For many years physicists divided the world of quantum particles into two kingdoms – bosons and fermions. Anyons are particles with a sort of memory, that fall outside those kingdoms. In recent decades theorists have produced an enormous literature about the possible occurrence and properties of anyons. It is only in the last few months, however, that clear experimental confirmation has...
The current and upcoming astroparticle physics program will help understand the nature of the universe with the possible discovery of the nature of dark matter. The efforts towards greater sensitivities to the small signal induced by the very rare event direct dark matter experiments aim to detect turn into a continuous fight against radioactive background. There are various methods to reduce...
Recently, Kitaev materials have attracted great interest due to their potential to realize a quantum spin liquid ground state which hosts gapless Majorana excitations. In this talk, after a review of the physics of Kitaev materials, I will discuss the effects of static magnetic and electric fields on Kitaev's honeycomb model. Using the electric polarization operator appropriate for Kitaev...
Many of previous approaches for the firewall puzzle rely on a hypothesis that interior partner modes are embedded on the early radiation of a maximally entangled black hole. Quantum information theory, however, casts doubt on this folklore and suggests a different tale; the outgoing Hawking mode will be decoupled from the early radiation once an infalling observer, with finite positive energy,...
The Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei (GRIFFIN), is a state-of-the-art spectrometer designed for the $\beta$-decay studies of exotic nuclei produced at the TRIUMF-ISAC facility. It provides unique research opportunities in the fields of nuclear structure, nuclear astrophysics, and fundamental interactions.
The spectrometer is composed of an array of 16...
I will show and discuss the recent progress of spectroscopic studies of neutron-rich nuclei near and beyond the neutron drip line, using the large acceptance multi-purpose spectrometer SAMURAI at RIBF at RIKEN [1]. After a brief introduction on characteristic features of structures near and beyond the neutron dripline, we focus on the recent experimental results on the observation of 25-28O...
Cooling atomic gases to ultracold temperatures revolutionized the field of atomic physics, connecting with and impacting many other areas in physics. Recent advances in producing ultracold molecules suggest similarly dramatic discoveries are on the horizon. I will review the physics of ultracold molecules, including our work bringing a new class of molecules to ultracold temperatures....
Accelerator Science is both a discipline in its own right within modern physics and provides highly powerful tools for discovery and innovation in many other fields of scientific research. Accelerators do support different disciplines of subatomic physics, material sciences, life sciences and applications in research and industry. Accelerator Science Community does perform R&D to improve...
One of the cornerstones of Quantum Mechanics (QM), Heisenberg’s Uncertainty Principle (HUP), establishes that it is not possible to simultaneously measure with arbitrary precision both the position and the momentum of a quantum system. This principle, however, does not prevent one from measuring with infinite precision the system’s position. However, theories of Quantum Gravity, aiming to...
Over the past decade, significant progress has been made in the commercialization of quantum sensors based on ultra-cold atoms and matter-wave interferometry. Nowadays, the first absolute quantum gravimeters have reached the market and there is even a cold-atom machine on the International Space Station. Matter-wave interferometers utilize the wave nature of atoms and their interaction with...
Superconducting radiofrequency (SRF) cavities have been used for more than 50 years to increase the energy of charged particles. In Canada there are two accelerator centres which use SRF technology, i.e TRIUMF and the Canadian Light Source (CLS). The CLS was the first light source to use an SRF cavity in a storage ring from the beginning of operations in 2004. TRIUMF began developing SRF...
I will discuss muon spin rotation (muSR), nuclear magnetic resonance (NMR) and thermodynamic measurements on several Mo3O8-based cluster Mott insulators consisting of a 1/6th-filled breathing Kagome lattice. Depending on sometimes subtle structural differences between these various materials, a number of different magnetic phases can be stabilized, including possible quantum spin liquids: a...
One of the most famous tidbits of received wisdom about quantum mechanics is that “you can’t ask” which path a photon took in an interferometer once it reaches the screen, or in general, that only questions about the specific things you finally measure are well-posed at all. Much work over the past decades has aimed to chip away at this blanket renunciation, and investigate “quantum...
Scalar-tensor gravity can be described as general relativity plus an effective imperfect fluid corresponding to the scalar field degree of freedom of this class of theories. A symmetry of electrovacuum Brans-Dicke gravity translates into a symmetry of the corresponding effective fluid. We present the formalism and an application to an anomaly in the limit of Brans-Dicke theory to Einstein...
We study Quantum Gravity effects on the density of states in statistical mechanics and its implications for the critical temperature of a Bose Einstein Condensate and fraction of bosons in its ground state. We also study the effects of compact extra dimensions on the critical temperature and the fraction. We consider both neutral and charged bosons in the study and show that the effects may...
