Eva Hemmer (University of Ottawa)
      • 8:30 AM
        Photon-in Photon-out Spectroscopy of Functional Materials using Synchrotron Radiation 30m
        Using a phosphor to “see” X-rays is as old as the discovery of X-rays and is practiced everyday worldwide. The advent of maturing third generation synchrotron light source technology has made it possible to conduct investigations of X-ray excited optical luminescence (XEOL)from solid in both energy and time domain in much greater details than ever before. In parallel with this development are the advancement of optics and detectors, making it possible to provide energy resolution to an unprecedented level. This together with the brightness of the SR source has made the previously difficult experiments such as high resolution X-ray emission/ resonant inelastic X-ray scattering nearly routine. In this talk, I’ll describe some of these developments and their implications.
        Speaker: Prof. Tsun Sham (Western University)
      • 9:00 AM
        Evolution of electronic structure on transition metal and transition metal doped titanium disulphide by high resolution photoemission spectroscopy study 30m
        In this presentation, I will present the many-body interactions in solids studies by high resolution ARPES. High-resolution angle-resolved photoemission spectroscopy studies of Fe(110) and Ni(110) single crystals has been conducted to clarify the role of many-body interactions acting on the quasi-particles at the Fermi level at low temperatures. We have evaluated the real and imaginary parts of the self-energy for the bulk-derived majority-spin Fermi surface around the Γ point, and found two characteristic energy scales, at ∼40 and ∼270 meV. The former corresponds to the energy scale of the Debye temperature. As for the latter, we found that it is close to the cut-off energy of the calculated magnon density-of-states. This correspondence indicates that the energy scale is related to the magnetic excitation. I will also present our high-resolution photoemission measurements on the transition metal doped dichalcogenides system. TiS$_2$ is proved to be a semiconductor with indirect gas around 600 meV. We confirmed that there is no CDW transition happen. Upon iron atoms intercalation, the strong modification of the valence band structures and the band dispersion in the intercalated com-pound are observed. The hybridization of the S derived states with Fe 3d states is thought to be predominantly the reason. The mechanism of these hybridized bands’ modification has been explained well by Vienna ab initio simulation program and the projected augmented wave poten-tials; the Perdew-Burke-Ernzerhof exchange correlation functional. Finally I will present some of our latest photoemission work in Canadian Light Source Inc.
        Speaker: xiaoyu cui (Canadian Light Source)
      • 9:30 AM
        Enhancing the Luminescence of Silicon Nanoclusters embedded in Silicon Nitride 15m
        In the quest to develop a silicon (Si) based light source, for optical and optoelectronic applications, researchers have explored various techniques. One such technique is the use of self-assembled Si-nanoclusters (Si-NC) embedded in a silicon nitride (Si3Nx) matrix. This system has shown great promise, displaying both photoluminescence and electroluminescence.[1,2] Despite such achievements, the luminescence of Si-NC/Si3Nx devices is still too low in intensity to be used in a commercial light source. An approach that has recently gained interest is the luminescence enhancement of Si-NCs using the localized surface plasmon resonance (LSPR) of metallic nanostructures (m-NS). The majority of research in this area has focused on the use of metals such as gold (Au) and silver (Ag), which are expensive and would increase the cost of any device made using them.[3-6] In our group, we explore how m-NS made using aluminum (Al) can be tailored to enhance the luminescence of Si-NC/Si3Nx devices. Al has the added advantage of being compatible with current manufacturing techniques. To fabricate these m-NS we use nanosphere lithography (NSL). We also examine the mechanisms of luminescence of our Si-NC/Si3Nx devices, to facilitate improvements in luminescence intensity.[7] The results of our work will facilitate the development of commercially viable and cost efficient Si-based light emitting devices. 1. Wang, Y. Q., et al. Applied Physics Letters, 83, 3474 (2003). 2. Cen, Z. H., et al. Journal of Applied Physics, 105, 123101 (2009). 3. Benami, A., et al. AIP Advances, 2, 012193 (2012). 4. Wang, F., et al. Journal of Nanoparticle Research, 15, 1 (2013). 5. Philip, R., et al. Nano Lett, 12, 4661 (2012). 6. Wang, F., et al. Applied Physics Letters, 100, 031113 (2012). 7. Goncharova, L. V., et al. Journal of Applied Physics, 118, 224302 (2015).
        Speaker: Ms Carolyn Cadogan (The University of Western Ontario, Department of Physics and Astronomy)
      • 9:45 AM
        Impurity-based Quantum Circuits in Si 15m
        Recent advances in manipulation of impurities in Silicon by STM techniques, both dangling bonds on Si surface [1] and dopant atoms in Si [2], enable the realization of atomic scale circuits in Si. In this work we focus on phosphorus (P) donors in Si [3]. The 6-fold degenerate conduction band of Si combined with valley-orbit coupling results in a manifold of 6 states of a single P donor. We describe a quantum circuit of P atoms in Silicon with electron population controlled by external gate in analogy to gated quantum dots in GaAs [4]. The electronic properties of these atomic scale quantum dot circuits (QDC), including intra- and inter donor exchange, are described by an extended Hubbard-Kanamori Hamiltonian (HK). The HK parameters show strong dependence on the position of substitutional donors in the Si lattice including on site Coulomb repulsion (U), interdot hopping (t), direct interaction (V) and exchange (J) terms. The interdot, t, V and J, terms strongly depend on dopant position (R_D) in Si lattice—small changes in R_D strongly impact these parameters. We study the influence of QDC design, chains and rings, and how disorder in R_D impacts QDC electronic properties, in particular the interplay of disorder and interactions. With no disorder in R_D the energy spectrum (ES) of quantum dot chain at half-filling as a function of U/t (V,J =0) shows a transition from spectrum dominated by kinetic energy (U/t≪1) to ES dominated by Coulomb interactions for U/t≫1. For weak (strong) interactions the excited states group by single particle energy spacing (Hubbard bands). In the noninteracting regime, disorder leads to electron localization. Using Lanczos and Density Matrix Renormalization Group approaches we explore the effect of interactions and disorder on atomic scale circuits in Si and potential many-body localized phases in the HK model [5]. References [1] M. B. Haider et al. Phys. Rev. Lett. 102 (2009). [2] B. Weber et al. Science 335, 64 (2012). F.A. Zwanenburg et al. Rev. Mod. Phys. 85, 961 (2013). [3] A. L. Saraiva et al, Journal of Physics: Condensed Matter 27, 154208 (2015). [4] C-Y. Hsieh et al, Rep. Prog. Phys. 75, 114501 (2012). [5] D.M. Basko et al. Annals of Physics 321, 1126–1205 (2006). R. Nandkishore and David A. Huse. Annu. Rev. Condens. Matter Phys. 6:15–38 (2015). M. Schreiber et al. Science 21 August 2015: 842-845.
        Speaker: Mr Amintor Dusko do Amaral Oliveira (University of Ottawa)
    • 8:30 AM 10:00 AM
      T1-4 Ground-based and In Situ Observations I (DASP) / Observations sur terre et in situ I (DPAE) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Daniel Cluff (University of Exeter)
      • 8:30 AM
        Transionospheric Radio Propagation Research with CASSIOPE/ePOP 15m
        The Radio Receiver Instrument (RRI) launched in 2013 as part of the Enhanced Polar Outflow Probe (ePOP) payload on the Canadian CASSIOPE small satellite has been successfully operated in a number collaborative transionospheric propagation experiments. The RRI is a digital receiver that operates in the frequency range from 10 Hz to 18 MHz and connects to 4 tubular monopoles usually configured as two orthogonal 6-m dipoles. CASSIOPE's elliptical (325 km - 1500 km) high-inclination (81°) orbit has presented a variety of experimental opportunities in plasma-wave research. Experiments have featured the reception of EM signals from coordinated ground transmitters of various radiated powers in the very-low-frequency to high-frequency range, including VLF communication transmitters, HF ionospheric heaters, HF over-the-horizon radars, HF coherent-backscatter radars, ionosondes and amateur radio sources. In many cases, the distortion of signals in transionospheric propagation observed by the RRI inside the ionosphere may be used to test long-held interpretive assumptions about propagation that normally is only observed when reflected or scattered back to the ground. Special interest arises with radio propagation detected at low altitudes near perigee at 325 km altitude, a height range rarely visited by orbital observatories. The RRI is also used to detect the results of plasma instabilities that occur in different locations in the ionosphere-magnetosphere system and give rise to EM radiation seen on the ground. In many cases, the RRI measurements are part of collaborative studies exploiting other field and particle instruments on the ePOP payload .
        Speaker: Dr Gordon James (University of Calgary)
      • 8:45 AM
        A selection of results from e-POP RRI polarimetry experiments 15m
        Since the outset of science operations with the Enhanced Polar Outflow Probe (e-POP) Radio Receiver Instrument (RRI) in September 2013, over 100 conjunctions with Super Dual Auroral Radar Network (SuperDARN) radars have been completed. With the cross-dipole configuration of RRI's four monopole antennas, and the receiver's high sampling rate, it is possible to determine the polarization state of an individual SuperDARN pulse incident on the receiver. The SuperDARN Saskatoon system transmits a linearly polarized radar pulse which can become separated into packets of elliptically polarized O- and X-mode polarization states as the pulse propagates through to the birefringent ionosphere. Therefore, the full analysis of a SuperDARN pulse may require resolving its O- and X-mode components. We present the results from a selection of e-POP RRI polarimetry experiments with the SuperDARN Saskatoon system, and compare them to past theoretical predictions. The importance of the geometry of an experiment to the resulting polarization measured is discussed.
        Speaker: Dr Gareth Perry (University of Calgary)
      • 9:00 AM
        Initial Results from the AUTUMNX Magnetometer Array 15m
        Most AUTUMNX sites were installed in late 2014, forming a meridian chain along the eastern shore of Hudson Bay. In early 2015, a second, more widely spaced, chain became operational at the longitude of Iqaluit/Kuujauq. These chains provide good coverage in longitude and latitude in eastern Canada, using highly accurate and reliable THEMIS class magnetometers from UCLA. Many substorms have been observed, along with activity characterized as convection bays or steady magnetospheric convection, which may dominate. Isolated impulsive events observed at many stations appear to be related to detectable signals in nearby power grid systems. The meridian chain is conjugate to GOES East and to Antartica, and some events have been observed to have conjugate signatures. The AUTUMNX array was funded by the GO Canada initiative of the Canadian Space Agency.
        Speaker: Martin Connors (Athabasca University)
      • 9:15 AM
        Plasma motion in the equatorial ionospheric F2-layer 15m
        Oyedemi S. Oyekola Etobicoke, ON M8V 3C8 Canada Email: ooyekola@gmail.com Abstract. The structure of evening and nighttime F-region vertical drift component of is vital for understanding the physics of the development of the occurrence of equatorial irregularities. In addition, postsunset ionospheric height has also been attributed as one of the most important factors for the occurrence of equatorial irregularities. We report vertical plasma drift velocities derived from the base (h’F) and the peak height (hmF2) of F-layer using 1-year of data obtained at Ibadan (Geog Long 3.9oE) during International Geophysical Year (1957-58) period for geomagnetic quiet-time and high solar activity conditions. We compared our results with International Reference Ionosphere 2012 model (IRI-2012). The results of this investigation include: (a) overall local- time characteristics of vertical drift between 1800 LT and 0600 LT are in good agreement for equinoxes, December, and June; (b) annual vertical drift derived from time variation of h’F and hmF2 and the corresponding annual variation of h’F and hmF2 variation indicate low correlation (R = 0.30), while IRI-2012 model vertical drift and IRI-2012 model of hmF2 show fairly good correlation ( R = 0.67); (c) regression analysis between time variation of h’F and Scherliess / Fejer model demonstrate correlation coefficient of approximately 0.74 (equinox), 0.85 (December), 0.57 (June) and 0.74 (all-year), while that of time variation of hmF2 and IRI-2012 vertical velocities show 0.95 (equinox), 0.74 (December), 0.43 (June), and 0.74 (all-year); (d) plasma motion derived from the time rate of change of h’F and those of hmF2 are correlated at 0.94, 0.88, 0.63, and 0.90 for equinoxes, December, June, and all-year, respectively; (e) the evening prereversal vertical drifts enhancement rage between ~20 - 45 m/s, ~18 - 46 m/s, ~20 – 50 m/s for time variation of h’F, hmF2, and Scherliess / Fejer model, respectively; (f) the corresponding peak altitudes vary between 430 - 540 km (h’F), 560 – 740 km ( hmF2), and 570 – 620 km (IRI-2012 model).
        Speaker: Dr Oyedemi Oyekola (Private)
      • 9:30 AM
        Swarm Canada: Accomplishments and Opportunities 15m
        Launched in November 2013, European Space Agency's Swarm mission* is now halfway through its nominal science mission. Swarm's on-board experiments, including the Canadian Electric Field Instruments, continue to collect scientific data daily in conjunction with ground-based observatories in Canada and elsewhere. Numerous scientific investigations have been completed or are underway, covering topics from electrodynamics of auroral arcs and pulsations to polar cap patches, Poynting flux, ionospheric structure and thermal balance, and ULF waves. However, only a small fraction of Swarm data have been exploited scientifically, and countless opportunities remain. This talk will summarize the capabilities and potential of the Swarm data with the aim of stimulating new projects and collaborations. Acknowledgement: Canada's participation in Swarm is supported by the Canadian Space Agency and NSERC.
        Speaker: Prof. David Knudsen (University of Calgary)
      • 9:45 AM
        Using Langmuir Probe and faceplate current measurements to validate Swarm Electric Field Instrument bulk ion drifts 15m
        The 3D ion drift measurements from the Electric Field Instruments (EFI) of the European Space Agency’s Swarm mission provide excellent opportunities for multi-satellite and ground-conjunction investigations of ionospheric and auroral physics. Ion drifts are derived from estimates of low-energy (<10 eV) ion energy/angle distributions obtained by Thermal Ion Imagers. In practice, the EFI datasets exhibit sometimes large and often time-varying offsets in the ion drift vector components. Measurements parallel to the satellite velocity vector typically have the greatest uncertainty, with significant contributions from uncertainties in spacecraft-to-plasma potential and ion atomic mass, as well as other sources. Here we present initial findings of an investigation into the feasibility of using simultaneous estimates of ion flux from the EFI Langmuir probes and faceplate current measurements to validate the Swarm along-track ion drifts. Under certain conditions a comparison of TII ion drifts with LP-derived drifts can reveal variations in the mean ion atomic mass in the topside F region ionosphere.
        Speaker: Johnathan Burchill (University of Calgary)
    • 8:30 AM 10:00 AM
      T1-5 Neutrinoless Double Beta Decay II (PPD-DNP-DTP) / Double désintégration beta sans neutrino II (PPD-DPN-DPT) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Thomas Brunner (McGill University)
      • 8:30 AM
        Towards new discoveries with neutrinos and dark matter 30m
        Next generation experiments are poised to help answer fundamental questions about neutrinos and dark matter, but rely on a quantitative understanding of perturbative and nonperturbative QCD. I briefly review the status of experimental searches and theoretical calculations in searchers for lepton number and CP violation in the neutrino sector, and for WIMP dark matter direct detection.
        Speaker: Richard Hill (TRIUMF, Perimeter Institute and University of Chicago)
      • 9:00 AM
        A Scintillator Purification Plant and Fluid Handling System for SNO+ 15m
        A large capacity purification plant and fluid handling system has been constructed for the SNO+ neutrino and double-beta decay experiment, located 6800 feet underground at SNOLAB, Canada. SNO+ is a refurbishment of the original SNO detector to fill the acrylic vessel with liquid scintillator based on Linear Alkylbenzene (LAB) and 2 g/L PPO, and also has a phase to load natural tellurium into the scintillator for a double-beta decay experiment with Te-130. The plant includes processes multi-stage dual-stream distillation, column solvent-solvent extraction, steam stripping, and functionalized silica gel adsorption columns. The plant also includes systems for preparing the scintillator and metal-loading the scintillator for double-beta decay exposure. We review the basis of design, the purification principles, specifications for the plant, and the construction and installations. We also discuss the plant helium leak testing, the passivation and high-purity cleaning, and the plant safety systems. Currently the plant is undergoing testing and commissioning with water, with approvals for LAB commissioning to begin early summer 2016.
        Speaker: Richard Ford (SNOLAB)
      • 9:15 AM
        Commissioning the SNO+ Detector 15m
        SNO+ is a multipurpose neutrino experiment at SNOLAB. Our main physics goal is searching for neutrinoless double beta decay in Tellurium-130. Much work had been done to transform a heavy water detector into a scintillator detector. We are currently commissioning the experiment with water and I will show some early data.
        Speaker: Erica Caden (Laurentian University)
      • 9:30 AM
        Characterization of backgrounds in lucas cells 15m
        For the current generation of experiment on particle astrophysics low backgrounds are very important, which comes with the need for very sensitive measurement tools. A new generation of lucas cells has been produced and this presentation describes the characterization and first steps to simulating the cells performed in the summer 2015. This presentation won first prize at the SNOLAB undergaduate student talk competition.
        Speaker: Elspeth Cudmore (Carleton University)
      • 9:45 AM
        Neutrino-less double beta decay search with Xe-136 and Ba ion tagging R&D 15m
        Neutrino oscillation experiments have shown that neutrinos have finite masses. The study of neutrino-less double beta decay may bring insight on the neutrino mass generation and determine the effective neutrino mass. The next generation neutrino-less double beta decay experiments, with a very large active mass and ultra low background, like the proposed nEXO, will have a sensitivity to the half-life on the order of 10e28 years. These detectors face tremendous challenges for reducing the background due to the trace radioactivity. Standard background reduction techniques have reached a limit and so a novel one must be developed. Double beta decay of Xe-136 produces a Ba-136 ion, the only element for which there is experimentally demonstrated single ion detection and identification capability using resonant light scattering. Tagging the Ba ion can lead to total elimination of the background from radioactive impurities or of cosmic origin. However, applying Ba ion tagging to a massive liquid Xe detector is a challenge. In this talk I will present the field of neutrino-less double beta decay search focusing particularly on Xe-136 as well as the Ba ion tagging efforts within the EXO collaboration.
        Speaker: Prof. Razvan Gornea (Carleton University)
    • 8:30 AM 10:00 AM
      T1-6 Nanostructured and Functional Nanomaterials (DCMMP-DIAP) / Nanomatériaux nanostructurés et fonctionnels (DPMCM-DPIA) Colonel By B205

      Colonel By B205

      University of Ottawa

      Convener: Prof. Adina Luican-Mayer (University of Ottawa)
      • 8:30 AM
        Functional nanostructured surfaces for biomedical applications 30m
        Metals currently used for prosthetic reconstructions (e.g. titanium) enjoy a relatively good success rate, but their performance drops significantly in patients with compromised health status, and post-surgical infections still remain an important challenge. In addition, there are still no such metals that are able to respond to any deterioration of their relationship with the host tissue. To address these needs, different nanotechnology-based strategies have been exploited. Among these, the creation of nanoporous surfaces by simple yet efficient (electro)chemical treatments and the use of polymeric coatings, have emerged as a very effective approach to provide antibacterial properties, drug-delivery capacities and advantageous physicochemical cueing to cells. In this context, we investigated the effects of nanoporous surfaces generated by simple oxidative nanopatterning on the adherence of two common bacteria responsible of implant-associated infections and one yeast strain found in hospital settings. Nanoporous titanium surfaces are also very attractive for their capacity to act as metallic platforms for controlled drug release directly at the implantation site. In this context, we have loaded treated surfaces with Vancomycin, a commonly used antibiotic, and studied the elution profile engendered by the 3-dimensional network of nanosized pits. In order to adapt such technology towards the creation of ‘smart’ materials for in situ ‘gated’ release, we have employed a chitosan-poly(ethylene oxide) (PEG) hydrogel demonstrating a pH-dependent drug release. Such change has been associated with bone remodeling and infections as well as tissue inflammation. Nanoporous surfaces lend themselves to being an effective substrate to immobilize polymeric coatings because of their enhanced surface area and greater amount of binding sites. In this context, we employed a mussel-inspired polymer, poly(dopamine), and carried out extensive investigation of its biological in vitro effects to better understand its direct physicochemical cueing to adhering cells.
        Speaker: Fabio Variola (University of Ottawa)
      • 9:00 AM
        XPCS studies of shear-induced rejuvenation and nano-plasticity in soft glassy materials 15m
        We present x-ray photon correlation spectroscopy experiments on a set of soft glassy solids, including concentrated nanocolloidal gels, nanoemulsions, and Laponite clay suspensions, subject to in-situ oscillatory shear strain that provide insight into particle rearrangements above yielding at the nanometer scale and their connection to dynamical and mechanical behaviour of the materials. The oscillatory strain causes periodic echoes in the x-ray speckle pattern, creating peaks in the intensity autocorrelation function. The peak amplitudes are attenuated above a threshold strain, signalling the onset of irreversible particle rearrangements. These materials generally exhibit macroscopic strain softening (as measured by mechanical rheometry) well below the XPCS peak attenuation threshold, indicating a range of strains at which deformations are nonlinear but reversible. In the gels, the peak amplitudes decay exponentially with the number of shear cycles above the threshold strain, demonstrating that all regions in the sample are equally susceptible to yielding and surprisingly that the probability of a region yielding is independent of previous shear history. However, in the Laponite clay suspensions, which exhibit characteristic mechanical aging behaviour during gelation, attenuation of echoes in he x-ray speckle pattern can be long lived for modest strain amplitudes, a hallmark of mechanical rejuvenation phenomena.
        Speaker: James L. Harden (University of Ottawa)
      • 9:15 AM
        X-ray Speckle Measurements of a Shape Memory Alloy in Training 15m
        The deformation of most types of metals involves an irreversible flow of crystallographic dislocations. This allows for their ductility. The deformation of a metallic shape memory alloy (SMA), on the other hand, is accommodated by a solid-solid phase transition. If deformed in the low-temperature martensitic phase, an SMA can be returned to its original shape by raising its temperature to the point where it changes back to its high-temperature parent phase. When the reverse occurs and the transformation is from parent to martensitic phase, an SMA goes from a high-symmetry to a low-symmetry state in which a number of martensitic variants are produced. Using in situ X-ray Photon Correlation Spectroscopy (XPCS), we monitored the self-organization of martensitic variants in a CuAlNi SMA during thermal cycling. In high-angle scattering geometry, this technique uses correlation from X-ray speckle to quantify the degree of crystallographic change in a material. Our measurements revealed enhanced reversibility in the organization of the martensitic variants as the system became trained during repeated thermal cycling.
        Speaker: Michael Rogers (University of Ottawa)
      • 9:30 AM
        Theory of Nanoscale Friction 30m
        In a nanoscale friction experiment, the tip of an atomic force microscope (AFM) cantilever is dragged along an atomically flat surface, and the resulting friction force is measured optically from the cantilever deformation. Due to the small size of the system, thermal noise effects coming from the atomistic degrees of freedom play an important role. In this talk, the ideas of stochastic modeling will be applied to atomic friction phenomena. We theoretically study atomic friction experiments in the stick-slip regime within the framework of the Prandtl-Thomlinson model. A differential equation describing the force probability distribution is derived. Analytical approximate solutions of this equation are found for the asymptotic cases of high and low effective spring constant, but for arbitrary pulling velocities. Excellent accuracy of these approximate expressions is demonstrated numerically. In particular, the theoretical expression for the mean force, although obtained for small spring constants, is shown to be accurate also somewhat outside of its expected validity range. Finally, the influence of friction aging effect on the experimental friction forces and the ways to include it into the theory are discussed.
        Speaker: Prof. Mykhaylo Evstigneev (Memorial University of Newfoundland)
    • 8:30 AM 10:00 AM
      T1-7 Mass spectrometry in nuclear waste management and control at the border (DIAP-DIMP) / Spectrométrie de masse dans la gestion des déchets nucléaires et surveillance à la frontière (DPIA-DPIM) SITE J0106

      SITE J0106

      University of Ottawa

      Convener: Kirk Michaelian (Natural Resources Canada)
      • 8:30 AM
        Measurement of $^{236}$U in Biota by accelerator mass spectrometry. 15m
        $^{236}$U (half-life 2.34$\times10^7$ y) is a radioisotope of uranium of key importance for tracing the movement of nuclear waste through the environment. Accelerator mass spectrometry (AMS) is the most robust and capable method for measuring $^{236}$U, which has a natural abundance range between 10$^{-8}$ to 10$^{-12}$ or lower. Here we study $^{236}$U uptake in biota samples (plants, animals) and river water samples collected in the region surrounding the Chalk River Nuclear laboratories (Chalk River, ON) by AMS. Plants included the common submerged aquatic waterweeds elodea, myriophyllum and vallisneria. Animals consisted of a variety of freshwater mussle (unionids), an amphipod crustacean (gammarus), a freshwater crustacean resembling small lobsters (crayfish), a small freshwater minnow (spot- tail), a freshwater fish (yellow perch) and a mayfly variety (heptageniids). Samples were ashed, digested, spiked with a $^{233}$U tracer and cleaned through a single-pass UTEVA chemistry in HNO3 followed by U elution in HCl. Post-load UTEVA washes were saved for $^{90}$Sr analysis (Francisco et al [this meeting]). A fraction of the final U eluent was removed for $^{235}$U/$^{238}$U isotopic composition measurements by multi-collector ICP-MS, and the remaining U fraction co-precipitated in iron hydroxide, calcinated, and pressed into AMS targets with an appropriate matrix to optimize uranium emission (Kazi et al [this meeting]). Water samples were processed by direct iron hydroxide co-precipitation of U followed by UTEVA chemistry. We present the AMS analytical testing and results of $^{236}$U partitioning and the $^{235}$U/$^{238}$U isotopic compositions of these biota and water samples.
        Speaker: Christopher Charles (University of Ottawa)
      • 8:45 AM
        Optimization of a methodology to determine 90Sr in biota and water samples by ICP MS QQQ and LSC 15m
        90Sr (t1/2 = 28.80yr) has a relatively long life and due to its chemical similarity to calcium, 90Sr accumulates within the skeletal structure of animals and some plants. The aim of this work is optimize a methodology to determine stable Sr and 90Sr in environmental samples including plants, insects, animals and water. The 88Sr was measured by ICP-MS Triple Quad (8800, Agilent Technologies) and 90Sr by Liquid Scintillation Spectrometer (Quantalus 1220, Perkin Elmer). The Sr was separated from the matrix using the specific Sr EiChrom single resin method (Horwitz 1992). We modified this method to improve the yield and reproducibility of the results. Our optimization focused on adjusting the nitric acid concentration in samples, (8mol L-1) and the use of higher concentrations of hydrochloric acid (6mol L-1) to successfully elute the Sr from the resin. The proposed optimization showed that it is possible to obtain Sr recovery of about 92% if 6 mol L-1 HCl is used as an elution solution. Horwitz, E. P. C. R. D. M. L. (1992). "A Novel Stronium-Selective Extraction Chromatographic Resin." Solvent Extration and Ion Exchange 210(2): 313-336.
        Speaker: Barbara Francisco (University of Ottawa)
      • 9:00 AM
        Contactless Real-time Dynamic Measurements with THz waves and a Rotary Delay Line 15m
        For several years, THz spectroscopy and imaging have been applied to many different fields. However, some burdens still remain in its commercial generalization, particularly for the industry sector. One of these difficulties lies in the acquisition time. In a typical THz time-domain spectroscopy system (THz-TDS), the THz pulse is sampled in time by the means of a micrometer linear delay line. This operation is highly time-consuming, often on the minute scale. We design and fabricate a fast rotary optical delay line (FRODL) consisting of two curvilinear reflectors directly connected to a rotating motor. The optical delay is linear with the rotation angle of the FRODL. The optical input and output are separate and stable to avoid the use of other moving components. We present an experimental implementation of such FRODL. The FRODL surface is made with a CNC machine. We fabricated four blades on the same disk to increase by four the total scan rate. We tested the FRLODL with speeds up to 48 Hz (192 Hz maximum). The total delay was experimentally evaluated to 100 ps. As a first application, we present contactless monitoring of spray painting process and thickness real-time evaluation of the thickness of the paint layer. As a second application, we present the simultaneous detection and thickness characterization of fast moving objects.
        Speaker: Hichem Guerboukha (École Polytechnique de Montréal)
      • 9:15 AM
        Simultaneous Determination of Th and U in Urine by ICP-MS 15m
        ²³²Th is expected to be the major internal dose contributor for nuclear workers in the development of new Th fuels. Since new fuels are usually processed in the same facilities as U fuel is handled, U might also be a significant internal dose contributor. The development of rapid and sensitive analytical methods for the determination of these elements at the levels observed in bioassay samples such as urine is needed. Inductively coupled plasma mass spectrometry (ICP-MS) allows for fast and sensitive detection of these long-lived radionuclides. However, urine contains a significant amount of dissolved salts, organic matter, and suspended particles, which prevent the direct measurement of Th and U by ICP-MS. The traditional purification method for U consists in directly passing an acidified urine sample through an extraction chromatography (EXC) resin; however, this rapid method resulted in inconsistent and poor recoveries for Th. We have demonstrated that the salinity, ligands and suspended particles of urine were hindering the extraction of Th on UTEVA resin without significantly affecting U extraction. A calcium phosphate coprecipitation was first done to remove most of the interferents. Then, the precipitate was dissolved in 8M HNO₃ and the solution oxidized. The solution was passed through a UTEVA resin and the actinides were eluted with 5 mL of a dilute acidic solution. Using this method, a high and consistent recovery was obtained with a low detection limit of 80 and 230 pg•L⁻¹ for ²³²Th and ²³⁸U, respectively.
        Speaker: Mr Alexandre Gagné (Canadian Nuclear Laboratories)
    • 8:30 AM 10:00 AM
      T1-8 General Relaivity (DTP) / Relativité générale (DPT) Colonel By B012

      Colonel By B012

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Gabor Kunstatter (University of Winnipeg)
      • 8:30 AM
        Observation of gravitational waves from a binary black hole merger 30m
        On September 14, 2015, the LIGO detectors observed gravitational waves from a merger of two black holes. This talk describes the LIGO instruments and the LIGO Scientific Collaboration. It presents details of the observed gravitational wave event and discusses implications to astrophysics and tests of general relativity.
        Speaker: Prof. Harald Pfeiffer (CITA, University of Toronto)
      • 9:00 AM
        Universal Horizons in Collapsing Reissner-Nordstrom Metrics 15m
        An investigation of an analogous structure to an event horizon in theories which break Lorentz symmetry. Recent work has shown that in simple spacetimes Lorentz violating theories, such as Einstein-Aether or Horava-Lifshitz, singularities lie behind a *universal horizon* . In the limiting case, signals travel along an incompressible aether which results in an infinitely fast speed of propagation. Despite this property, a universal horizon always appears to form around a singularity disconnecting a region of spacetime from the larger universe. This talk will look at how these structures form during the collapse of a massive charged shell.
        Speaker: Michael Meiers
      • 9:15 AM
        Thermal Mediated Phase Transition in Gauss-Bonnet Gravity 15m
        In this work, we will be introducing so called "thermalons"and studying them in 5 dimentional Gauss-Bonnet Gravity. Thermalons can mediate phase transitions between different vacua in higher curvature gravity, potentially changing the asymptotic structure of the spacetime. Treating the cosmological constant as a dynamical parameter, we study these phase transitions in the context of extended thermodynamic phase space. We find that in the AdS to dS case, thermal AdS can only undergo a phase transition if it is below the Nariai limit. The solutions found beyond Nariai are interpreted as "unphysical". We also find that thermal AdS space can undergo a phase transition to an asymptotically flat black hole geometry. In the context of AdS to AdS transitions, we comment on the similarities and differences between thermalon transitions and the Hawking-Page transition.
        Speaker: Saoussen MBAREK (University of Waterloo)
      • 9:30 AM
        Numerically Obtaining the Black Hole Universality Class 15m
        I will discuss methods to find and extract critical exponents from numerical black holes. This procedure is nontrivial because numerically we compute only the temperature and entropy; assumptions will be made about the complete thermodynamical description via a First Law and Smarr Relation, and tools such as Padé Approximants will be examined. This procedure will be quite general, allowing for utility in scenarios ranging from higher curvature theories to anisotropic solutions.
        Speaker: Wilson Brenna (University of Waterloo)
      • 9:45 AM
        Reentrant phase transitions and van der Waals behaviour for hairy black holes 15m
        The thermodynamics of black holes has remained a subject of interest for more than 40 years. Recently attention has been devoted to the thermodynamics of black holes in extended phase space where the cosmological constant is treated as a thermodynamic variable with the interpretation of pressure. Within this framework, Kubiznak and Mann demonstrated that the charged anti de Sitter black hole is thermodynamically analogous to the van der Waals fluid. A plethora of subsequent work deepened this connection, finding examples of van der Waals behaviour, triple points, and (multiple) reentrant phase transitions for AdS black holes. In my talk I will discuss recent work where we have applied this formalism for the first time to hairy AdS black holes by considering Einstein-Maxwell-AdS gravity conformally coupled to a scalar field in five dimensions. In the absence of electric charge we recover a van der Waals analogy for these black holes for particular configurations of the scalar field. More interesting behaviour is found in the charged case, where both van der Waals behaviour and reentrant phase transitions are seen to occur, the latter due to a modified Bekenstein-Hawking entropy of these black holes. These black holes have an interesting zero-entropy limit at which all critical behaviour ceases.
        Speaker: Robie Hennigar
    • 10:00 AM 10:30 AM
      Health Break (with exhibitors) / Pause santé (avec exposants) SITE Atrium

      SITE Atrium

      University of Ottawa

    • 10:30 AM 11:00 AM
      T-MEDAL CAP Medal Talk - James Fraser, Queen's U. (Teaching Undergraduate Physics / Enseignement de la physique au 1er cycle) Marion 150

      Marion 150

      University of Ottawa

      Convener: Richard MacKenzie (U. Montréal)
      • 10:30 AM
        Going beyond “interactive”: developing scientist-apprentices in the physics lecture hall 30m

        Though an extensive amount of literature documents the improved learning gains made by interactive teaching compared to traditional lecture delivery, results vary widely between courses[1]. Part of the problem is that different instructors aim for active learning through widely varying (and sometimes conflicting) approaches[2]. In addition, even the most well-verified and effective teaching approach will fail without student buy in. I propose a simple framework that can help you identify effective active learning instructional strategies and how to implement them successfully. Results (both positive and less than positive) from a large first-year physics course will be discussed.
        [1] one example among 100s: Freeman et al., Proceedings of the National Academy of Sciences 111, 8410 (2014). For a contrasting view, Andrews et al., CBE-Life Sciences Education 10, 394-405 (2011)
        [2] Turpen and Finkelstein, Physical Review Special Topics-Physics Education Research 5, 020101 (2009)

        Speaker: Prof. James M. Fraser (Queen's University)
    • 11:00 AM 11:30 AM
      NSERC Presentation by Mario Pinto / Présentation du CRSNG par Mario Pinto Marion 150

      Marion 150

      University of Ottawa

      Convener: Adam Sarty (Saint Mary's University)
      • 11:00 AM
        NSERC 2020 Strategic Plan 30m
        I set a number of tasks for myself and for NSERC. Developing and launching NSERC 2020, our strategic plan for the next five years, stood at the top of the list. During a year-long consultation, NSERC benefitted greatly from the input and perspectives of our community through a variety of consultations. I will outline NSERC 2020 in my talk.
        Speaker: Dr Mario Pinto (NSERC)
    • 11:30 AM 11:45 AM
      NSERC EG Chair Report (L.-H. Xu) / Rapport de la présidente du GE (L.-H. Xu) Marion 150

      Marion 150

      University of Ottawa

      Convener: Donna Strickland (University of Waterloo)
    • 11:45 AM 12:00 PM
      CAP-NSERC Liaison Committee Report (W. Whelan) / Rapport du Comité de liaison ACP-CRSNG (W. Whelan) Marion 150

      Marion 150

      University of Ottawa

      Convener: Donna Strickland (University of Waterloo)
    • 12:00 PM 1:00 PM
      DAMOPC Annual Meeting / Assemblée annuelle DPAMC Colonel By B012

      Colonel By B012

      University of Ottawa

      Convener: Matt Reid (University of northern british columbia)
    • 12:00 PM 1:00 PM
      DASP Annual Meeting / Assemblée annuelle DPAE SITE C0136

      SITE C0136

      University of Ottawa

      Convener: Prof. Richard Marchand (University of Alberta)
    • 12:00 PM 1:00 PM
      DNP Annual Meeting / Assemblée annuelle DPN SITE J0106

      SITE J0106

      University of Ottawa

      Convener: Reiner Kruecken (TRIUMF)
    • 12:00 PM 1:00 PM
      DPMB Annual Meeting / Assemblée annuelle DPMB SITE G0103

      SITE G0103

      University of Ottawa

      Convener: Melanie Martin (University of Winnipeg)
    • 12:00 PM 1:00 PM
      DPP Annual Meeting / Assemblée annuelle DPP Colonel By D103

      Colonel By D103

      University of Ottawa

      Convener: Lora Ramunno (University of Ottawa)
    • 12:00 PM 1:00 PM
      IPP Scientific Council Meeting / Réunion du comité scientifique de l'IPP Colonel By E016

      Colonel By E016

      University of Ottawa

      Convener: Michael Roney (University of Victoria)
    • 12:00 PM 1:00 PM
      Lunch / Dîner
    • 12:00 PM 1:15 PM
      NSERC's Research Partnership Programs / Programmes de partenariat de recherche du CRSNG Colonel By D207

      Colonel By D207

      University of Ottawa

      Convener: Bill Whelan (University of Prince Edward Island)
      • 12:00 PM
        NSERC's Research Partnership Programs / Programmes de partenariat de recherche du CRSNG 20m

        This is a moderated panel discussion and Q&A (with NSERC reps, physicists and industry partners) on NSERC funding opportunities available to support researcher-industry partnerships. Learn how to get started, the challenges/rewards and tips for a successful partnership.
        Panelists will be named as they are confirmed.