Launched in 2016, our four-year Integrated Science program is intended for students who have a passion for science and who wish to dissolve the barriers between the traditional scientific disciplines. The highlight of the program is a second-semester, first-year “megacourse” that takes a radical approach to first-year science by asking four overarching questions: How did Earth evolve, what is...
The CLS2 is a concept design of a next generation synchrotron light source to keep Canada at the forefront of scientific research that is uniquely available to researchers with access to such national infrastructure. Canada's research priorities in health and medicine, agriculture and food security, advance materials and industrial research, will all be enabled with national access to a next...
We investigate the effect of coupling between translational and internal degrees of freedom of composite quantum particles on their localization in a random potential. We show that entanglement between the two degrees of freedom weakens localization due to the upper bound imposed on the inverse participation ratio by purity of a quantum state. We perform numerical calculations for a...
Loop Quantum Gravity (LQG) is one proposed approach to quantize General Relativity. In previous literature LQG effects have been applied to Bianchi II spaces and here we numerically solve the resulting equations of motion using the fixed step 6th order Butcher-1 Runge-Kutta method. We also test, for a wide range of initial conditions, analytic transition rules for the Kasner exponents and...
Guided by the application of loop quantum gravity (LQG) to cosmological space-times and techniques developed therein, I will present an effective framework for vacuum spherically symmetric space-times. Stationary solutions of the effective theory give an LQG corrected metric with a number of interesting properties including curvature scalars that are bounded by the Planck scale and a minimal...
Hollow-core optical fibres provide μm-scale confinement of photons and atoms and reduce the power requirements for optical nonlinearities. This platform has opened tantalizing possibilities to study and engineer light-matter interactions in atomic ensembles. However, the purity, efficiency and nature of these interactions are contingent on the number, geometry and movement of atoms within the...
Using Loop Quantum Gravity corrections one can study quantum gravity effects for a dust-gravity system, resulting in a Loop Quantum version of Oppenheimer-Snyder collapse. In this talk I will explain how this model is built up and the consequences of adding holonomy corrections to the classical theory. In particular, we see that, in the black hole formation, there is a bounce when the energy...
We model an atomic Bose-Einstein condensate (BEC) near an instability, looking for universal features. Instabilities are often associated with bifurcations where the classical field theory provided here by the Gross-Pitaevskii equation predicts that two or more solutions appear or disappear. Simple examples of such a situation can be realized in a BEC in a double well potential or in a BEC...
Understanding the structure of complex many-body nuclei is one of the central challenges in nuclear physics. The conventional shell model is capable of explaining the structure of stable nuclei, but it starts to shatter towards the driplines or rare isotopes. To explain the new trends in the shell model at the driplines, it is essential to study these exotic nuclei. Halo nuclei are prime...
At TRIUMF, Canada’s particle accelerator centre, the TIGRESS Integrated Plunger (TIP) and its configurable detector systems have been used for charged-particle tagging and light-ion identification in Doppler-shift lifetime measurements using gamma-ray spectroscopy with the TIGRESS array of HPGe detectors. An experiment using these devices to measure the lifetime of the first $2^+$ state of...
The Canadian scientific community lost their local source of neutron beams for materials research on March 31st 2018, due to the closure of the National Research Universal reactor at Chalk River National Laboratories. Furthermore, the dwindling global supply of neutrons has made it increasingly difficult for local scientists to access neutron beams. There is a growing demand for the...
The NEWS-G collaboration aims to detect sub-GeV WIMPs using Spherical Proportional Counters (SPC). During the past 6 years, the collaboration developed a new 140 cm diameter detector. This detector - larger than the previous generation - is made from stringently selected materials for their radio-purity and is enclosed in a spherical shielding made of different layers of polyethylene and low...
Lieb-Robinson and related bounds set an upper limit on the speed at which information propagates in non-relativistic quantum systems. Experimentally, light-cone-like spreading has been observed for correlations in the Bose-Hubbard model (BHM) after a quantum quench. Using a two-particle irreducible (2PI) strong-coupling approach to out-of-equilibrium dynamics in the BHM we calculate both the...
In recent years, multi-species trapped-ion systems have been investigated for the benefits they provide in quantum information processing experiments, such as sympathetic cooling and combining long coherence time of one species with ease of optical manipulation of the other. However, a large mass-imbalance between the ions result in decoupling of their motion in the collective vibrational...
Neutron rich Mg isotopes far from stability belong to the island of inversion, a region where the single particle energy state description of the shell model breaks down and the predicted configuration of nuclear states becomes inverted. Nuclei in this region also exhibit collective behaviour in which multiple particle transitions and interactions play a significant role in the...