    • 1:15 PM 2:45 PM
      T2-1 Nuclear Structure II (DNP) / Structure nucléaire II (DPN) Colonel By D103

      Colonel By D103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Prof. Corina Andreoiu (TRIUMF/SFU)
      • 1:15 PM
        Exploring the exotic landscape with direct reactions 30m
        Nuclei far from stability offer us the scope of exploring new features that surface prominently at large isospin and weak binding. This led to the discovery of the nuclear halo bringing a new era in nuclear science breaking the boundaries of conventional concepts. The halo properties elucidate new features that till date remain a challenge to decipher from fundamental principles. Defining the nuclear force from the foundations built on quantum chromodynamics remains one of the major tasks in nuclear physics. The nuclear force is manifested in the characteristics of the nuclei and hence new efforts are underway to couple experiments of the exotic nuclei to ab initio theories. Nuclear reactions are highly sensitive and definitive probes to unravel the unknown new features of the exotic nuclei and hence the nuclear interaction. In this presentation we will introduce a new reaction spectroscopy facility, IRIS, using a novel thin windowless solid hydrogen target. Recent experiments from the facility will be discussed to show observation of halo related excitation modes in the neutron halo nucleus, 11Li. To define the wavefunction of this Borromean halo nucleus, first exploration of its configuration with the unbound 10Li sub-component will be presented. New observations at the proton-drip line exploring the nuclear force will also be discussed.
        Speaker: Prof. Rituparna Kanungo (Saint Mary's University)
      • 1:45 PM
        High-Statistics ${\beta^+/EC}$-Decay Study of $^{122}$Xe 15m
        The Xe isotopes are centrally located in the $Z>50$, $N<82$ region that displays an extraordinarily smooth evolution of simple collective signatures. However, the collectivity of excited states in this region is very poorly characterized because of a general lack of spectroscopic data for low-spin states that provide measures of collective properties such as relative and absolute $B(E2)$ decay strengths and the occurrence of $E0$ decays. There are spectroscopic hints to unusual structures in this region. The $0^+_3$ states in $^{124-132}$Xe are very strongly populated in $(^3He,n)$ reactions, suggesting a pairing vibrational structure influenced by proton subshell gaps, perhaps leading to shape-coexistence that could give rise to strong $E0$ transitions. Recent work on $^{124}$Xe [1] has established nearly identical quadrupole collectivity for the pairing vibrational $0^+_3$ band and the ground state band. However, in $^{122}$Xe, the $0^+_3$ state has not been firmly identified. A high-statistics $^{122}$Cs $\beta^+/EC$ decay experiment to obtain detailed spectroscopic data for low-spin states was performed at the TRIUMF-ISAC facility using the 8$\pi$ $\gamma$-ray spectrometer and its auxiliary detectors including PACES, an array of five Si(Li) detectors, for conversion electrons spectroscopy. The status of the data analysis and preliminary results will be presented. [1] A.J. Radich ${\it et\ al.}$, Phys. Rev. C ${\bf 91}$, 044320 (2015).
        Speaker: Badamsambuu Jigmeddorj (University of Guelph)
      • 2:00 PM
        Doppler-shift lifetime measurements in $^{94}$Sr using the TIGRESS Integrated Plunger 15m
        Neutron-rich Sr isotopes are characterized by a sudden onset of quadrupole deformation at neutron number $N=60$ demonstrated by the dramatic drop in excitation energy of the first $2^+_1$ state. While theoretical calculations reproduce this onset of deformation qualitatively, they differ in the details of the deformation parameters and excitation energies. Though the emphasis is usually put on the sudden onset of collectivity at $N=60$, it is equally surprising that there is no onset of collectivity when adding up to 8 neutrons beyond the $N=50$ shell closure, which points to an amazing robustness of both the $Z=38$ and $Z=40$ proton (sub)-shell closures. This retardation of the onset of collectivity was first observed by Mach et al. [1] measuring extremely low $B(E2)$ values of $\approx 10$ W.u. in even-even Sr isotopes from $^{90}$Sr to $^{96}$Sr using the fast timing technique. These measurements have an uncertainty of $\approx 40\%$ and are at the limit of the fast timing technique with lifetimes of $\approx 10$ ps; a high precision lifetime measurement in $^{94}$Sr will elucidate whether the onset of collectivity is as sudden as generally assumed. Intense re-accelerated beams delivered by the ISAC-II facility at TRIUMF, Canada's national laboratory for particle and nuclear physics, permit access to nuclear structure information for a wide range of radionuclides via in-beam gamma-ray spectroscopy with TIGRESS, a high-efficiency and Compton-suppressed segmented HPGe array. To take advantage of this opportunity, the TIGRESS Integrated Plunger (TIP) has been constructed at Simon Fraser University [2]. The TIP infrastructure supports Doppler-shift lifetime measurements via the Recoil Distance Method (RDM) using a 24-element TIP CsI(Tl) wall for charged-particle identification. An experiment aimed towards a high-precision ($<10\%$) measurement of the $B(E2,2^+_1\rightarrow 0^+_1)$ reduced transition probability in $^{94}$Sr was performed in December 2015 using inelastic scattering near the Coulomb barrier coupled with an RDM lifetime measurement of a radioactive $^{94}$Sr beam. 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. This work is presented on behalf of the TIP and TIGRESS collaborations. [1] Mach et al., Nucl. Phys. A 523 (1991) 197. [2] P. Voss et al., Nucl. Inst. and Meth. A 746 (2014) 87.
        Speaker: Prof. Krzysztof Starosta (Simon Fraser University)
      • 2:15 PM
        Study of 22Ne and 28Mg excited states using fusion-evaporation and Doppler shift measurements 15m
        Electromagnetic transition rate measurements serve as a fundamental probe of nuclear structure and provide a stringent test for theoretical models. Doppler shift lifetime measurements offer an opportunity to directly access information about electromagnetic transition rates and discriminate between model calculations. The TIGRESS Integrated Plunger device (TIP), constructed at SFU, supports Doppler shift lifetime measurements via gamma-ray spectroscopy with the TIGRESS segmented Ge array as part of the experimental program at the ISAC-II facility of TRIUMF. A recent study using TIP employs the fusion-evaporation reaction of 18O + 12C at beam energies of 56 and 48 MeV, with reaction channel selection provided via coincident charged particle detection using ancillary CsI(Tl) detectors. Transitions were identified belonging to the 2 alpha particle and 2 proton evaporation channels from the compound system 30Si, corresponding to 22Ne and 28Mg respectively. Lineshapes, from which lifetimes can be determined by comparison to simulated data, have been observed for these transitions. The experimental approach, analysis procedure, and preliminary comparison of lineshapes to simulations using the GEANT4 toolkit will be discussed.
        Speaker: Jonathan Williams (Simon Fraser University)
      • 2:30 PM
        Investigating the nuclear structure of 33Al through β− decay of 33Mg to probe the island of inversion 15m
        Spectra resulting from the decay reaction of 33Mg were captured using the GRIFFIN γ-ray spectrometer coupled with the SCEPTAR β particle detector at the Canadian laboratory, TRIUMF. A radioactive beam of approximately 104 counts per second of 33Mg was delivered by the Isotope Separator and Accelerator (ISAC) facility. In the past, nuclei away from the valley of stability were experimentally found to have different ground state shell gaps and magic numbers than the ones of those near stability. For example, N=20 is a stable magic number, however the neutron rich 32Mg is known to have a deformed configuration, while 34Si displays a normal configuration. In order to corroborate the theoretical predictions of this inversion mechanism, the nuclear structure of the intermediate 33Al should be known accurately and in detail. A few recent studies have given conflicting results for the branching ratios, spin and parity of the ground state of 33Al. The end goal of this experiment is to determine a fine- grained, conclusive nuclear structure of 33Al through the decay spectroscopy of 33Mg. It is part of a larger experiment using Mg A=34 and 35 isotopes in efforts to map out the island of inversion around N=20. This presentation will focus on the preliminary results from the data processing and analysis done so far, and their significance.
        Speaker: Ms Tammy Zidar (University of Guelph)
    • 1:15 PM 2:45 PM
      T2-2 Nonlinear Dynamics (DPMB) / Dynamiques non linéaires (DPMB) Colonel By C03

      Colonel By C03

      University of Ottawa

      Convener: Melanie Martin (University of Winnipeg)
      • 1:15 PM
        Nonlinear Dynamics for the Translocation of fd Virus through Nanopores: Euler Buckling at the Nanoscale 15m
        The translocation of biopolymers such as DNA through nanopores has received a great deal of attention due to applications such as sequencing DNA or sorting polymers by size. In this presentation I will discuss results from a joint experimental-theoretical project examining the translocation of the filamentous fd virus through nanopores. The fd virus is relatively stiff with a persistence length on the order of its contour length. This is in contrast to typical translocation scenarios where the polymer is many Kuhn lengths in size. Experimental results for fd uncover complex nonlinear dynamics: the translocation speed increases superlinearly with the driving force, the mobility is force-dependent and transitions between scaling regimes with increasing virus length, and the variation in the translocation velocity increases dramatically with increasing driving force. All of these results can be explained by a simple physical picture in which the virus mechanically buckles as it is pushed through the pore and into the fluid on the opposite side of the membrane. This model is explored via Langevin dynamics simulations of the system. Consistent agreement between simulations and experiments verifies the underlying physics thus giving insight into heretofore unexplained experimental results. These findings demonstrate that for the translocation of semi-flexible polymers, the behaviour of the trans portion of the polymer — which is ignored in standard models — has a large impact on the translocation dynamics.
        Speaker: Hendrick de Haan (University of Ontario Institute of Technology)
      • 1:30 PM
        Development of a tapered fiber probe 15m
        Recent advancements in nanotechnology have attracted worldwide attention. The potential applications of metallic nanoparticles, especially gold nanoparticles or nanorods (or gold colloids), are very promising and attractive. The unique optical, chemical, and physical properties of gold nanoparticles make them an ideal candidate for biochemical sensing, medical diagnostics/therapeutics, imaging contrast agents, and photonic devices. The Photonics Research Group at Lakehead University is working towards the development of a photonics device to detect chemicals (e.g., proteins) using Surface-Enhanced Raman Spectroscopy (SERS). We will present the design of a probe using an optical fiber and its application in sensing. The research was financially supported by Natural Sciences and Engineering Research Council of Canada (NSERC) and Agrium Inc.
        Speaker: Mr Joshua Trevisanutto (Lakehead University)
      • 1:45 PM
        Nonlinear dynamics of sensory focussing 30m
        This talk will discuss a non-conventional neural coding task that may apply more broadly to many senses in higher vertebrates. We ask whether and how a non-visual sensory system can focus on an object. We present recent experimental and modeling work that shows how the electric sense can perform such neuronal focussing. This sense is the main one used by weakly electric fish to navigate, locate prey and communicate in the murky waters of their natural habitat. We show that there is a distance at which the Fisher information of a neuron's response to a looming and receding object is maximized, and that this distance corresponds to a behaviourally relevant one chosen by these animals. Strikingly, this maximum occurs at a bifurcation between tonic firing and bursting. We further discuss how the invariance of this distance to signal attributes can arise, a process that first involves power-law spike frequency adaptation. The talk will also highlight the importance of expanding the classic dual neural encoding of contrast using ON and OFF cells in the context of looming and receding stimuli.
        Speaker: Prof. Andre Longtin (Physics, U. Ottawa)
      • 2:15 PM
        Modeling the high frequency electric organ discharge in the weakly electric fish, Eigenmannia 15m
        In the murky waters of the tropics, live weakly electric fish which use a continuous high frequency electric organ discharge (EOD) to sense nearby objects and communicate with conspecifics. Eigenmannia’s characteristic frequency is within the species range of 250 to 600 Hz which it shifts when necessary to avoid jamming. The nearly dipolar oscillating electric field is generated by parallel columns of identical, synchronously discharging electrocyte cells. Recent findings from whole fish respirometry (during high-frequency signaling over a range of frequencies) have renewed interest in the frequency-dependent energetics of the EODs (Lewis et al 2014 J Neurosci 34:197). Although some modeling for that analysis has been performed, many aspects of in vivo electrocyte operation remain unclear, including the role of each compartment of the electrocyte, the amplitude of the oscillatory excursions in voltage, and the optimal way to spread the cost between stimulus and AP generation. In this talk we focus on our model of the neurally-driven electrocyte action potentials (APs) in the innervated posterior membrane that underlie the EOD. Redressing excitability-related Na+ entry constitutes the major ATP-cost for electrocytes and thus for the electric organ. To guide experimental investigation we explored several mechanisms for the generation of the synchronous string of APs. Each scenario has characteristic properties that can be tested experimentally. A highly efficient mechanism involves a tonic subthreshold stimulus mixed with a pulsatile stimulus at the required frequency. This mechanism would reveal a devil’s staircase of responses with steps at periods multiple of the driving frequency and intermediate regions with more complex behavior, if the pulsatile component is insufficient to create a discharge at the required frequency.
        Speaker: Bela Joos (University of Ottawa)
      • 2:30 PM
        The active ear: A ring of fire 15m
        The vertebrate ear both responds to and emits sound. Sounds from the ear, known as otoacoustic emissions (OAEs), provide a means to probe the biophysics of auditory transduction and amplification. Spontaneous emissions (SOAEs) can also be present, appearing as coherent peaks in the spectral domain. Statistical properties of SOAEs, such as the “ring of fire” (observed via a 2-D histogram of the analytic signal of a filtered peak), provide compelling evidence for an "active" ear. Yet the underlying mechanisms are still not well understood. The present study focuses on the lizard ear, a relatively simple case that exhibits robust SOAE. The approach is two-fold. First, we develop a theoretical description that combines active nonlinear oscillators with both local and global coupling. This framework is explored computationally and solved in the time domain. Second, we report recent measurements from lizards that characterize the dynamics of SOAE activity in response to transient external stimuli (e.g., chirps and tone bursts), primarily a depression effect where SOAEs are reduced towards the noise floor. While the model captures some features of the data (e.g., the generation of distinct SOAE spectral peaks) but not others (e.g., SOAE bandwidths and the dynamic range of their response to stimuli), it provides insight into the depression effect. Specifically, SOAEs appear to undergo some combination of entrainment (i.e., synchronization to the external stimulus), suppression (i.e., pushed out of the limit cycle into a quiescent state), or a decoherence (i.e., loss of a clustered group effect that forms a peak).
        Speaker: Christopher Bergevin (York University)
    • 1:15 PM 2:45 PM
      T2-3 Cosmic Frontier: Dark Matter II (PPD) / Frontière cosmique: matière sombre II (PPD) SITE A0150

      SITE A0150

      University of Ottawa

      Convener: Fabrice Retiere (TRIUMF)
      • 1:15 PM
        DEAP-3600 Dark Matter Search with Argon 30m
        The DEAP-3600 experiment will search for dark matter particle interactions on 3.6 tonnes of liquid argon at SNOLAB. The argon is contained in a large ultralow-background acrylic vessel viewed by 255 8-inch photomultiplier tubes. Very good pulse-shape discrimination has been demonstrated for scintillation in argon, and the detector has been designed to allow control of (alpha,n) and external neutron recoils, and surface contamination from 210Pb and radon daughters, allowing an ultimate sensitivity to spin-independent scattering of 10^{-46} cm^{2} per nucleon at 100 GeV mass. The detector is expected to begin collecting low-background data in 2016; the current status of the experiment will be presented.
        Speaker: Prof. Mark Boulay (Carleton University)
      • 1:45 PM
        CDMSlite Run 2 Results 15m
        SuperCDMS searches for dark matter in the form of Weakly Interacting Massive Particles (WIMPs) using germanium detectors operated at a few tens of mK. Particles are detected via the change in resistance of a superconducting transition edge sensor heated by lattice vibrations (phonons) from the interaction. A bias voltage applied across the detector drifts electron-hole pairs produced in an interaction to the electrodes, producing additional phonons (Neganov-Luke effect). The CDMS low ionization threshold experiment (CDMSlite) applies a higher voltage than is normal for these detectors leading to a phonon signal which is strongly dominated by the Neganov-Luke phonons. Through this effect, a much lower energy threshold can be achieved than at lower voltages. Here, we present the results of the second run of CDMSlite which operated at 70 V for 70 kg days and reached a threshold for electron recoils as low of 56 eV. Improvements to the operation of the experiment and the analysis, particularly a fiducial volume cut, allowed for great improvement upon the results from the first CDMSlite run. The fiducial cut is needed because the electric field of this high voltage is distorted at the edges of the detector leading to a reduced Luke amplification at high radius, i.e higher energy backgrounds in this part of the detector fall into the low energy region used for WIMP search.  A radial fiducialization based on a new pulse fitting algorithm was applied to drastically reduce this background. New parameter space for the spin-independent WIMP-nucleon cross section is probed for WIMPs with mass between 1.6 and 5.5 GeV/c$^2$.
        Speaker: Mr Ryan Underwood (Queen's University)
      • 2:00 PM
        Understanding the signal induced within a gaseous spherical detector used by the NEWS experiment 15m
        More than eighty years after its existence was originally postulated, the search for Dark Matter is still ongoing. NEWS is a direct detection experiment that aims to detect WIMPs with a metallic spherical detector with a high voltage electrode in its centre, with gas as its target mass. In the context of the NEWS experiment, our estimators of the energy of events, and their position within the detector, are based on the amplitude and risetime of our signal. We have developed an in-depth understanding of the formation process of our signal, specifically the response function of our physical detector and its electronics. Through a digital deconvolution of this response function, we recover the original electronic signal released by an energy deposition in the target volume. This allows for optimum discrimination between nuclear recoils and other pulses, and improved estimators of the energy and position of events.
        Speaker: Francisco Andres Vazquez de Sola (Queen's University)
      • 2:15 PM
        The PICO 0.1 bubble chamber calibration 15m
        The search for dark matter calls for increasingly sensitive experiments. For several decades now, scientists have built more and more sensitive detectors in the hope to directly detect WIMPs, a type of candidate particles for dark matter. WIMPs should interact with normal matter by elastic scattering with nuclei. Experiments are typically performed underground to shield them from cosmic and atmospheric radiation. However, an important background radiation for dark matter experiments is neutrons present underground, whose response in detectors is indistinguishable form that of a WIMP. The full understanding of the neutrons’ response in dark matter detectors is, therefore, of the utmost importance. The PICO collaboration presently operates two bubble chambers in the SNOLAB underground laboratory in Sudbury, Ontario. An effort is being made by the collaboration towards the understanding of those chambers’ behavior. To this aim, multiple calibration chambers have been built. The PICO 0.1 chamber is operated at the Tandem Van de Graaff facility of the Université de Montréal where a proton beam is used to produce mono-energetic neutrons from the $^{51}V(p,n)^{51}Cr$ reaction. This chamber has shown to be one of the cleanest and most reliable chamber designed by the collaboration, which makes it the perfect detector to perform the neutron calibration. This talk will explain the goal and experimental method of the measurements. Preliminary results of the calibration will also be presented.
        Speaker: Mr Frédéric Girard (Laurentian University)
      • 2:30 PM
        **WITHDRAWN** Characterization and mitigation of particulate sources of backgrounds in the PICO-60 experiment 15m
        The PICO experiment is a dark matter search using superheated liquid C$_3$F$_8$. The experiment operates two bubble chambers, PICO-2L and PICO-60, at the SNOLAB facility 2km underground, and is designed to be most sensitive to spin-carrying dark matter particles with a mass range of 10-10,000 GeV/$c^2$. PICO bubble chambers are threshold detectors that can be operated within a set of conditions where they are insensitive to minimally ionizing particles. Acoustic, pressure and video information is used to discriminate between nuclear recoil events and background alpha events. PICO-60 is presently being upgraded to perform dark matter searches with 60 kg of active liquid at a threshold energy of 3.2 keV. A large fraction of the background events in the previous run of PICO-60 with CF$_3$I exhibited behaviours consistent with particulates in the active volume. In this talk, an overview of the particulate contamination and background events with a possible particulate origin will be presented. The procedure developed to identify the particulates and to characterize them and their sources will be discussed, along with assay results from previous run. Strategies for mitigation of the generation mechanism and modifications to the detector to eliminate the particulate load on the detector in the next run are also presented.
        Speaker: Pitam Mitra (University of Alberta)
    • 1:15 PM 2:45 PM
      T2-4 Ground-based and In Situ Observations II (DASP) / Observations sur terre et in situ II (DPAE) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Martin Connors (Athabasca University)
      • 1:15 PM
        Studying the Lower Thermosphere with Alberta’s First Cube Satellite: Ex-Alta 1 30m
        Ex-Alta 1 is the pioneer cube satellite for the AlbertaSat team at the University of Alberta and will be the first built-in-Alberta satellite. This 3U cube satellite is designed and assembled primarily by volunteer undergraduate students at the U of A, with guidance from several researchers and faculty members. In this way, AlbertaSat offers a unique opportunity to train highly qualified personnel for eventual careers in aerospace. Ex-Alta 1 is one of two Canadian satellites participating in the QB50 mission coordinated by the Von Karman Institute in Brussels, Belgium. It will be deployed from the International Space Station in the autumn of 2016. Thus, its initial orbit will be at an altitude of 400 km and inclination of 52°. Once in orbit, Ex-Alta 1 will study space weather, using a range of scientific instruments, and will act as a qualification opportunity for the first model of a new suite of open source cube satellite subsystems being developed at the University of Alberta. Ex-Alta 1 is equipped with three scientific payloads. The multi-Needle Langmuir Probe (mNLP) experiment, developed at the University of Oslo, will study variations in ion densities. These measurements can be used to better quantify how the Earth’s atmosphere expands and contracts into low Earth orbit. The mNLP will also enable the collection of information to study the effects of re-entry. A Digital Fluxgate Magnetometer (DFGM) developed and built at the U of A will be deployed at the end of a 60 cm boom and will study the Earth’s magnetic field in low Earth orbit. Finally, a radiation dosimeter onboard Ex-Alta 1 will measure variation in radiation levels in low Earth orbit, thus giving insight into average electron and proton flux during the mission. Data generated by Ex-Alta 1 will be curated by teams at the University of Alberta and the Von Karman institute and made available to the scientific community. Ex-Alta 1 will also include the Athena on-board computer. This on-board computer for cube satellites is a fully open source system designed and built by senior undergraduate students at the University of Alberta. It will be tested and qualified on the Ex-Alta 1 mission, and will then form the foundation for future cube satellite projects carried out by the AlbertaSat team.
        Speaker: Mr Charles D. A. Nokes (University of Alberta)
      • 1:45 PM
        Statistical investigation of anisotropic ion temperature enhancements observed by the CASSIOPE/e-POP satellite 15m
        Terrestrial ion outflow and loss to space is the result of acceleration to escape speed of ionospheric ions that normally are strongly bound to earth through gravity. Previous research suggests this acceleration takes place in multiple steps. We investigate low-energy (<10 eV) ion initial energization processes in the topside ionosphere in both hemispheres using data from the SEI, MGF and RRI instruments onboard the CASSIOPE/e-POP satellite. Using the high-frame-rate (100 Hz) two-dimensional ion distribution function data measured by the SEI, we statistically investigate anisotropic ion temperature enhancements, where ion temperatures perpendicular to B rise by more than 0.4 eV relative to the background values while temperatures parallel to B decrease, and study their morphology and Kp dependence. Multiple field-aligned current (FAC) sheets are found to be always associated with these events based on magnetic data from the MGF instrument. For some events, signatures of broad-band extremely low frequency (BBELF) plasma waves, auroral hiss and chorus are detected by the RRI instrument. We study the causal relations between the anisotropic ion temperature increases and the magnitudes of the FACs and the power spectral density (PSD) of plasma waves.
        Speaker: Yangyang Shen (University of Calgary)
      • 2:00 PM
        Field-aligned currents associated with multiple arc systems 15m
        The field-aligned current (FAC) system associated with auroral arcs provides important information regarding the generator responsible for multiple arc systems, and presumably for individual arcs themselves. We have identified two types of FAC configurations in multiple parallel arc systems using ground-based optical data from the Themis all-sky imagers (ASIs), and magnetometers onboard the Swarm satellites during the period from December 2013 to March 2015. The first type represents a collection of multiple up/down current pairs and the other is an arc system within a broad unipolar upward current sheet. We find that (1) events corresponding to the first FAC type are mainly located in the 23-0 MLT sector, and the second type between 20-22 MLT. (2) The average current intensities for upward and downward currents in the first type are similar (~0.16 A/m). However, for the second type, the upward average current intensity (~0.32 A/m) is greater than the downward current (~0.21 A/m). (3) the average current density is larger in the first type for both upward and downward currents, with the latter, however, having a larger average density than the former in both types. (4) upward currents with more arcs embedded have a larger intensity, although the intensity of upward currents and the number of arcs do not show a linear relationship.
        Speaker: Jiashu Wu (University of Calgary)
      • 2:15 PM
        Monitoring HF transmissions with the e-POP RRI instrument on the CASSIOPE Satellite 15m
        The Radio Receiving Instrument (RRI) on e-POP payload of the CASSIOPE satellite has a relatively high sampling rate and orthogonal dipole antennas which permit the observation of continuous wave (CW), pulse and phase coded signals from transmitters on the earth. In this study, high frequency (HF) 13-bit Barker-coded binary phase shifting keying (BPSK) and CW signals are detected from a transmitter in Ottawa during satellite overpasses. The HF signal experiences several of physical effects such as ionospheric delay, Faraday rotation, Doppler shifting and mode splitting during propagation through the ionosphere. Using the BPSK pulses (of 15 msec repetition rate), independent Doppler shift estimates can be rapidly determined using amplitude and phase characteristics of the waves. During the CW transmissions, amplitude variations on the orthogonal dipoles highlight the nature of the wave propagation through the ionosphere in the HF band.
        Speaker: Donald Danskin (Natural Resources Canada)
      • 2:30 PM
        Using the motion of Pulsating Aurora Patches to investigate the change in magnetospheric convection 15m
        Magnetospheric convection, the main process of the acceleration and injection of energetic particles into the magnetosphere, plays an important role in the study of Earth’s magnetosphere. One of our previous studies has compared the motion of Patchy Pulsating Aurora (PPA) patches with the corresponding ionospheric convection inferred from the SuperDARN radar measurements. The result shows that the motion of the PPA patches follows the convection and suggests that the motion of PPA patches could be a great new tool to remote sense the magnetospheric convection with high temporal and spatial resolution. We later have compared the patch velocities with the corresponding magnetospheric convection velocities inferred from the electric field measurements from RBSP. Although the result shows a great consistency between these two velocities, with small values of electric field measurements there might be a great uncertainty introduced into the derivation of convection velocities. In this study, we look into the PPA events with changing velocities and compare their variations with the changes of the corresponding electric field measurements from RBSP. The result not only can show us whether the motion of PPA patches follows the magnetospheric convection but also suggest the variation in convection is due to the change in large-scale or small-scale electric field.
        Speaker: Bing Yang (University of Calgary)
    • 1:15 PM 2:45 PM
      T2-5 Photonics I: Applications (DAMOPC-DPP) / Photonique I : applications (DPAMPC-DPP) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Paul Barclay (University of Calgary)
      • 1:15 PM
        Generation of nonclassical states of light using photonic crystal fibers 30m
        Photonic crystal fibers (PCF) offer unique control of dispersion and nonlinearity and have revolutionized nonlinear optics. We present the possibility to use hollow-core and solid-core PCF for the generation of bright twin beams and photon triplet states. One advantage to use optical fibers is that both signal and idler can be generated in a single spatial mode. By pumping close to the zero dispersion wavelength of the fiber, such sidebands can be created through modulation instability. However, signal and idler appear in the vicinity of the pump and Raman-scattering originated from the pump deteriorates the photon correlation by increasing the background level of photons of the idler. Here we use kagomé-lattice hollow-core PCF filled with argon to generate ultrafast bright twin beams [M.A. Finger *et al*. PRL. **115**, 143602 (2015)]. Since a monatomic gas provides the nonlinearity the source does not suffer from Raman-scattering and sidebands close to the pump are generated. We measure ~35% twin beam squeezing below shot noise. Another unique advantage of this source is the tunability of the sidebands through the gas-filling pressure. Next, we address the challenging problem of generation of triplet states through spontaneous decay of one pump photon propagating in a $\chi^{(3)}$-material. This process is the reverse of third harmonic generation and phase-matching conditions are identical. Due to chromatic dispersion phase-matching cannot occur between two identical modes and this implies for the generation of triplet that the pump light has to be launched in a higher-order mode, leading to a reduced generation efficiency due to mode-mismatch between pump and triplets. Here we propose a hybrid solid-core PCF to circumvent this difficulty. The short-wavelength (~532 nm) is guided in a single-lobe mode by an all-solid photonic bandgap (PBG) while the guidance of the long-wavelengths relies on step-index. The inner PBG consists of a hexagonal array of high-refractive index glass (Schott SF6, n=1.81) embedded in a lower index host (Schott LLF1, n=1.55). The overall dispersion is strongly affected by these two distinct mechanisms and we demonstrated phase-matched third harmonic from fundamental mode at 1521 nm into the “fundamental” bandgap-guided mode ($\lambda$=507 nm), for which the field distribution is very similar to that of the LP01 mode of a step-index but with narrower mode-field diameter [A. Cavanna *et al*., in preparation].
        Speaker: Prof. Nicolas Joly (Max-Planck Institute for the Science of Light)
      • 1:45 PM
        Integrated silicon photonics for quantum communication 30m
        The surging progress in silicon photonics over the past decade has been driven by its potential deployment in low cost, high bandwidth, wavelength-division multiplexed short reach optical interconnections in datacenters. Many device level advances have been made in recent years, and the variety of high quality components that have become available now motivate extending the application of silicon photonic integrated circuits to quantum information. In this talk, I will present my group’s recent work on silicon photonics for quantum communication. I will describe high extinction ratio microring modulators and filters, the first polarization rotator-splitters and controllers in standard silicon photonic platforms, and a prototype of an integrated quantum key distribution transmitter for the BB84 protocol.
        Speaker: Joyce Poon (University of Toronto)
      • 2:15 PM
        Optical decoherence and spectral diffusion in an erbium-doped silica glass fiber featuring long-lived spin sublevels 15m
        Rare-earth-ion (REI) doped materials offer unique spectroscopic properties, such as narrow optical linewidths, or long-lived shelving levels that allow for spectral tailoring of their inhomogeneously broadened absorption lines. Indeed, both these properties are required simultaneously in order to implement many of the potential applications of (REI) doped materials, such as optical quantum memories. REI-doped glasses come with some advantages compared to REI-doped crystal hosts such as a larger inhomogeneous broadening, benefitting large-bandwidth applications, but also disadvantages such as coherence times limited by two level systems. Here, we study the coherence properties of a weakly doped erbium silica glass fiber, motivated by our recent observation of efficient and long-lived Zeeman level storage in this material and due to its potential for applications at telecommunication wavelengths. We present a model describing the magnetic field and temperature dependence of the coherence lifetime and determine the processes limiting the latter in different regimes. Furthermore, we investigate spectral diffusion, and find that it is magnetic field independent over long time scales. We highlight the observation of effective linewidths of the order of 1 MHz at low magnetic fields, where efficient spectral tailoring is possible.
        Speaker: Mr Mohsen Falamarzi Askarani (Department of Physics and Astronomy, University of Calgary)
      • 2:30 PM
        Hollow-core photonic Bragg fiber for bulk and surface sensing applications 15m
        We demonstrate a hollow-core photonic Bragg fiber for bulk and surface sensing applications. The sensor operates on a resonant sensing modality. Variation in the fiber core effective refractive index modifies the bandgap guidance of the fiber, leading to a spectral shift in the fiber transmission spectrum. As a demonstration for the bulk sensing application, we apply the fiber sensor to detect refractive index of analyte filling in the fiber core, a sensitivity of 1500nm/RIU is achieved. As a demonstration for the surface sensing application, we use it to monitor the dissolution dynamic of a thin film coated on the fiber core inner surface, the obtained surface sensitivity is found to be 0.05nm/nm. The proposed sensor presents a ‘one fiber’ solution for both bulk and surface sensing applications, which is promising for the development of a new generation of the fiber-based biosensors.
        Speaker: Jingwen Li (polytechnique de montreal)
    • 1:15 PM 2:45 PM
      T2-6 Condensed Matter Theory (DTP-DCMMP) / Théorie de la matière condensée (DPT-DPMCM) Colonel By D207

      Colonel By D207

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Prof. Pawel Hawrylak (University of Ottawa)
      • 1:15 PM
        Investigations of the Intermolecular Interactions between Organic Conjugated Monomers, and Conjugated Oligomers and Nanotubes Using Dispersion-Corrected DFT 30m
        This talk will focus on discussing and analyzing intermolecular interactions between organic conjugated polymers used in organic light-emitting diodes (OLEDs) and between conjugated oligomers and carbon nanotubes (CNTs) in CNT-oligomer composites. Dispersion-corrected density functional theory will be employed to study these systems. The construction of multilayered OLEDs typically involves extensive experimental searches for the combinations of polymers that give the optimum device performance. As an example, combinations of different fluorene-based conjugated polymers such as alternating triphenylamine-fluorene (TPAF)- and oxadiazole-fluorene (OxF)-based conjugated copolymers were considered as components of multilayered OLEDs. It was found that certain combination gave the best OLED performance. Our results illustrate that the best combination of polymers has monomers that have the closest intermolecular distance and the highest binding energy relative to all the other combinations. Pure CNT and CNT-oligomer/polymer composites have many useful (industry related) properties: ranging from electrical conductivity to superior strength. However the full potential of using CNTs as reinforcements (in say a polymer matrix) 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 identify the type of conjugated oligomers that are best suited for the dispersion of single walled CNT (SWCNT). We investigate the effect of intermolecular interactions on the structure, polarity and energetics of the oligomers in presence of SWCNT.
        Speaker: Jolanta Lagowski (Memorial University of Newfoundland)
      • 1:45 PM
        The phase diagram of the Blume-Capel-Haldane-Ising spin chain 15m
        We consider the one-dimensional spin chain for arbitrary spin s on a periodic chain with N sites, H = \sum_i^N ( a (S_i^z)^2 + b S_i^z S_{i+1}^z ), the generalization of the chain that was studied by Blume and Capel. The Hamiltonian only involves the z component of the spin thus it is essentially an Ising model. The Hamiltonian also figures exactly as the anisotropic term in the famous model studied by Haldane of the large spin Heisenberg spin chain. Therefore we call the model the Blume-Capel-Haldane-Ising model. Although the Hamiltonian is trivially diagonal, it is actually not always obvious which eigenstate is the ground state. In this presentation we establish which state is the ground state for all regions of the parameter space and thus determine the phase diagram of the model. We observe the existence of massless soliton-like excitations and we show that the size of the solitons depends only on the ratio a/b and not on the number of sites N.
        Speaker: Christian Boudreault (Collège militaire royal de Saint-Jean / Université de Montréal)
      • 2:00 PM
        The motion of spherical particles in a simple ratcheting system with AC Fields 15m
        Hanyang Wang, Gary W. Slater University of Ottawa Ratcheting systems make it possible to control the motion of particles in such a way that it becomes possible to separate mixtures of particles on the basis of various physical properties (such as charge, size, shape, etc.). The ratcheting system that we study is a standard microfluidic channel with symmetry breaking obstacles placed periodically. Zero-mean alternating electric fields are found to lead to a net ratcheting motion of the particles, whether the field is applied along the channel's axis or perpendicular to it. The resulting particle velocities depend on the particle's size and charge, thus permitting separation. We show that it is possible to make particles move in opposite directions even though their charge is of the same sign. We then explore the possibility of using rotating electric fields, with and without channel walls. In the absence of walls, i.e. with a two-dimensional distribution of obstacles, we show that it is possible to make different particles move along different directions in the plane.
        Speaker: Hanyang Wang (University of Ottawa)
      • 2:15 PM
        Long-term behaviour of granular chains held between walls is really equilibrium. 15m
        Granular chains have been the focus of a number of studies, in part due to their numerous applications, ranging from shock absorption and vibration reduction to energy localization. Force impulses to an unloaded granular chain result in a propagating solitary wave (SW), analogous to a soliton of the Korteweg-de Vries equation. When SWs collide with a boundary or another SW, secondary solitary waves (SSWs) are produced as grains break contact. A consequence of this process is the transition from a non-ergodic, SW dominant, phase to the stable "quasi-equilibrium" (QEQ) phase, thought to be distinct from true thermodynamic equilibrium due to the absence of equipartitioning of energy. We show that, in the absence of energy dissipation, when granular systems are allowed to evolve to extremely long times, the number of SSWs becomes sufficiently large that the system actually approaches a true equilibrium phase. In this extreme-time limit, energy in fact becomes equipartitioned among all grains, and we illustrate how the specific heat and kinetic energy fluctuations can be predicted by the generalized equipartition theorem, regardless of the degree of the interaction potential. This opens up the possibility that granular systems should be treated by equilibrium statistical mechanics.
        Speaker: Michelle Przedborski (Brock University)
      • 2:30 PM
        Critical noise parameters for fault tolerant quantum computation 15m
        Noise is imminent to a quantum computing process. With the help of quantum error correcting codes, the logical information in a qubit can be preserved by encoding it in a system of several physical qubits and by performing gates in a fault tolerant manner. However, it is crucial to know the noise model affecting the physical qubits, in order to estimate the error on the logical qubit and thereby the overhead required for fault tolerant quantum computation. For some specific types of quantum channels it is easy to identify a parameter of the physical channel that controls the logical error rate. However, for a realistic noise model, it is unclear which of the physical parameters are critical to the logical error rate. In this work, we aim to determine the parameters of a single qubit channel that can tightly bound the logical error rate of the concatenated Steane code. We do not assume any a priori structure for the physical quantum channel, except that it is a completely positive trace preserving (CPTP) map. Our method of estimating the logical error rate differs significantly from the standard and computationally expensive Monte-Carlo sampling of the error distribution. We employ a technique to compute the complete effect of a physical CPTP map, at the logical level, with just one round of error correction. By such numerical simulations on random quantum channels, we have studied the predictive power of several physical noise metrics on the logical error rate, and show that, on their own, none of the natural physical metrics lead to accurate predictions about the logical error rate. We then show how machine learning techniques help us to explore which features of a random quantum channel are important in predicting its effect at the logical level.
        Speaker: Mr Pavithran Iyer (Université de Sherbrooke)
    • 1:15 PM 2:45 PM
      T2-7 Gravity, Astrophysics and Cosmology (DTP) / Gravité, astrophysique et cosmologie (DPT) Colonel By B012

      Colonel By B012

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Svetlana Barkanova (Acadia University)
      • 1:15 PM
        New exact solutions to the Einstein field equations 30m
        We present new classes of exact solutions to the five dimensional Einstein gravity with cosmological constant, coupled to the Maxwell and dilation fields. The theory has two coupling constants for dilation-Maxwell and dilation-cosmological constant terms. The solutions are non-stationary and moreover almost regular everywhere for non-zero coupling constants. The cosmological constant depends on the dilation coupling constant and can take positive, zero or negative values.
        Speaker: Masoud Ghezelbash (University of Saskatchewan)
      • 1:45 PM
        Generating Einstein gravity, cosmological constant and Higgs mass from restricted Weyl invariance 15m
        Recently, it has been pointed out that dimensionless actions in four dimensional curved spacetime possess a symmetry which goes beyond scale invariance but is smaller than full Weyl invariance. This symmetry was dubbed *restricted Weyl invariance*. We show that starting with a restricted Weyl invariant action that includes pure $R^2$ gravity and a Higgs sector with no explicit mass, one can generate the Einstein-Hilbert action with cosmological constant and a Higgs mass. The model also contains an extra massless scalar field which couples to the Higgs field (and gravity). If the coupling of this extra scalar field to the Higgs field is negligibly small, this fixes the coefficient of the nonminimal coupling $R \Phi^2$ between the Higgs field and gravity.
        Speaker: Prof. Ariel Edery (Bishop's University)
      • 2:00 PM
        Relativistic Geoids 15m
        In non-relativistic physics a geoid is a surface of constant gravitational potential. Here I propose, in the context of general relativity, the notion of a geoid -- a surface of constant "gravitational potential". This idea emerges as a specific choice of a previously proposed, more general and operationally useful construction called a quasilocal frame -- that is, a choice of a two-parameter family of timelike worldlines comprising the worldtube boundary of the history of a finite spatial volume. I describe the geometric properties of these geoid quasilocal frames, and construct solutions for them in some simple spacetimes. These results are then compared to their counterparts in Newtonian gravity and compute general relativistic corrections to some measurable geometric quantities. This work may have applications in applied geodesy.
        Speaker: Robert Mann (University of Waterloo)
      • 2:15 PM
        A generalized model of repeated quantum interactions 15m
        We study the different scenarios that repeated quantum interactions between a system S and an ancillary system Sm induces on the former. These latter systems play the role of measurement devices, or meters. Distinct dynamics emerge depending on various limits that can be taken for the ancillae. Of special interest is the case where induced effective interactions between subsystems of a composite system arise due to their repeated interactions with a common set of meters, which we use to investigate the possibility of describing gravity as a classical channel, or in other words, that gravity arises as an effective force that cannot transmit quantum information.
        Speaker: Paulina Corona Ugalde (University of Waterloo)
      • 2:30 PM
        Tunneling decay of false vortices: Gravitational effects 15m
        We consider the decay of vortices trapped in a $U(1)$-breaking false vacuum of a Einstein-Hilbert-Higgs theory in $2 + 1$ dimensions. In the true vacuum, the $U(1)$ symmetry is unbroken. The potential of the model allows the formation of metastable vortex solutions. These vortices contain the true vacuum inside in addition to a unit of magnetic flux and the appropriate topologically nontrivial false vacuum outside. The work presented extends a previous analysis by coupling the vortices to gravity. We employ numerical methods as well as analytic methods using the so-called thin-wall approximation to verify that static metastable vortices remain when gravity is turned on. In the latter case, knowledge of the metric of space-time inside and outside the core of the vortex allows one to use Israel's junction conditions and to study the dynamics of the vortex's radius. We compute an estimate for the tunneling amplitude of the vortex in the semiclassical approximation. This process of tunneling through expansion of a vortex core is of cosmological importance, as it could be much more rapid than the spontaneous decay of the false vacuum.
        Speaker: Éric Dupuis (Université de Montréal)
    • 1:15 PM 2:45 PM
      T2-8 Doing Physics-doing Gender: Should gender issues be of any importance in the physics community? (CEWIP) / Physique et genre : les questions de genre devraient-elles avoir de l'importance dans la communauté de physique? (CEFEP) SITE J0106

      SITE J0106

      University of Ottawa

      Convener: Shohini Ghose (Wilfrid Laurier University)
      • 1:15 PM
        Is “interactive” teaching sufficient to promote conceptual development in physics? 30m

        Over the past few decades, systematic research has shown that many physics students express essentially the same (incorrect) ideas both before and after instruction. It is frequently assumed that these ideas can be identified by research and then addressed through “interactive” teaching approaches such as hands-on activities and small-group collaborative work. In many classrooms, incorrect ideas are elicited, their inadequacy is exposed, and students are guided in reconciling their prior knowledge with the formal concepts of the discipline. Variations of this strategy have proven fruitful in science instruction at all levels from elementary through graduate school. However, this summary greatly over-simplifies the use of students’ ideas as the basis for effective instructional strategies. Examining what students have actually learned after using research-based curriculum is essential for improving the curriculum and validating its effectiveness.

        Speaker: Prof. Paula Heron (University of Washington)
      • 1:45 PM
        Report on the 2016 Canadian Conference for Undergraduate Women in Physics (CCUWiP) and partnership development with the American Physical Society organization 15m
        The third edition of the Canadian Conference for Undergraduate Women in Physics (CCUWiP) series was held at Dalhousie University on 8-10 January 2016. A conference report for this 2016 edition will be presented as well as statistics from the past three editions held in Canada so far. The second part of this talk will present the status of the ongoing work to develop a long-term partnership with the US American Physical Society CUWiP organization.
        Speaker: Brigitte Vachon (McGill University (CA))
      • 2:00 PM
        My research in computational atomic physics 15m

        In atomic physics, the many-body problem is computationally challenging. When theory is well understood, accurate calculations can predict results that may be difficult to measure experimentally. For heavy elements or highly ionized systems, relativistic and quantum electrodynamic effects, not to mention nuclear effects, are less well understood and computation can assess the limitation of theory when results are compared with those from experiment.

        This talk will describe how an honours degree in mathematics and chemistry from the University of British Columbia led to research in computational atomic physics.

        Speaker: Charlotte Froese Fischer (NIST)
      • 2:15 PM
        Advancing Women in Science and Engineering: 2016 Update of the NSERC Chair for Ontario 30m

        Chairholder Catherine Mavriplis will give an overview of the activities of the NSERC / Pratt & Whitney Canada Chair for Women in Science and Engineering for Ontario. As the Chair approaches the end of its term, we'll look back at the impact it has had in several areas including interdisciplinary research in Communications, Education, Sociology and History. Since the Chair program launch, over 5000 people have been engaged in direct programming through 75 events, over 70 Canadian companies have been contacted, 15 Ontario universities have coordinated outreach efforts, a strong online following has been developed (900 Twitter and over 100 LinkedIn followers, 1400 monthly web visitors), and the Chairholder has made 10 media appearances. Learn how you can get involved in this and other regional and national activities.

        Speaker: Prof. Catherine Mavriplis (NSERC - Pratt & Whitney Chair for Women in Science and Engineering, Department of Mechanical Engineering, University of Ottawa)
    • 3:00 PM 3:45 PM
      T-PLEN Bruker BioSpin Plenary Session - Russell Jacobs, Beckman Inst./Caltech / Session plénière Marion 150

      Marion 150

      University of Ottawa

      • 3:00 PM
        Uses and abuses of μMRI and simultaneous μPET/μMRI: A Chemists talks with Physicists about Biology 45m
        Like any technology, μMRI and μPET have appropriate and inappropriate uses. I will discuss why one might bother with either; then cover a range of applications: how 3D atlas of mouse and quail can be created from high resolution MR images; delve into how lesions and brain structure changes in mouse models of multiple sclerosis are amenable to study with MRI; describe how statistical parametric mapping (SPM) of multiple MRI brain scans of transgenic mouse models provide information about neuronal circuitry alterations. Monitoring changes in tumor physiology is an important aspect of both clinical and pre-clinical imaging – ADC, DCE and cell tracking work will be discussed. Recording of μPET and μMR images simultaneously is a recent development with a host of uses and abuses – work in mouse models of atherosclerosis and oncology require the sensitivity of μPET and resolution with anatomical context of μMRI.
        Speaker: Prof. Russell Jacobs (Beckman Institute / Caltech Brain Imaging Center)
    • 3:45 PM 4:15 PM
      Health Break (with exhibitors) / Pause santé (avec exposants) SITE Atrium

      SITE Atrium

      University of Ottawa

    • 4:15 PM 6:00 PM
      T3-1 Hadronic Structure (DNP) / Structure hadronique (DPN) Colonel By B205

      Colonel By B205

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Reiner Kruecken (TRIUMF)
      • 4:15 PM
        DNP Thesis Prize: Probing Trapped Antihydrogen: In situ diagnostics and resonant transitions 30m

        Antihydrogen is the simplest pure anti-atomic system and an excellent candidate to test the symmetry between matter and antimatter. In particular, a precise comparison of the spectrum of anytihydrogen with that of hydrogen would be an excellent test of Charge-Parity-Time symmetry. The ALPHA antihydrogen experiment is able to produce and confine antihydrogen atoms in an Ioffe-Pritchard type magnetic neutral atom trap. Once confined, resonant transitions (eg. positron spin resonance transitions, 1S - 2S transitions) in the anti-atoms can be excited. In order to determine the resonant frequencies, the magnetic field seen by the antihydrogen atoms must be measured. This presents a significant challenge because the nature of the ALPHA apparatus effectively eliminates the possibility to insert magnetic probes into the antihydrogen trapping volume. Furthermore, because of the highly inhomogeneous nature of the magnetic trapping fields, external probes will not be able to measure the relevant magnetic fields.

        To solve this problem ALPHA developed an in situ magnetometry technique based on the cyclotron resonance of an electron plasma in a Penning trap. This technique can measure the local field seen by the antihydrogen atoms and therefore determine the resonant frequency of the desired transition. With this technique ALPHA was able to perform the first ever resonant interaction with antihydrogen atoms by exciting the positron spin flip transition. This talk will present our in situ magnetometry technique, the methods used to excite and identify positron spin flip transitions in antihydrogen, and future spectroscopic measurements being pursued by ALPHA.

        Speaker: Tim Friesen (Aarhus University (DK))
      • 4:45 PM
        Recent developments in characterization of Quark-Gluon Plasma 30m
        For the past two decades, two powerful heavy ion accelerators, the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC), have ushered in a new era of high energy nuclear physics. When the temperature reaches above 200 MeV/kB, quarks and gluons are no longer confined inside hadrons. Instead, they form a plasma state. This new state of nuclear matter, Quark-Gluon Plasma (QGP), existed for about a microsecond after the Big-Bang. QGP is about a hundred thousand times hotter than the centre of a star and denser than the core of a neutron star, yet flows more freely than any known fluid. At RHIC and the LHC, collisions of heavy ions now routinely create QGP and the research is entering the precision measurement stage. To understand the properties of QGP, it is essential that we understand the many stages of relativistic heavy ion collisions theoretically which includes understanding the structure of the colliding nuclei, perturbative and non-perturbative QCD, hydrodynamics of QGP, hadronic re-scatterings and electromagnetic radiations in hot medium. In this talk, I will summarized McGill theory group's effort in exploring this extreme state of matter and what we have learned so far of its rich and often surprising properties.
        Speaker: Sangyong Jeon (McGill University)
      • 5:15 PM
        Study the collectivity and electromagnetic emissivity in a small quark-gluon droplet 15m
        Signatures associated with collective behaviour has been observed in the hadronic measurements of high multiplicity proton+lead collisions at the Large Hadron Collider (LHC), as well as in (proton, deuteron, helium-3)+gold collisions at the Relativistic Heavy-Ion Collider (RHIC). To better understand the evolution dynamics and the strongly-coupled properties of the matter created in these small systems, we present a systematic study of the hadronic observables as well as electromagnetic radiation from these collisions using a hydrodynamic framework. The validity of the hydrodynamic description is quantified using the Knudsen and the inverse Reynold's numbers. Quantitative agreement is found between theoretical calculations and existing experimental measurements. Predictions of higher order anisotropic flow coefficients, Hanbury Brown and Twiss (HBT) radii, and signals of thermal photon enhancement are proposed. They can serve as additional signatures to hunt for the existence of a hot quark-gluon plasma (QGP) during the evolution of these small collision systems. Quantitative comparisons with future experimental measurements can further constrain the extraction of the transport properties of the QGP.
        Speaker: Dr Chun Shen (McGill University)
      • 5:30 PM
        Exploring the Electromagnetic Structure of the Charged Pion and Kaon 15m
        In Quantum Chromodynamics (QCD), the elastic form factor of the charged pion is unique in that it can be rigorously calculated perturbatively in the limit of asymptotically large momentum transfer. However, the lack of a "free pion" target makes experimental studies of this quantity challenging, and one must make measurements using the virtual pion cloud of the nucleon via pion electroproduction. The kaon is a similar object, and experimental measurements of the ratio of the kaon and pion form factors versus $Q^2$ are of significant interest. This talk will describe the pion and kaon form factor program at Jefferson Lab, where experiments at 6 GeV have provided precise measurements of the pion form factor at moderate momentum transfers. Upcoming measurements using the upgraded 12 GeV beam and Hall C facilities will allow us to extend these measurements to even larger momentum transfer.
        Speaker: Garth Huber (University of Regina)
      • 5:45 PM
        De-excitation of moderately excited compound nucleus for heavy-ion collisions at intermediate energies 15m
        Heavy-ion collisions at intermediate energies generate emission sources with a large distribution of excitation energies that can reach up to 10 MeV per nucleon. Evaporation models based on Weisskopf and Hauser-Feshback theories are used to de-excite these sources. Parameters used in evaporation models come from low energy experiments and must be extrapolated to de-excite high excitation energy emission sources. A better understanding of the dependence on excitation energy for these parameters is necessary. Fusion reactions give a way to study the de-excitation of emission sources with known excitation energy. The ISAC-II accelerator at TRIUMF was used to accelerate beams of 25Na, 25Mg, 20Ne and 22Ne. Experimental data was collected using the HERACLES multidetector for these reactions: 25Na+12C, 25Mg+12C at 9.2 MeV per nucleon and 20Ne+12C and 22Ne+12C at 11.7 MeV per nucleon. For nuclear reactions in this mass and energy range, reaction mechanisms include binary collisions and fusion-evaporation events. Compound nuclei produced by fusion in these reactions have an excitation energy between 2.5 and 3.3 MeV per nucleon. This excitation energy range is characteristic of emission sources produced at intermediate energies. Experimental data is compared to simulations. Antisymmetrized Molecular Dynamics (AMD) is used to simulate the dynamical phase of the collision and GEMINI++ for the de-excitation. This analysis will constrain the excitation energy dependences in evaporation models.
        Speaker: René Roy (Université Laval)
    • 4:15 PM 5:30 PM
      T3-2 Plasma Physics and Applications (DPP) / Applications et physique des plasmas (DPP) SITE C0136

      SITE C0136

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Lora Ramunno (University of Ottawa)
      • 4:15 PM
        Deflection of laser accelerated protons due to multi-megagauss magnetic fields in high-intensity laser-plasma interactions 15m
        Self-generated magnetic fields are produced in high-intensity laser-plasma experiments from several mechanisms, including relativistic electron currents and misaligned density and temperature gradients (the Biermann Battery effect). Understanding the formation and timescales of these magnetic fields is important in several high energy density regimes ranging from astrophysical jets to the fast ignition approach to laser fusion energy. Here we will present a study of the magnetic fields produced in cylindrical geometry using wire targets (10-25µm in diameter) with the Titan laser (700fs, 50 J) at the Jupiter Laser Facility. The spatial and energy distributions of the laser accelerated protons produced in the interaction are recorded using radiochromatic film (RCF) and Thomson Parabola ion spectrometers, respectively. A cylindrical RCF stack was installed around the wire target which provided a large-angle sampling of the spatial distribution. Two well-defined bands, offset ±8-15° vertically from the laser plane and surrounding the wire azimuthally, are observed for proton energies up to 7.5 MeV. We will show that the two bands observed on the RCF can be attributed to the formation of caustics in linear proton radiography theory whereby the energetic protons are deflected due to the self-generated magnetic fields. Finally, these results will be compared with 2D and 3D Particle-in-cell (PIC) simulations which qualitatively reproduce the observed bands with magnetic fields on the order of 10 MG due to the Biermann Battery effect. *This work was supported by the U.S. DOE Office of Science, Fusion Energy Science under FWP 100182 and by SLAC Laboratory Directed Research and Development. Additional support was provided by LLNL under contract DE-AC52-07NA27344 and the U.S. DOE Office of Science, Fusion Energy Science ACE HEDLP Diagnostics.*
        Speaker: Chandra Curry (SLAC National Accelerator Laboratory/University of Alberta)
      • 4:30 PM
        Low-Frequency to High-Frequency Transition of an Atmospheric Pressure Helium Dielectric Barrier Discharge 15m
        Dielectric barrier discharge is a well-known device for its diffuse discharge capability at atmospheric pressure. In a plane parallel configuration (2 mm gas width) with solid alumina dielectrics on each electrode, a diffuse discharge will occur under proper conditions. It is the case when the driving voltage is a sinusoidal waveform oscillating at 25 kHz and the feed gas is a Penning mixture of helium with ppms of N$_2$. These conditions give rise to a glow discharge (APGD) and is typical of the low-frequency range (LF). In the same conditions, when the driving frequency is oscillating at 13.56 MHz, in the high-frequency range (HF), the discharge is no longer pulsed in nature but rather a continuous plasma fluctuating between two oscillating sheaths. This behavior is typical of capacitively coupled radio-frequency discharge (CCRF) in the $\alpha$ mode. The aim of this paper is to investigate the transition through which the discharge shifts from the LF glow discharge to the HF discharge in the RF-$\alpha$ mode. Phase-locked imaging is used as the main diagnostic. On the one hand, the discharge is no longer in a purely glow discharge mode at frequencies above 100 kHz. On the other hand, above 1 MHz, the plasma is clearly in the RF-$\alpha$ mode when the applied voltage is sufficiently high. In addition, for intermediate frequencies, in the medium frequency range (MF, defined as 0.3-3 MHz), the $\Omega$ mode can be sustained at low applied voltage. This mode, where electron heating in the bulk is the main power transfer mechanism, can only be sustained between 100 kHz and 5 MHz. Electrical measurements indicate that this discharge mode is always sustained at a power density of the order of 0.1 W/cm$^3$. Optical emission spectroscopy is used to compare the discharge modes. While the LF glow discharge and the HF discharge in the RF-$\alpha$ mode display fairly similar spectra, the spectrum of the $\Omega$ mode occurring in the MF range displays strongly different emissions. In fact, the ratio of helium emissions over impurities (mainly OH, N$_2$ and N$_2^+$) is much lower in this latter mode than in the formers. This suggests that the ratio of high-energy electrons over metastable atom density (impurities mainly depend on helium metastable atoms density) is higher in both the LF and HF discharges. In other words, the electron temperature is expected to be significantly lower in the $\Omega$ mode occurring in the MF range.
        Speaker: Jean-Sébastien Boisvert (Université de Montréal)
    • 4:15 PM 5:30 PM
      T3-3 Quantum Computing and Coherent Control (DAMOPC) / Calcul quantique et contrôle cohérent (DPAMPC) SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Joyce Poon (University of Toronto)
      • 4:15 PM
        Spins and photons: quantum optics with defect centers in diamond 30m
        Individual defects in crystalline materials can have electronic properties akin to those of isolated trapped atoms or ions. Recently, the nitrogen vacancy center, a type of defect in diamond, has emerged as as a particularly compelling example. Like atoms, these defect centers have spin degrees of freedom and and optical transitions that make them an attractive platform for building quantum information technologies. Their spin states might someday be used to store and manipulate quantum information, with photons connecting individual defects into a useful computational network or secure communication system. This talk will introduce the properties of nitrogen-vacancy defect centers relevant to such a vision, and present some recent results on the path toward creating a high-efficiency spin-photon interface using fiber-based optical microcavities.
        Speaker: Lilian Childress (McGill University)
      • 4:45 PM
        Towards correcting atmospheric turbulence effects via pump beam control in a down conversion process 15m
        Quantum Communication can be done using single photons generated via spontaneous parametric down conversion (SPDC). Since these protocols only use the signals that are collected by the receiver, the system is not as negatively affected by occasional drop outs as compared to classical communication protocols. In order to collect as many photons as possible, it is necessary to have a mechanism to guide them to the receiver. The photon pairs that are created through the process of SPDC conserve their momentum and are therefore spatially correlated. The temporal and spatial modes of the photons can be adjusted according to the specific requirements of a transmission link. The correction for tip/tilt errors in pointing is usually performed on the transmitted beam itself. However, due to the correlations between the pump beam and the down converted photons, it is possible to manipulate the pump beam instead of the transmitted arm to achieve a similar effect. This technique can be very useful for Quantum Communication protocols since interfering with the transmitted arm can cause alterations to the polarisation and other properties and thus destroy the encoding in the photon. By manipulating the pump, the transmitted arm remains untouched but is guided towards the receiver for a higher collection efficiency. We have developed a theoretical model to calculate the effect of varying the pump beam angle into the nonlinear crystal on the signal photon while holding the idler photon in a fixed position. The technique we use to observe these correlations is based on an array of single photon avalanche diodes (SPAD), offering temporal and spatial resolution on a single photon level. Here we investigate the possibility to control the spatial characteristics of one of the down converted photons by altering the direction of the pump beam.
        Speaker: Mr Christopher Pugh (University of Waterloo/Institute for Quantum Computing)
      • 5:00 PM
        The Promise of Quantum Nonlinear Optics 30m
        This presentation first reviews the historical development of the field of nonlinear optics, starting from its inception in 1961. It then reviews some of its more recent developments, including especially how nonlinear optics has become a crucial tool for the developing field of quantum technologies. Fundamental quantum processes enabled by nonlinear optics, such as the creation of squeezed and entangled light states, are reviewed. We then illustrate these concepts by means of specific applications, such as the development of secure communication systems based on the quantum states of light in the form of states that carry orbital angular momentum. Light can carry angular momentum both by means of its spin angular momentum (as manifested for example in circular polarization) and by means of its orbital angular momentum (OAM), whose origin is a helical structure of its wavefront. The orbital angular momentum of light has recently been recognized to constitute a crucial attribute for many photonic technologies, including the trapping and manipulation of small particles and for multiplexing in optical telecommunication. In this presentation we review some of the fundamental properties of OAM including its quantum features such as entanglement. We then go on to describe a secure telecommunication system in which information is encoded in OAM, and which can carry more than one bit of information per photon.
        Speaker: Robert Boyd (University of Ottawa)
    • 4:15 PM 5:30 PM
      T3-4 Quantum Gravity and Quantum Cosmology (DTP) / Gravité quantique et cosmologie quantique (DPT) Colonel By D103

      Colonel By D103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Prof. Ariel Edery (Bishop's University)
      • 4:15 PM
        Cosmology from Quantum Gravity 30m
        I will explain how the large-scale cosmological dynamics can be obtained from the hydrodynamics of condensate states of quantum gravity (to be specific, isotropic group field theory condensate states in the Gross-Pitaevskii approximation). The correct Friedmann equations are recovered in the semi-classical limit for appropriate choices of the parameters in the action for the group field theory, and quantum gravity corrections arise in the high-curvature regime causing a bounce which generically resolves the big-bang and big-crunch singularities.
        Speaker: Edward Wilson-Ewing (Max Planck Institute for Gravitational Physics (Albert Einstein)
      • 4:45 PM
        Basic elements of loop quantum gravity 30m
        The main idea of loop quantum gravity (LQG) is to develop a canonical quantum theory of general relativity (GR). In this talk, I will give a pedagogical account of LQG aimed at physicists who are unfamiliar with the field. The main focus will be on basic elements of the construction and how these relate to more familiar objects in GR and quantum field theory.
        Speaker: Jonathan Ziprick
      • 5:15 PM
        A Non-Local Lorentz-Invariant Quantum Spacetime 15m
        From the EPR paper in 1935, to Bell’s theorem in the 1960s, to Aspect’s EPR experiment in the 1980s and its recent refinements demonstrating km range correlations, it has become increasingly clear that entangled quantum mechanical systems are inherently nonlocal. EPR experiments highlight the theoretical divergence between quantum mechanics (QM) as a theory of matter in need of a theory of spacetime and special relativity (SR), for which the converse is true. Essentially by definition, quantum nonlocality is incompatible with an interpretation of Minkowskian spacetime as a single 4D metric space, in which all relations between points are defined by a metric. *A priori*, one might expect that QFT, as a successful theory incorporating both relativistic and quantum concepts, would provide a conceptual unification of spacetime and quantum theory, but this has not proven to be the case. Also, despite the wide variety of interpretations of quantum mechanics, no consensus ontology has emerged. Quantum nonlocality demands some form of nonlocal spacetime: we consider here a spacetime consisting of multiple coexisting metric spaces. Within any one space its own metric ensures locality, but between spaces no metric is defined, so interactions between points in different spaces are inherently non-local. Following this (while honoring Lorentz invariance), we outline a new proposal in which special relativistic spacetime is reinterpreted as a superposition of multiple 4D spaces. Each space contains unique content, described by a complex-valued density function. By then postulating a coupling between spaces, quantum mechanical features such as non-locality, superposition and wave behavior naturally emerge. Remarkably, Planck’s constant is shown to govern the coupling between spaces, revealing a fundamental interdependence between spacetime and quantum concepts. The resulting picture is of a set of superposed metric spaces tightly coupled by a ‘quantum glue’ in proportion to m/h. We show that this is compatible with existing SR & QM theories, with however momentum as the fundamental physical basis of quantum superposition, and so having significant implications for the quantum ‘measurement problem’. The coexistence of multiple spaces necessitates a redundancy of physical description, providing an explanation for the origin of gauge theories.
        Speaker: Jonathan Sharp (University of Alberta)
    • 4:15 PM 5:30 PM
      T3-5 Cosmic Frontier: Dark Matter III (PPD) / Frontière cosmique: matière sombre III (PPD) Colonel By D207

      Colonel By D207

      University of Ottawa

      • 4:15 PM
        SuperCDMS and CUTE at SNOLAB 15m
        The Super Cryogenic Dark Matter Search (SuperCDMS) experiment uses cryogenic semiconductor detectors to search for Weakly Interacting Massive dark matter Particles (WIMPs). After more than a decade of operations of CDMS and SuperCDMS and a sequence of world leading results, the experimental setup in the Soudan underground laboratory in Minnesota is being decommissioned and SuperCDMS will move to SNOLAB near Sudbury, ON for its next phase. In this talk I will describe the status of the preparations for the construction of the new experimental setup at SNOLAB, as well as the plans for a well shielded Cryogenic Underground TEst facility (CUTE) to be installed at SNOLAB next to SuperCDMS.
        Speaker: Dr Wolfgang Rau (Queen's University)
      • 4:30 PM
        Upgrading the Shield of the GIOVE High-purity Germanium Detector 15m
        The GIOVE (Germanium Inner-Outer Veto) detector is a highly sensitive germanium spectrometer used to screen materials for trace amounts of radioactivity. Material screening is an important aspect of the construction rare-event experiments such as GERDA and XENON, which require extremely low background levels. GIOVE is located at the Max Planck Institute for Nuclear and Particle Physics in Heidelberg, Germany, housed in the lower level laboratory at a depth of 15$\,$m water equivalent. The extensive shield and unique passive-active veto system allows the detector to achieve sub-mBq sensitivities despite its shallow depth. A variety of new shield configurations and materials were investigated to further improve the sensitivity of the detector. Monte Carlo simulations demonstrate that substantial reductions in the neutron and gamma-ray spectrum at the diode may be possible by either rearranging the existing shield layers or making use of new materials tungsten and boron carbide. The results indicate that new materials and construction techniques may allow GIOVE to achieve higher sensitivity levels and suggest potential improvements to current material screening methods available to rare-event experiments.
        Speaker: Jennifer Mauel (Queen's University)
      • 4:45 PM
        The NEWS-SNO project 15m
        The existence of Dark Matter in our Universe is nowadays well established, however, its exact nature still remains unknown. The goal of the NEWS-SNO (New Experiments with Spheres in SNOLAB) project is to search for particle candidates in mass regions not yet accessible by existing experiments. The planned NEWS-SNO detector consists of a spherical TPC (time-projection-chamber) out of ultrapure copper ,filled with up to 10bar of CH4 and He gas mixtures which is read out with one small central sensor set at high voltage. Thanks to the very light nuclear mass of the employed targets as well as its very low energy threshold, the detection of spin-independent interacting WIMPS down to masses of 0.1 GeV/c2 is aimed at. This mass range for Dark Matter particles is motivated in a number of models based on dark sector forces and, e.g., millicharged models. Changing the nature and/or mix of gas, the pressure, the HV, the sensor are knobs that could be used to check a possible dark matter like signal. An overview and status of the planned experiment at SNOLAB and results of the prototype detector SEDINE operated with Neon gas in the Laboratoire Souterrain de Modane underground laboratory in France will be given.
        Speaker: Dr Gilles Gerbier (Queen's University)
      • 5:00 PM
        Spectroscopic and time-resolved measurements of the fluorescence of pyrene at low temperatures for noble liquid particle detectors 15m
        Pyrene is an interesting material because of its wavelength shifting properties. When irradiated with ultraviolet light, pyrene will emit light in the visible wavelengths. This property could be useful for experiments looking to observe scintillation light from noble gases such as argon and neon, which are popular target materials for dark matter direct detection experiments. Noble gases scintillate in the ultraviolet, and wavelength shifting materials are used to generate visible light observable with standard light detectors. These noble gas detectors are usually operated at cryogenic temperatures, so the performance of pyrene as a wavelength shifter at low temperatures is relevant to its use in such experiments. Relatively long fluorescence lifetime of pyrene provides a possibility to use pulse shape discrimination for rejection of backgrounds caused by alpha activity in regions of the detector where light collection is poor. We have studied the light emission of pyrene under ultraviolet light excitation at Queen's University using an optical cryostat down to 3.4 K. The high vapour pressure of pyrene causes thin films to evaporate when exposed to the vacuum required to achieve colder temperatures, so we have developed samples of acrylic with dissolved pyrene to prevent the loss of material. Photomultiplier tubes combined with the multiple photon-counting coincidence (MPCC) method allow us to extract the time structure of pyrene fluorescence in response to nanosecond pulses of vacuum ultraviolet light. We also use a spectrometer to measure the wavelength spectra of the emitted light at multiple temperatures to understand its performance. We present the results of both time-resolved and spectroscopic studies of pyrene dissolved in acrylic at low temperatures, including those of noble liquids.
        Speaker: Michael Clark (Queen's University)
      • 5:15 PM
        X-ray Detectors for the Unique Third Forbidden Decay of Potassium-40 15m
        Enigmatic dark matter is responsible for 26% of the total mass-energy in the known universe. Since 1997, the DAMA/LIBRA experiment has claimed to have the first direct evidence for the observation of dark matter. One major source of background for this experiment is the 40K isotope. The chemical similarity between potassium and sodium is why trace amounts can be found in the NaI scintillators that DAMA/LIBRA uses as detectors. This contamination presents a challenging background that makes any interpretation of the dark matter signal difficult. 40K occurs in potassium (~0.0117%), which is a contaminant even in ultra-pure NaI(Tl). Two decay channels of 40K are of particular consequence. The first is the electron capture (EC*) into an excited state of 40Ar* which quickly de-excites to ground level. This releases a 2.95 keV x-ray or a 2.5 keV auger electron. A 1460 keV gamma ray is released in coincidence. There is also an electron capture (EC) directly to the ground state of 40Ar, which only releases a 2.95 keV x-ray (or 2.5 keV Auger Electron). Both decays contributes to the ~3 keV bump seen in the data by DAMA/LIBRA and are a factor in their extraordinary claim. DAMA/LIBRA is able to remove a fraction of the decays to the excited state by tagging the 1460 keV gammas. However, the branching ratio to the ground state is not known. This branching ratio will help reduce and understand the background in the dark matter signal region of the DAMA/LIBRA experiment. In addition, this will be the first observation of a unique third forbidden decay. We report on the performance of a Large Area Avalanche Photo Diode (LAAPD) for the direct measurement of the low energy x-rays and electrons. By observing multiple sources and x-ray fluorescence the LAAPD can be studied and characterised for the 40K energy range. Their viability for the use in a dedicated measurement of the EC branching ratio will then be determined.
        Speaker: Mr Matthew Stukel (Queens University)
    • 4:15 PM 5:30 PM
      T3-6 Panel Discussion - Women in Physics: What's in it for both men and women? (CEWIP) / Table ronde - Les femmes en physique : qu'en retirent les hommes et les femmes? (CEFEP) Colonel By C03

      Colonel By C03

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON

      Panelists: Svetlana Barkanova (Acadia University), Melanie Campbell (University of Waterloo), Charlotte Froese Fischer (NIST), Adriana Predoi-Cross (University of Lethbridge), and Michael Steinitz (St. Francis Xavier University).

      Convener: Shohini Ghose (Wilfrid Laurier University)
      • 4:15 PM
        Women in Physics: What's in it for both men and women? / Table ronde - Les femmes en physique : qu'en retirent les hommes et les femmes? 1h 15m

        Panelists: Svetlana Barkanova (Acadia University), Melanie Campbell (University of Waterloo), Charlotte Froese Fischer (NIST), Adriana Predoi-Cross (University of Lethbridge), and Michael Steinitz (St. Francis Xavier University).

    • 4:15 PM 5:30 PM
      T3-7 Applied Physics in Non-Academic Environment (DIAP-DIMP) / La physique hors université (DPIA-DPIM) Colonel By B012

      Colonel By B012

      University of Ottawa

      Convener: Robert Fedosejevs (University of Alberta)
      • 4:15 PM
        Working in an applied R&D center : INO as an example 30m
        INO is an innovation house, it is home to the largest concentration of skill in the applied optics/photonics field and serves clients of all sizes from all parts of Canada and around the world. INO offers a complete range of integrated services to clients of all descriptions in every field of industrial activity. It also possesses a variety of technologies and innovative processes based on a strong IP portfolio. These assets represent unique business opportunities for companies wishing to commercialize them. Innovation is a key word nowadays and requires a good balance between creativity and realism. Being a physicist in a non-academic environment is an interesting challenge. Both the organization and the researcher point-of-view will be presented.
        Speakers: Dr Martin Bolduc (INO, Québec), Dr Pierre Galarneau (INO, Québec)
      • 4:45 PM
        Le physicien et le génie des matériaux - Physicists in Materials Engineering 30m
        The strong basic training of physicists allows them to grasp important scientific and technological issues encountered in materials engineering. Physicists have an understanding of the fundamental mechanisms that govern the behavior and properties of materials while processing and using them in various applications. This understanding enables them to contribute effectively in multidisciplinary R&D teams by bringing a different perspective to their fellow engineers. In this presentation, we will see a series of practical examples of career opportunities facing physicists in the manufacturing industry, national laboratories and engineering departments. Several examples will be drawn from my career conducted in close interaction with Canadian industry over the past 35 years. La formation de base du physicien lui permet de saisir des enjeux scientifiques et technologiques importants rencontrés en génie des matériaux. Il a une compréhension des mécanismes fondamentaux qui régissent le comportement et les propriétés des matériaux lors de leur mise en forme et lors de leur utilisation. Cette compréhension lui permet de contribuer de façon efficace à des équipes multidisciplinaires de recherche et développement en amenant une perspective différente de ses collègues ingénieurs. Dans cette présentation, nous verrons un ensemble d’exemples illustrant de façon pratique les possibilités de carrière du physicien tant au sein de l’industrie manufacturière, de laboratoires nationaux ou de départements de génie. Plusieurs exemples seront tirés de mon parcours professionnel mené en étroite interaction avec l’industrie canadienne au cours des 35 dernières années.
        Speaker: Prof. Christian Moreau (Université Concordia)
      • 5:15 PM
        The Canadian Atmospheric Tomography System (CATS) 15m

        C. Haley1, D. Degenstein2, R. Cooney3, and A. Bourassa2

        1 Honeywell Aerospace
        2 University of Saskatchewan
        3 Canadian Space Agency

        The Canadian Atmospheric Tomography System (CATS) is a UV/visible/near-IR spectrometer designed to measure limb-scattered sunlight to derive vertically-resolved concentrations of O3, NO2, and BrO and aerosol extinction from the Upper Troposphere through the Stratosphere. CATS is a follow-on to the Optical Spectrograph and Infrared Imager System (OSIRIS) instrument currently in operation on the Odin satellite. In addition to monitoring the stratosphere and extending the long time-series provided by OSIRIS, CATS will focus on the study of fine scale phenomena in the Upper Troposphere/Lower Stratosphere (UTLS) region. To accomplish this new goal, the current CATS design incorporates the following modifications over OSIRIS:
        1) Increased spectral range, focussed on an improved aerosol product.
        2) Better spectral resolution, aimed at improved NO2 and BrO data products.
        3) Improved vertical resolution and sampling, important for measurements in the UTLS region.
        4) Better horizontal (along-track) sampling, to allow a tomographic retrieval approach to be used.
        The current status of the CATS instrument design and development will be reviewed, highlighting the changes from the OSIRIS instrument design, the main outstanding technical risks, and the current development activities. Mission implementation options on either a dedicated microsatellite or as a payload on a small satellite will also be presented.

        Speaker: Dr Craig Haley (Honeywell Aerospace)
    • 4:15 PM 5:30 PM
      T3-8 Thin Films I (DSS-DCMMP) / Couches minces I (DSS-DPMCM) SITE J0106

      SITE J0106

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Mark Gallagher (Lakehead University)
      • 4:15 PM
        Epitaxially stabilized thin films of the potentially multiferroic materials ε-Fe2O3 and ε-AlxFe2-xO3. 15m
        ε-Fe2O3 is a metastable intermediate phase of iron (III) oxide, between maghemite (γ-Fe2O3) and hematite (α-Fe2O3). Epsilon ferrite has been investigated essentially because of its ferrimagnetic ordering with a Curie temperature of circa 500 K. However, given its orthorhombic crystal structure that belongs to the non-centrosymmetric and polar space group *Pna21*, it should exhibit ferroelectric behavior along with magnetoelectric coupling of the two orders (potentially making it one of the few room temperature multiferroic materials). Moreover, the material is characterized by strong magnetic anisotropy, resulting in a ferromagnetic resonance (FMR) frequency in the THz range in the absence of magnetic field and at room temperature. This is of particular interest given its potential use in short-range wireless communications (e.g. 60GHz WiFi) and ultrafast computer non-volatile memories. Due to its metastable nature, ε-Fe2O3 needs to be stabilized at room temperature: to date such feature has been obtained mainly by synthesizing it by sol-gel as nanoparticles embedded inside a SiO2 matrix, with the stabilization mechanism being either pressure or size confinement (or both). Recently however, deposition of epitaxial thin films of ε-Fe2O3 on SrTiO3 (111) was demonstrated; in this case the stabilization is thought to be due to both epitaxial strain and interface interaction between the substrate and the film. We report the growth by Pulsed Laser Deposition of epitaxial thin films of ε-Fe2O3 and ε-AlxFe2-xO3 on different single crystal substrates, both oxides (SrTiO3, LaAlO3, LSAT, and YSZ) and non-oxides (single crystal Silicon), and discuss the influence of the chosen substrate and of aluminum doping on the structural, magnetic and dielectric properties. In particular, we focused our attention on the effect of Al inclusion inside the ε-Fe2O3 lattice, which should result (i) in the improvement of the electric properties, given the good ferroelectric properties of the isostructural AlFeO3, and (ii) in a lowering of the FMR frequency due to non-magnetic nature of Al.
        Speaker: Luca Corbellini (Institut National de la Recherche Scientifique, Centre EMT, Varennes)
      • 4:30 PM
        **WITHDRAWN** Neutron Reflectometry: A non-destructive probe for in-situ corrosion monitoring in Cu-Ni (90/10) alloy 15m
        Neutron Reflectometry (NR) is an ideal technique to study chemical reactions at surfaces and interfaces because it is a non-destructive technique which can determine in-situ the chemical profile in a film with nanometre resolution. Therefore, NR can provide information on the metal and oxide layer thickness and the changing interfaces between metal and oxide layer as well as oxide layer and an aqueous environment, thereby investigating the corrosion process on the atomic scale. The Cu-Ni (90/10) alloy is an interesting material from its corrosion resistance property and is being used in many industries including marine and nuclear applications. The accelerated corrosion of this alloy in seawater under certain conditions has been attributed to the breaking and removal of the passive Cu2O/CuO layer. According to this picture, the density of the Cu2O/CuO passive layer, as well as the film thickness, should start changing at the onset of the corrosion process. To date, this phenomenon has not been observed directly and in situ. In this study, we used NR to monitor the surface corrosion to get insight into the passive layer modification during the very early stages of corrosion. We prepared 60 nm thick Cu90Ni10 films on Si wafers using DC magnetron sputtering and exposed them to simulated seawater and to a similar seawater but contaminated with sulphur, and measured neutron reflectivity as a function of time. The first experiment (i.e. without sulphur) showed that the reaction at the surface starts after a few minutes and progresses slowly. In contrast, in sulphur polluted seawater (10 ppm S) the reaction was much faster.
        Speaker: Syed Bukhari (Candian Nuclear Laboratories (CNL))
      • 4:45 PM
        **WITHDRAWN** Growth of Cu-Ni (90/10) films by DC magnetron sputtering 15m
        It is a common fact about alloys that surface chemical composition varies from the bulk in terms of elemental ratio and chemical state of the elements which can affect their material performances. That’s why deposition of alloy films is very challenging. We prepared CuNi (90/10) alloy thin films by D.C. magnetron sputtering on Si(111) substrates and studied the effect of deposition times and sputtering powers on their surface and bulk chemical compositions and microstructures. According to XRD studies, all deposited films were composed of single phase CuNi (90/10) alloy and predominantly (111) textured. Crystallite sizes increased linearly with the increase in deposition times and sputtering powers. SEM studies revealed that sputtering powers have relatively stronger influence on the surface roughness and island formation as compared to the deposition times. Our XPS analysis showed slight Ni enrichment on the surface and presence of Ni2O3 along with NiO strongly which strongly suggested existence of a surface defect in all films. Furthermore, there was a clear evidence of presence of CuO along with Cu2O as Cu2p core level had a strong satellite peak. Neutron Reflectometry measurements, indicated that the film thickness increases linearly both with deposition times and sputtering times.
        Speaker: Dr Syed Bukhari (Canadian Nuclear Laboratories)
      • 5:00 PM
        Plasmonic colouring of noble metals via picosecond laser pulses 15m
        We report the creation of angle independent colors on silver due to plasmonic effects arising from random nanoparticle distributions induced by picosecond laser exposure. The color is determined by the total accumulated fluence on the surface. This is valid for all combinations of laser parameters producing the same total accumulated fluence. Both spectral and extra-spectral colors can be obtained. Finite-difference time-domain computations carried out on a high-performance computing system identify the role of each geometrical parameter leading to understanding of color formation. Absorptive plasmonic resonances in heterogeneous nanoclusters are found to be key in the color formation. We also simultaneously report the angle-independent coloring of pure gold with colors covering the entire spectral and extra-spectral region. To our knowledge this represents a world first in the laser coloring of metals.
        Speaker: Jean-Michel Guay (University of Ottawa)
      • 5:15 PM
        Novel Phases of High-Tc Cuprates in Superoxygenated and Heterostructured Thin Films* 15m
        Thin films of transition-metal oxides, by virtue of their high surface-to-volume ratio, tend to have very different thermodynamic phase stability than in bulk form. When these films are grown epitaxially on perovskite substrates, the heteroepitaxial mismatch can also induce strong interfacial strains resulting in intergrowths of novel lattice defects [1]. We apply these two concepts of nanoscale materials synthesis to the Y-Ba-Cu-O family of cuprates, in an effort to stabilize novel cuprate phases with very high superconducting critical temperature (Tc). Pulsed laser-ablated deposition is used to grow thin layers of YBa2Cu3O7 (YBCO) epitaxially on and between various cubic perovskites, ranging from insulating titanates to half-metallic maganites. The thin films and heterostructures are also subjected to superoxygenation by annealing under 500 atm of O2 pressure. Atomic-scale transmission electron microscopy and electron energy loss spectroscopy revealed unambiguous evidence for three novel phases of Y-Ba-Cu-O in the nominally YBCO layers. These phases are characterized by either triple-CuO chains, BaO layers within double-CuO chains or extra Y-O layers within the CuO2-Y-CuO2 bilayer; their formation can be attributed to the superoxygenation and heteroepitaxial strain. We discuss the likelihood that these novel cuprate phases have enhanced Tc, in light of a recent pump-probe spectroscopy study [2] of YBCO showing pairing enhancement by dynamic increase of the CuO2 bilayer thickness. [1] H. Zhang, N. Gauquelin, G. A. Botton, J. Y.T. Wei, Appl. Phys. Lett. 103, 052606 (2013). [2] W. Hu, S. Kaiser, D. Nicoletti, C. R. Hunt, I. Gierz, M. C. Ho mann, M. Le Tacon, T. Loew, B. Keimer and A. Cavalleri, Nature Materials 13, 705 (2014). *Work supported by NSERC, CFI-OIT, and the Canadian Institute for Advanced Research.
        Speaker: John Wei (University of Toronto)
    • 4:15 PM 5:30 PM
      T3-9 Atmospheric and Space Physics (DASP) / Physique atmosphérique et de l'espace II (DPAE) SITE H0104

      SITE H0104

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: james Drummond (Dalhousie University)
      • 4:15 PM
        New Observation of the Polar Wind in the Topside Ionosphere 15m
        The theoretical prediction of the “classical” polar wind dates back to the works of Banks et al., Lemaire et al., Marubashi, Nishida, and other authors in the late sixties and early seventies. Since then, direct in-situ observations of the polar wind have been made on a number of satellites above the topside ionosphere, notably ISIS-2, Akebono, and DE-1, at altitudes of 1400–50,000 km. In this paper, we present the first in-situ observation of the polar wind inside the topside ionosphere on the Enhanced Polar Outflow Probe (e-POP) down to 600 km, and we compare our low-altitude observation with earlier observations at higher altitudes as well as theoretical predictions.
        Speaker: Andrew Yau (University of Calgary)
      • 4:30 PM
        On the validation of Swarm TII and LP data 15m
        The Thermal Ion Imagers (TII) on the Swarm satellites measure ion distribution functions which carry information about ion temperature in the topside ionosphere. Ion temperature, which is obtained from the second moments of the imaged ion distribution, requires validation. One way to evaluate the accuracy of the TII ion temperature, as well as electron temperatures and densities measured by the Langmuir probes (LP), is to study their consistency with a physics-based model of energy exchange between electrons, ions, and neutrals. We first assess the validity and accuracy of the method of topside ion temperature estimation from the energy balance equation using a physics-based ionosphere model at low and middle latitudes. Next, since the method depends on the LP data, the measurements of electron density and temperature are compared with corresponding measurements from incoherent scatter radars. In addition, the electron density data are compared with those obtained from COSMIC GPS radio occultation globally. Possible adjustments to the data are proposed.
        Speaker: Levan Lomidze (University of Calgary)
      • 4:45 PM
        Dynamic analysis of the polar ionosphere during scintillation: towards an optimization of the detrending frequency 15m
        In the context of scintillation, the chaotic behavior of the ionospheric plasma in the high latitude region is investigated using the GPS (Global Positioning System). The study is carried out with the use of the data from the Canadian High Arctic Ionospheric Network (CHAIN). The L1 GPS signal, sampled at 50 Hz, is characterized and analyzed. The statistical analysis is performed on both components of the signal, namely the amplitude and the phase. The Tsalis entropy is constructed for the signal, and along a multiscale analysis, criteria for the determination of the optimum detrending frequency, delimiting the scintillation components from the background variations, are defined. I will present the method used in this study and discuss the importance of the detrending frequency in the mitigation process of the effect of the ionospheric scintillation on the Global Navigational Satellite System (GNSS).
        Speaker: Hichem Mezaoui (University of New Brunswick)
    • 5:30 PM 6:45 PM
      CAP Past Presidents' Meeting / Réunion des anciens présidents de l'ACP Colonel By B202

      Colonel By B202

      University of Ottawa

      Convener: Robert Fedosejevs (University of Alberta)
    • 5:30 PM 6:45 PM
      Carl Zeiss Canada Student-Industry Meet & Mingle / Session de réseautage industrie-étudiants SITE G0103

      SITE G0103

      University of Ottawa

      SITE Building, 800 King Edward Ave, Ottawa, ON
      Convener: Kirk Michaelian (Natural Resources Canada)
      • 5:30 PM
        A Journey to the Dark Side ... Some alternate uses of your physics degree 30m

        Bio
        Neil Rowlands obtained his B.Sc (Engineering Physics) from the University of Alberta in 1985 and his Ph.D. (Astronomy) from Cornell University in 1991. At Cornell, he participated in the construction and use of infrared instrumentation for the Kuiper Airborne Observatory and the 5m Hale telescope at Mt. Palomar. After post-doctoral fellowships at the Université de Montréal, and at the Canada Centre for Remote Sensing where he worked with infrared instrumentation, he joined CAL Corporation (Ottawa, ON), now Honeywell Aerospace, as an electro-optical engineer. Since 1995 he has been developing space-borne scientific instrumentation for the space physics, atmospheric sciences and astronomy communities. He is currently a Staff Scientist at Honeywell in Ottawa. He has been working on the Canadian contribution to the James Webb Space Telescope (JWST) project, the Fine Guidance Sensor (FGS/NIRISS), since 1997.

        Speaker: Dr Neil Rowlands (Honeywell Aerospace)
    • 5:30 PM 6:45 PM
      Department Leaders Business Meeting / Réunion d'affaires des directeurs de départements Desmarais 12th Floor- 12-102

      Desmarais 12th Floor- 12-102

      University of Ottawa

      Convener: Donna Strickland (University of Waterloo)
    • 7:00 PM 9:30 PM
      CJP Editorial Board Meeting / Réunion du comité de rédaction de la RCP Mamma Teresa Ristorante

      Mamma Teresa Ristorante

      300 Somerset St W, Ottawa, ON K2P 2C2 Phone:+1 613-236-3023 Menu: mammateresa.com
      Convener: Michael O. Steinitz (St. Francis-Xavier University)
    • 7:00 PM 10:00 PM
      DAMOPC Poster Session with beer / Session d'affiches avec bière DPAMPC SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: Matt Reid (University of northern british columbia)
      • 7:00 PM
        A Fine Pointing System Suitable for Quantum Communications on a Satellite 2m
        In order to perform quantum key distribution (QKD) to a moving satellite, a fine pointing system is needed to ensure the collection of as many photons as possible. Since QKD only relies on the number of detected photons, any lost signal will not reduce security but will decrease the amount of key generated. A dedicated fine pointing system would help reduce the amount of photons that are lost within the satellite after collection by the primary optics. We have designed a novel fine pointing apparatus, along with the Institute national d’optique and Neptec Design Group, to assist photon coupling into multimode fibres after the photons undergo polarisation analysis on a QKD receiver. This system keeps in mind weight and volume restrictions imposed by future space applications. It also mitigates polarisation error through the design of custom mirror coatings. Pointing accuracy of the APT is sufficient to allow QKD to be performed even with angular disturbances to the receiver telescope and fluctuations of the laser beacon. This presentation will outline the APT design concept, summarize the fine pointing performance of the unit as demonstrated through various laboratory tests, and discuss plans to use the device to perform outdoor QKD trials with receivers aboard trucks, boats or aircraft.
        Speaker: Christopher Pugh (University of Waterloo)
      • 7:02 PM
        On a minimal set of separable measurements for a pure state determination in a two-qubit system. 2m
        **On a minimal set of separable measurements for a pure state determination in a two-qubit system.** I.D. Ivanovic, Department of Physics, Carleton University In this note I will address the problem of minimum set of separable measurements necessary to determine a pure state of a two-qubit system. A set of measurements for a complete state determination of a 2x2 system was given in[1], later it was expanded to arbitrary 2^(⊗n) in [2], and 2x2 was experimentally confirmed in [3]. Besides, a question of determining an unknown pure state was always present, and as recently as this year, it was discussed e.g. in [4] and [5]. In [5] a set of measurements was suggested aiming at determining an unknown pure state P,({P≥0,tr(P)=1,P^2=P }) of a two-qubit system. The set of nine operators allows pure state determination. The set of seven expected values for operators σ_i⊗σ_j ,tr(Pσ_i⊗σ_j ), plus normalization, where σ_i∈{I,σ_x,σ_y,σ_z } are Pauli matrices, { σ_x⊗I,σ_y⊗σ_x ,σ_y⊗σ_y ,σ_y⊗σ_z ,σ_z⊗σ_x ,σ_z⊗σ_y ,σ_z⊗σ_z } does not. It is shown, by construction, that this particular choice of operators is inadequate. Some other possible solutions are discussed. Email: igor@physics.carleton.ca References: [1] I.D. Ivanovic , in CISM Courses and lectures No.294 Proceedings of “Information complexity and control in quantum physics”, Editors Blaquiere et al –Udine,1985, Springer Verlag 1987, p 67-76. [2] W. K. Wooters and B. D. Fields, Ann. Phys (NY) 191 (189) p.363 [3] Adamson R.B.A and A.M. Steinberg arxiv: 0808.0944v4[quant-ph] [4] Chapman R. J. et al arxiv:1602.04194v1[quant-ph] [5] Xian Ma, et al arXiv: 1601.05379v1 [quant-ph]
        Speaker: Dr Igor Ivanovic (Carleton University)
      • 7:04 PM
        Detection of Metastable Particles Using Solid N2 at 10K 2m
        Metastable particles produced in the interaction of electrons of carefully controlled energy with thermal gaseous target beams in a crossed beam set-up have been studied in the energy range from threshold to 300 eV. The e-beam is pulsed and the metastables produced drift to a solid nitrogen detector held at 10 K. Here they transfer their energy to states which radiate. The resultant photons are detected using a photomultiplier-filter combination. Time-of-flight techniques are used to separate these photons from prompt photons produced in the initial electron collision. With N2 as both target and detection matrix, the emission is strongest in the green but still significant in the red spectral region. Excitation functions will be presented together with threshold measurements. These help to identify the metastable states being observed and the excitation mechanisms which are responsible. The authors thank NSERC and CFI, (Canada), for financial support.
        Speaker: Dr Wladek Kedzierski (University of Windsor)
      • 7:06 PM
        Modelling seeded stimulated Brillouin scattering (SBS) and dispersion 2m
        The dominant nonlinear effect within standard telecommunication fibers is stimulated Brillouin scattering (SBS). SBS can grow from a spontaneous process or it can be seeded for applications such as fiber amplifiers or fiber sensors. The spontaneous process occurs when a pump signal is scattered by thermal fluctuations within the fiber, resulting in a frequency downshifted Stokes signal. The seeded process involves injecting the counterpropagating pump and Stokes signals into their respective ends of the fiber and not relying on the random scattering from thermal noise for initiation. In applications that implement a seeded configuration, spontaneous generation is usually irrelevant and therefore SBS occurs primarily when the pump and Stokes overlap and drive stimulated scattering. Numerical models typically only incorporate attenuation and SBS within their equations while neglecting dispersion and other nonlinear effects. Under specific conditions it is possible for both pump and Stokes waves to travel significant distances, during which they may experience dispersion, before overlapping and interacting. We are presenting a hybrid numerical method that separates the propagation and interaction regimes within the fiber. The propagation of the pump and Stokes up to the interaction region is accomplished using a split step method which allows attenuation, dispersion, and nonlinear effects other than SBS to be included. Within the interaction region dispersion, SBS, and other nonlinear effects are evaluated through an implicit Runga-Kutta integration. This method is uniquely suited to evaluate situations with large propagations with relatively short interaction regions, allowing the pump and Stokes pulses to be altered by dispersive effects before coupling and transferring energy through SBS.
        Speaker: Scott Newman (Univeristy of Ottawa)
      • 7:08 PM
        The Effect of Electrolyte Additives on Crystallite Orientation in Galvanic Cu Deposits on ⟨111⟩, ⟨100⟩ and ⟨110⟩ Cu Surfaces 2m
        Copper films for applications in printed circuit boards usually have to be fine-grained to achieve even filling of microvias. When galvanically plating Cu films on roll-annealed Cu substrates, unacceptably large epitaxial crystals were found for certain conditions. Here galvanic Cu films were plated on oriented single-crystal Cu substrates from an additive-free electrolyte and from a commercial electrolyte designed for DC plating. The crystallite distribution in the films was mapped with XRD. For the additive-free bath, the transition to a polycrystalline film occurs more readily on ⟨111⟩ and ⟨100⟩ oriented surfaces, whereas films on ⟨110⟩ substrates are persistently epitaxial. A sequence of recursive twinning steps is the main mechanism for the transition to polycrystalline texture. The bath additives promote fine-grained films and they deliver, for the same plating conditions, remarkably improved results.
        Speaker: Ralf Bruening (Mount Allison University)
      • 7:10 PM
        Peak Intensity and Energy Confinement Enhancement of Airy Bullets 2m
        Over the last few years, Airy beams have attracted an increasing interest due to their peculiar characteristics, such as accelerating propagation trajectories featuring non-dispersion along with self-healing properties. Beside their relevance for fundamental optics research, these beams have found numerous applications in several fields including, among others, the generation of curved plasma channels and optical trapping. An Airy beam propagates following a curved trajectory without diffracting along one or two spatial dimensions. Similarly, an optical pulse featured by an Airy temporal profile is not affected by dispersion during its propagation (i.e. its temporal shape remains unchanged). Thus, by combining such confinements both in time and space, it is possible to generate a 3D-confined accelerating optical beam, which does not diffract/disperse along any coordinate, named Airy Bullet (AB). Herein, we present a numerical study of these AB dynamics, providing a technique capable of optimizing the power features associated to the spatio-temporal confinement of such a bullet. In particular, we show that by reshaping the initial spatio-temporal spectrum of the AB in order to obtain a maximal overlap with the spectral content associated with the main lobe, one is able to readily contain the spatio-temporal expansion of such a bullet.
        Speaker: domenico bongiovanni (INRS)
      • 7:12 PM
        Entangled photon pair source towards quantum spectroscopy 2m
        In nonlinear spectroscopy, measuring weak nonlinear signals generated from feeble signal and probe fields in a nonlinear material can be quite difficult, especially with photosensitive materials. The field of quantum spectroscopy has long theorised applications of photon pairs from Spontaneous Parametric Down-Conversion sources for enhancing two-photon nonlinear spectroscopy through the utilization of quantum properties. Using the high frequency correlations between photons in a pair as well as the tight pair creation times, it has been shown that two-photon frequency conversion processes such as two-photon absorption and sum-frequency generation are linear in input flux rather than quadratic, as with classical laser light. Building off of the established experimental foundation of entangled two-photon absorption and entangled photon pair up-conversion, I present a source of entangled photon pairs based off of periodically-poled magnesium oxide-doped lithium niobate capable of single-photon-level frequency conversion. This source is optimized for high photon fluxes and low chromatic dispersion which can be verified through sum-frequency generation in an identical, second crystal. This is a first step towards demonstrating time-domain quantum spectroscopy in biological media.
        Speaker: Mrs Aimee Gunther (Institute for Quantum Computing, University of Waterloo)
      • 7:14 PM
        3D Printed Hollow-Core Terahertz Optical Waveguides With Hyperuniform Disordered Dielectric Reflectors 2m
        Novel hollow-core THz waveguides featuring hyperuniform disordered reflectors are proposed, fabricated, and characterized. Our main motivation is to explore the possibility of designing hollow core waveguides that feature spectrally broad bandgaps that are potentially superior to those attainable with purely periodic structures. Particularly, we demonstrated theoretically that using resin/air material combination that offers relatively low refractive index contrast of 1.67/1, one can design a hollow core waveguide featuring a 90GHz (~21%) bandgap centered at 0.43THz. In such a waveguide, a highly porous PBG reflector comprised ~113μm radius cylinders connected with ~35μm thick bridges. We then attempted fabrication of such waveguides using 3D stereolithography. The diameter of the resultant waveguides (reflector size) is ~20mm, while the diameter of the hollow core is ~5mm. Due to limitations of 3D printer used in our work, the resolution was limited to 100µm which allowed us to print structures with bridges thicker than 200µm. As we demonstrated both theoretically and experimentally, thicker bridges lead to the overall reduction in the bandgap spectral size. Nevertheless, the fabricated waveguides featured relative wide bandgaps (up to ~15%), and low transmission losses (<0.10cm-1) within their PBGs.
        Speaker: Mr Tian Ma (Ecole Polytechnique de Montreal)
      • 7:16 PM
        Lasing in the nitrogen molecular ion 2m

        Lasing in the nitrogen molecular ion
        Mathew Britton, Patrick Laferriere, Ladan Arissian, Michael Spanner and P. B. Corkum
        Joint Attosecond Science Laboratory, National Research Council and University of Ottawa, Ottawa, Canada

        Intense light-matter interaction beyond a unimolecular limit faces unique challenges. In this regime, light and matter both have a non-negligible effect on each other. It is in this complex environment that lasing has been discovered on a nitrogen molecular ion transition [1].
        We investigate the gain dynamics in nitrogen ions created from a neutral gas by an intense ultrashort laser pulse. To isolate the phenomenon, we use a one atmosphere pure-nitrogen 200 µm thick gas jet in a vacuum chamber. The gain is initiated by an 800 nm pump pulse with intensity in the range of 2-4 x10^14 W/cm^2 and pulse duration of 27 fs. A weak second harmonic probe pulse monitors the time dependence of the gain on the B (v=0) to X (v=0) transition.
        We observe a peak gain of approximately 2 over a distance of about 200 µm and we measure gain as a function of nitrogen concentration, density, and intensity of the pump and probe. While the gain is present immediately (i.e. within the duration of the 27 femtosecond pump pulse) we observe two time-scales of decay: population inversion decay and rotational wave packet decay.

        [1] see for example, G. Point, Y. Liu, Y. Brelet, S. Mitryukovskiy, P. Ding, A. Houard, and A. Mysyrowicz, “Lasing of ambient air with microjoule pulse energy pumped by a multi-terawatt infrared femtosecond laser”, OPTICS LETTERS, 29, 1725, (2014)

        Speakers: Mathew Britton (Joint Attosecond Science Laboratory, National Research Council and University of Ottawa, Ottawa, Canada), Patrick Laferriere (Joint Attosecond Science Laboratory, National Research Council and University of Ottawa, Ottawa, Canada)
      • 7:18 PM
        Experiment friendly entanglement witness for multipartite entanglement in atomic frequency combs 2m

        Atomic frequency comb, an atomic ensemble with comb shaped optical transition, is useful for multimode photonic quantum memory where a photon is absorbed collectively over the teeth of the comb resulting in a multipartite entangled state. The teeth of the comb constitute the individual subsystems participating in the entanglement. Since each tooth of the comb consists of a macroscopic number of atoms (typically several thousand), the atomic frequency comb (AFC) system presents an entirely different class of entangled state, which we call the colossal entangled state, i.e., multipartite entanglement between macroscopic systems.

        In this work we propose an experimentally realizable witness and entanglement measure for the colossal entanglement in the AFC systems which is the entanglement between the teeth of the AFC. The witness is achieved in two steps. First we determine the minimum number of teeth coherently absorbing the photon, i.e., the coherence depth, from the signal to noise ratio of the light coming out of the AFC system. We argue that coherence depth is synonymous to entanglement depth, i.e., the minimum number of provably entangled systems, for the case when exactly one photon is present in the system. However, higher photon number component in the photonic states can cause differences between the coherence depth and the entanglement depth. We rectify this problem by estimating the probabilities P0 of no photon and P1 of having exactly one photon in the AFC system and using the bound on P1 for a given P0 and entanglement depth derived in [Hass et al. 2014]. Our method requires no prior knowledge of the number of teeth and is scalable. Furthermore, the method uses only macroscopic quantities to estimate the entanglement in the system, hence, is a suitable choice for the experimental demonstration of genuine multipartite entanglement. We have numerical and experimental results to support our entanglement witness.

        Speaker: Parisa Zarkeshian (University of Calgary)
      • 7:20 PM
        Field synthesis at 1.8 microns for isolated attosecond pulses 2m

        Attaining an isolated attosecond pulse via high harmonic generation requires a temporal gate that can act within one half cycle of the driving field. Here, we use the interplay of nonlinear optics and spatio-temporal coupling to synthesize a half-cycle pulse. The half cycle pulse is centered at 1.8 microns, the idler of an optical parametric amplifier, and is intense enough to generate isolated attosecond pulses, tuneable over an octave in the extreme ultraviolet. I will also discuss this tool to study attosecond dynamics in the condensed phase.

        Speaker: TJ Hammond (University of Ottawa/NRC)
      • 7:22 PM
        Anomalous magnetic moment (AMM) effect on some $2s^2 2p$ $^2P_{3/2}$ lifetimes 2m

        An experimental lifetime of exceptional accuracy [9.573(4)(5) (stat)(sys)] has been reported by Lapierre et al. [1] for the $2p$ $^2P_{3/2}$ state of Ar$^{13+}$. This result is in good agreement with theory [2] when neglecting the effect of the anomalous magnetic moment (AMM), namely 9.582(2) ms, whereas the lifetime with the AMM correction is 9.538(2) ms, well outside the experimental error bar.

        The theory method used by Tupisyn et al. started with the non-relativistic operator for the line strength of the $2p$ $^2P_{1/2}$ - $^2P_{3/2}$ transition and applied relativistic perturbation theory to the calculation of the lifetime as the inverse of the transition probability between these two fine-structure levels.

        The General Relativistic Atomic Structure Package (GRASP2K) [3] is different. It relies on a variational method for determining wave functions for the initial and final states and then a matrix element for a transition operator which, in the Gordon form, can determine the lifetime both with and without the AMM correction, using the observed transition energy. Our lifetimes, 9.5804(16) ms and 9.536(16) ms, respectively are in excellent agreement with the Tupystin et al. values. In GRASP2K calculations, a check on the accuracy of the wave function is the prediction of the transition energy and this is the basis for our error estimate. Thus the discrepancy with experiment for Ar$^{13+}$ remains unresolved.

        Data will be presented for other ions of the isoelectronic sequence. For K$^{14+}$ a measured value [4] is closer to the value with the AMM correction but the uncertainty in the experimental lifetime is so large that it includes both values.

        REFERENCES

        [1] A. Lapierre et al., Phys, Rev. Letters, 95, 183001 (2005)

        [2] I.I. Tupitsyn et al., Phys. Rev. A, 72, 062503 (2005)

        [3] P. Jonsson et al., Comp. Phys. Commun., 184, 2197 (2013)

        [4] E. Trabert et al., Phys. REv. A, **64"", 034501 (2001)

        Speaker: Charlotte Froese Fischer (NIST)
      • 7:24 PM
        Achieving super-resolution through nonlinear structured illumination 2m

        Conventional imaging systems are limited in their optical resolution by diffraction. Thus, super-resolution techniques are required to overcome this limit. Many super-resolution techniques, such as structured illumination (SIM) [1,2], have been developed. However, these techniques often take advantage of linear optical processes and only a few techniques applicable to nonlinear optical processes exist [3, 4]. Here, we propose a scheme similar traditional SIM compatible with coherent nonlinear processes such as second- and third-harmonic generation and predict a resolution improvement of up to ~4 fold.

        In traditional SIM the resolution is doubled by capturing and utilizing spatial frequencies that would otherwise not be received by the imaging system [1]. This may be further enhanced if the saturable absorption of the fluorescent molecules can be utilized to collect even higher harmonics of the spatial frequencies [5]. Since coherent imaging systems are linear with respect to the electric field, the concepts of structured illumination may be generalized to nonlinear widefield microscopy modalities where field amplitudes instead of field intensities are measured [6]. We show that this is possible through the use of second-harmonic and third-harmonic widefield microscopy and show a resolution improvement of three- and four-fold, respectively. Our results suggest that a spatial resolution smaller than 100 nm may be achievable.

        References:

        1. M.G.L Gustafsson. Journal of microscopy 198, 82-87 (2000).
        2. E. Betzig et al. Science 313, 1642-1645 (2006).
        3. C. Heinrich et al. Applied physics letters. 84, 816-818 (2004).
        4. K.M Hajek et al. Optics express 18, 19263-19272 (2010).
        5. M.G.L Gustafsson. Proceedings of the National Academy of Sciences of the United States of America 102, 13081-13086 (2005).
        6. O. Masihzadeh et al. Optics express 18, 9840-9851 (2010).
        Speaker: Aazad Abbas (University of Ottawa - Quantum Photonics Group)
      • 7:26 PM
        Hyperbolic Metamaterial Nano-Resonators Make Poor Single Photon Sources 2m

        We study field and radiation attributes of photonic nano-resonators composed of alternating metal and dielectric layers, known as hyperbolic metamaterials (HMMs). HMMs offer the ability to confine light in ultra-small volumes and enhance its interaction with matter, thereby increasing the spontaneous emission rates of nearby photon emitters through the Purcell effect. It has been suggested that one of the first applications of HMM nanophotonics is in the domain of single photon sources for use in quantum cryptography and quantum plasmonics. Here we describe the physics of HMM nano-resonators in terms of open cavity resonant modes known as quasinormal modes (QNMs). Using an analytical expansion of the photon Green function in terms of QNMs, we introduce a modelling technique that is orders of magnitude faster that direct dipole solutions of Maxwell's equations and offers considerable insight into the HMM coupling effects. We show how coupling to HMM nano-resonators can substantially increase spontaneous emission rates of quantum emitters by an order of magnitude more than pure metal resonators. However, in contrast to recent claims, we also show that most of this emission increase is lost to Ohmic heating. We demonstrate that, counter-intuitively, less metal present in the HMM resonator results in larger non-radiative losses. Using our semi-analytical QNM theory, we describe how this increase in photon quenching originates from an increased overlap between the metal and dielectric, which allows fields to leak or tunnel into the lossy metallic regions. We thus conclude that HMM nano-resonators likely make poor single photon sources, and that pure metallic resonators are preferred for single photon applications.

        Speaker: Simon Axelrod (Queen's University)
      • 7:28 PM
        Generation of vortex beam superpositions using angular gratings 2m

        Vortex beams form a class of beams carrying orbital angular momentum (OAM). A single photon carries OAM where l represents the OAM state and a beam with non-zero OAM state has a zero intensity at its centre and a helical phase wavefront.

        Vortex beams have gained interest for their applications in optical manipulation, optical communication and quantum information [1-3]. In particular, they can enhance communication security by improving the quantum key distribution (QKD) procedure [4]. The original proposal uses the photon polarization degree of freedom, resulting in each photon carrying a single bit. Since OAM states are unbounded and mutually orthogonal, using instead the OAM degree of freedom as a basis enables far greater channel capacity. As QKD requires superpositions of states, this improved version of QKD requires superpositions of different OAM values.

        There are many ways to generate vortex beams with bulk optics, such as spiral phase plates, spatial light modulators, q-plates and cylindrical lens mode converters [5-8]. However, an integrated photonic approach has advantages over bulk optics because of its scalability, stability and small size. It turns out that ring resonators with lateral grating elements, called angular gratings, radiates a vortex above the structure when on resonance [9,10]. To generate a superposition of vortex beams, we expand this idea to a single ring with two sets of gratings, one on the inside wall and one on the outside. We then show with simulations that, after post-selecting on one of the circular polarizations, we can generate OAM superposition states based on the number of grating elements for each grating.

        1. J. E. Curtis, D. G. Grier Phys. Rev. Lett. 90, 133901 (2003).
        2. G. Gibson et al. Optics Express 12, 5448-5456 (2004).
        3. R. W. Boyd et al. Proc. Of SPIE, 7948, 79480L (2011).
        4. A. Mair et al. Nature 412, 313-316 (2001).
        5. M. W. Beijersbergen et al. Opt. Commun. 112, 321 (1994).
        6. V. Y. Bazhenov et al. J. Mod. Opt. 39, 985 (1992).
        7. L. Marrucci et al. Phys. Rev. Lett. 96, 163905 (2006).
        8. L. Allen et al. Phys. Rev. A 45, 8185 (1992)
        9. Y. F. Yu et al. Optics Express 18, 21651-21662 (2010).
        10. X. Cai et al. Science 338, 363-366 (2012).
        Speaker: Ms Marie-Claude Dicaire (University of Ottawa)
    • 7:00 PM 10:00 PM
      DASP Poster Session with beer / Session d'affiches avec bière DPAE SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: Prof. Richard Marchand (University of Alberta)
      • 7:02 PM
        Miniature Plasma Imager: A new tool for in situ ionospheric and auroral investigations from nanosatellites 2m
        Development has commenced at the University of Calgary on a prototype next-generation ion imager called the Miniature Plasma Imager (MPI). The work is being performed under contract to the Canadian Space Agency as part of its Space Technology Development Program. The Miniature Plasma Imager is designed to be an smaller Thermal Ion Imager, which is the sensor used on the Swarm Electric Field Instrument to measure ion drift and temperature in the F region ionosphere. Having similar ion focusing optics, MPI replaces the high-voltage (5 kV to 8 kV) TII electro-optical detector with an ion-sensing IonCCD(TM) running at 24 V. We present an overview of the new instrument, describe its anticipated measurement performance (velocity resolution and accuracy), and discuss its application to multi-point ionospheric and auroral physics studies using nanosatellite (<10 kg) orbital platforms.
        Speaker: Johnathan Burchill (University of Calgary)
    • 7:00 PM 10:00 PM
      DCMMP Poster Session with beer / Session d'affiches, avec bière DPMCM SITE Atrium

      SITE Atrium

      University of Ottawa

      Convener: Giovanni Fanchini (The University of Western Ontario)
      • 7:00 PM
        Structure and Dynamics with Ultrafast Electron Microscopes: Watching nano-microstructural evolution during complex crystallization in a-Ge 2m
        The crystallization of amorphous semiconductors is a strongly exothermic process. Once initiated, the release of latent heat can be sufficient to drive a self-sustaining crystallization front through the material in a manner that has been described as explosive. Using Dynamic Transmission Electron Microscope (DTEM), we have obtained time-resolved snap shots of three distinct microstructural zones as they are formed following pulsed laser excitation. This allows the direct observation of a rich variety of physical processes occurring at nanosecond time scales, including nanocrystallite nucelation and grain growth, crystallization front faceting and self-diffusion at the interface as well as the onset of complex layered microstructure far from initially illuminated zone. This work reveals new insights into the mechanisms governing this complex crystallization process and provides a dramatic demonstration of the power of DETM for studying time-dependent material processes far from equilibrium.
        Speaker: Mark Stern (McGill University)
      • 7:02 PM
        Photoinduced phase transition in vanadium dioxide: visualizing the time-dependent crystal potential using ultrafast electron diffraction data 2m
        Vanadium dioxide is notable for exhibiting several low-temperature insulating phases and having a very well studied insulator-metal transition at ~68$^{\circ}C$ that is associated with a crystallographic change from monoclinic semiconductor to rutile metal. Using a combination of ultrafast electron diffraction (UED) and broadband spectroscopy, we have recently demonstrated that photoexcitation of monoclinic vanadium dioxide crystals below a threshold fluence induces a transition to a metastable state with monoclinic crystallography, but metal-like optical/electronic properties. This long-lived metallic phase appears to have no equilibrium analog. A detailed structural characterization of this phase, using a 3D visualization of electron scattering potential, is the subject of this poster. This visualization techniques confirms previous suspicions and offers more dynamical information than radial pair-correlation functions.
        Speaker: Laurent René de Cotret (McGill University)
      • 7:04 PM
        A Phononic Crystal Waveguide for Surface Acoustic Waves 2m
        Surface acoustic waves (SAWs) on semiconductors, such as gallium arsenide (GaAs), are able to control quantum processes. SAW devices are augmented with phononic crystal waveguides to have fine control of the acoustic path. A phononic crystal in a GaAs substrate is produced by wet etching a square lattice array of void inclusions with an L1 defect. GaAs by its piezoelectricity, is suited for SAW generation via interdigitated transducers (IDTs). Initially, an IDT design must allow for determination of the phononic crystal mode frequency which is difficult to predict exactly. IDTs with uniform adjacent electrode overlap produce a narrow SAW bandwidth, which is even narrower with additional electrodes. Such low bandwidth is not practical for probing the mode frequency since it is unlikely to coincide. However, adjacent electrode overlap and a large number of electrodes are necessary to achieve appreciable SAW amplitude on GaAs; hence an optimized IDT is necessary for sufficient bandwidth and amplitude. Apodized IDTs with varying electrode overlap are developed for large SAW bandwidth and amplitude to probe the waveguide mode frequency. Once the mode is determined, focusing, narrowband IDTs on GaAs are then utilized for high power excitation of the phononic crystal mode frequency. The SAW vertical displacement amplitude is measured with surface scanning Sagnac interferometry as the SAW interacts with the phononic crystal. Spatial and frequency mapping of the SAW vertical displacement amplitude is analyzed to determine transmission and modal qualities of the phononic crystal waveguide.
        Speaker: Mr Edward Muzar (Queen's University)
      • 7:06 PM
        Phonon Dynamics of Lead Scandium Tantalate 2m
        Brillouin light scattering experiments were performed on lead scandium tantalate ceramics using a 180˚ backscattering geometry. Spectral peaks due to longitudinal bulk acoustic modes were observed and their frequencies were used to determine the corresponding phonon velocities and elastic constant c¬11. Temperature dependence of longitudinal bulk mode frequencies, and subsequently velocities, was characterized in the high temperature regime. Experiments performed on a sample of lead scandium tantalate ceramic coated with a thin film of aluminium failed to yield Brillouin peaks due to surface acoustic modes. Complementary Raman scattering experiments were performed on lead scandium tantalate at room temperature and high temperatures.
        Speaker: Mr Stephen Spencer (Memorial University of Newfoundland)
      • 7:08 PM
        Monte Carlo studies of the pseudogap regime in the cuprate superconductors 2m
        We present a theory that describes the pseudogap regime of the hole-doped cuprate superconductors by incorporating the competing effects of superconducting and charge density wave orders into six-dimensional degrees of freedom on a two-dimensional lattice [Science 343, 1336 (2014)]. Using Monte Carlo simulations, we calculate the charge order correlations and diamagnetic susceptibility [PRB 90, 094515 (2014)] associated with this O(6) model. We demonstrate that the structure factors calculated using our theory agree qualitatively with recent X-ray scattering experiments on hole-doped YBa$_2$Cu$_3$O$_{6+x}$ for a wide range of temperatures about the superconducting transition. We also study the effects of incorporating into our model interlayer coupling and disorder [PRB 92, 174505 (2015)]. In the presence of disorder, we find that our theory can reproduce experimental structure factors in the zero temperature limit.
        Speaker: Lauren Hayward Sierens (University of Waterloo)
      • 7:12 PM
        Intrinsic instability of metal-trihalide perovskite solar cell 2m
        Metal-trihalide perovskite is a new promising third generation active material for solar cell applications. The material is crystallized in a perovskite structure ABX3, where A is an organic cation (e.g. formamidinium), B is the metal cation (lead) and X is the halide anion (iodine). Perovskites exhibit the power conversion efficiency, which is comparable to silicon photovoltaic devices. Perovskite material can be synthesized using low-temperature and low-cost method, combined with the ability to be made flexible, tunable band gap, broad range of absorption spectrum, and high carrier mobility required for solar cells. Although the properties are promising, there are challenges to overcome before perovskite solar cells can be viewed as a competitor to silicon technology. It is commonly assumed that the reaction with water or oxygen in the external environment leads to a poor stability of hybrid halide materials. Its instability appears like a spontaneous phase separation into the formamidinium iodide and lead(II) iodide. Here, we aim to use first-principles calculations to capture energies of the material degradation. Our calculations suggest that the decomposition is exothermic, independent of the water or oxygen in the external environment. It means that the poor chemical stability is intrinsic to metal-trihalide perovskite structure. Now we are working on understanding of the instability mechanism in virtue of electrostatic potential energy of the metal-trihalide perovskite structure. The result will guide the search for materials with improved stability.
        Speaker: Mr Chao Zheng (McMaster University)
      • 7:14 PM
        Electron Localization in Group III-V Semiconductor Compound Alloys 2m
        We explore the band structures of new III-V material zinc blende alloys composed of B, N, Ga, As, In, Sb, and Bi for 1.55 μm wavelength telecommunication lasers and their corresponding electron localization at atomic sites from first principles. Engineering III-V semiconductors by mixing modifies their electronic properties including band gaps and lattice constants that are typically a blend of the original compounds and elements. Isoelectronic elements often result in undesirable effects. Electron localization in the vicinity of band edges affects the efficiency of carrier transport and recombination in lasers and solar cells. A new method has been developed to determine the electron localization from muffin tin radii (atomic sites) using the scheme of outlier detection with quartiles of electron probabilities. The advantage of this method is the ability to distinguish a strongly localized electron within the atomic muffin tin radius from a baseline of delocalized electrons. Comparing the results with the unfolded band structures’ Bloch character; the outlier method is in general agreement. The industry standard of InGaAs for 1.55 μm is shown to have the least amount of localized electronic states near the band edges. Alternatively, we find that the electron localization is increased, noticeably with the addition of B and Bi, which affects both radiative and non-radiative recombination rates. To accommodate future Group III-V semiconductor band engineering, we suggest design criteria to facilitate the prediction of localization in new alloys.
        Speaker: Christopher Pashartis (McMaster)
      • 7:16 PM
        Real-space renormalization group approach to the Anderson model 2m
        Real-space renormalization group approach to the Anderson model Many of the most interesting electronic behaviors currently being studied are associated with strong correlations. In addition, many of these materials are disordered either intrinsically or due to doping. Solving interacting systems exactly is extremely computationally expensive, and moreover approximate techniques developed for strongly correlated systems do not adapt to the inclusion of disorder easily. However a real-space renormalization group (RSRG) approach seems ideally suited for strongly disordered systems. While this approach has been successfully applied to many systems, few applications have been specific to the Anderson model. We present a RSRG study of the Anderson model, benchmarking density of states and inverse participation ratio results against exact diagonalization. Our approach points to the possibility of a RSRG approach to strongly disordered and interacting systems of significantly greater size than currently possible with exact diagonalization
        Speaker: Eamonn Campbell (Trent University)
      • 7:18 PM
        Is SmB6 the topological insulator or not ? 2m
        We theoretically examined whether samarium hexaboride (SmB$_6$) is topological insulator, or not. Despite the fact that the SmB$_6$ has long been known as a topological Kondo insulator, with strong correlations and band hybridization, it is still of a great interest because of low-temperature transport anomalies which have recently been interpreted as evidence that SmB$_6 $ is a topological insulator. SmB$_6 $ behaves electronically at high temperatures like an insulator, and at low temperature its resistance mysteriously saturates. We studies de Haas van-Alphen quantum oscillation results to resolve the Fermi surface topology in this material. Although dHvA measurement may be consistent with two-dimensional conducting electronic states, we find an elongated 3D ellipsoidal Fermi surface . Furthermore, resistance measurement also can give some evidence of SmB$_6$ topological surface states, by study different geometries to determine whether the conduction is dominated by the surface or the bulk. Another measurement is Scanning Tunneling Microscopy (STM) which use to discover the properties of the surface states with atomic spatial resolution.Finally, Angle-resolved photo-emission spectroscopy (ARPES), is another useful surface state probe directly the electronic structure of the (SmB$_6$).
        Speaker: Mrs Khawla Elfied (Memorial University of Newfoundland)
      • 7:20 PM
        Indirect internuclear coupling in topological insulator Bi2Se3 2m
        Topological insulators constitute a new class of material with an energy gap in the bulk and unusual metallic states on the surface. To date, most experiments have focused on probing the surface properties of these materials and suppressing the often inevitable contribution from bulk states. However, the bulk states in topological materials are of interest on their own and contain useful information that can be extracted with a local probe like nuclear magnetic resonance (NMR). Recently, 77Se NMR experiments on Bi2Se3 single crystals have reported unusual field-independent linewidths and short spin-echo decays [1]. It is likely that an unexpectedly strong indirect internuclear coupling, characteristic of inverted band structures in topological materials, is the probable cause of these peculiar results. The main objective of our research project is to provide a theory that explains the experiment of Ref. [1]. Starting from a microscopic tight-binding model for Bi2Se3, we calculate the Ruderman-Kittel-Kasuya-Yoshida (RKKY) and Bloembergen-Rowland (BR) couplings between nuclear spins, as well as the T1 relaxation time. We will compare our results to the experimentally available data. [1] N. Georgieva, D. Rybicki, R. Guhne, G. Williams, S. Chong, I. Garate and J. Haase (arXiv: 1511.01727; manuscript submitted).
        Speaker: Chloé Gauvin-Ndiaye (Université de Sherbrooke)
      • 7:22 PM
        Can gravity stabilize a topological quantum memory at finite temperature? 2m
        We study the existence of stable topological quantum memory at finite temperature. This aids in tackling the fundamental problematic of storing quantum information for macroscopically significant times without the use of external intervention in the form of error correction. It has been argued before that a gravitational attraction could confine the anyonic excitations in a topological material, thus preventing them from altering the topological information stored in the system. This idea has led Hamma et al. (2009) to propose a model in which the toric code qubits are coupled to a bosonic bath materializing the gravitational force. Although this confinement is well established for ordinary matter, it has not been observed before for Z2-type excitations, i.e., particles whose mass is preserved only modulo 2. We study this question using numerical simulations wich are performed on a continuous lattice in which the thermal processes were limited to creation, annihilation, and diffusion, with the latter being constrained by an additional energy cost. While preliminary data does not indicate the presence of a defect density threshold in the topological phase below which open strings are confined and the topological order remains intact, our results do not dismiss its existence conclusively and warrant further inquiry.
        Speaker: Thomas Gobeil (University of Sherbrooke)
      • 7:24 PM
        Quantum Model for Machine Learning Applications 2m
        The field of machine learning has been revolutionized by the recent improvements in the training of deep networks. Their architecture is based on a set of stacked layers of simpler modules. One of the most successful building blocks, known as a restricted Boltzmann machine, is an energetic model based on the classical Ising Hamiltonian. In our work, we investigate the bene