DEAP-3600 is a direct dark matter search experiment located 2km underground at SNOLAB. The experiment is located at this depth to shield the sensitive detector from cosmic rays. The experiment uses a liquid argon target to search for WIMP dark matter candidates. Liquid argon is chosen as a target material for three reasons: it has a good scintillation light yield, it is transparent to its own...
The Electron Cyclotron Resonance Ion Source is a versatile and reliable source to charge-breed rare isotopes at the TRIUMF's Isotopes Separation and Acceleration (ISAC) facility. Significant research work has been done by different groups worldwide to improve the efficiency and performance of the ECRIS as a charge state booster. The most recent of these research works is the implementation of...
Neutron beta decay is a fundamental nuclear process that provides a means to perform precision measurements that test the limits of our present understanding of the weak interaction described by the Standard Model of particle physics and puts constraints on physics beyond the Standard Model. The Nab experiment will measure a, the electron-neutrino angular correlation parameter and b, the Fierz...
The TRIUMF Ultra-Cold Advanced Neutron (TUCAN) collaboration is currently building a next-generation ultra-cold neutron source, with a neutron electric dipole moment (nEDM) measurement as the flagship experiment. The nEDM measurement is based on the Ramsey method of separated oscillating fields to measure the precession frequency of the neutron in combined magnetic and electric fields. The...
If one wishes to understand and successfully simulate the radiation damage of biological tissue one needs to understand the fundamental ionization processes of molecules in the gas or vapour
phase first. The latter problem has been addressed in a number of studies in recent years, but experimental data have remained scarce and accurate cross-section predictions based on first-principles...
For 50 years, TRIUMF has stood at the frontier of scientific understanding as Canada’s particle accelerator centre. Driven by two made-in-Canada cutting edge accelerators - the world’s largest cyclotron, and our new high-power superconducting linear accelerator - we continue to ask the big questions about the origins of the universe and everything in it.
With over five decades of...
Isotopes of Heavy and Super Heavy nuclei are typically produced in fusion-evaporation reactions. In these types of reactions neighboring isotopes are often produced simultaneously. This makes it incredibly difficult to assign experimentally observed decay properties to specific isotopes. Presently, such assignments are heavily reliant on the use of excitation functions, cross-bombardment...
Many research efforts in physics rely on design, implementation, and execution of numerical studies. These studies are often the guiding torch of further experimental investigations, but they are rarely carried out with software development principles in mind. As a result, efficiency and verification measures are often not incorporated in the R&D process and this impairs the quality and...
Hyper-Kamiokande is the next generation water-Cherenkov neutrino experiment, building on the success of its predecessor Super-Kamiokande. To match the increased precision and reduced statistical errors of the new detectors, improvements to event reconstruction and event selection are required to suppress backgrounds and reduce systematic errors. Machine learning has the potential to provide...
Neutrons were applied in the study of medicine very quickly. A mere six years after discovery, neutrons were first used for cancer therapy. Interest in neutron radiotherapy waxed and waned over the following decades. The last use of neutron-only therapy, treating cancer of the salivary glands, ceased several years ago.
There is, however, still interest in boron neutron capture therapy (BNCT)...
In theories with extra dimensions, the standard QCD axion has excited states with higher mass. The axion of such theories, named the Kaluza-Klein (KK) axion, would have a significantly shorter decay time for higher mass states. This would allow for axion decays on Earth, even in the absence of a strong magnetic field. It would also mean that a fraction of heavier mass axions created in the Sun...
We study the response of a static Unruh-DeWitt detector outside an exotic compact object (ECO) with a variety of (partially) reflective boundary conditions in 3+1 dimensions. The horizonless ECO, whose boundary is extremely close to the would-be event horizon, acts as a black hole mimicker. We find that the response rate is notably distinct from the black hole case, even when the ECO...
Crowded soft-matter and biological systems organize locally into preferred motifs. Locally-organized motifs in soft systems can, paradoxically, arise from a drive to maximize overall system entropy. Entropy-driven local order has been directly confirmed in model, synthetic colloidal systems, however similar patterns of organization occur in crowded biological systems ranging from the contents...
We derive Loop Quantum Gravity corrections to the Raychaudhuri equation in the interior of a Schwarzschild black hole and near the classical singularity for several schemes of quantization. We show that the resulting effective equation implies defocusing of geodesics due to the appearance of repulsive terms. This prevents the formation of conjugate points, renders the singularity theorems...
An exciting frontier in quantum information science is the creation and manipulation of quantum systems that are built and controlled quanta by quanta. In this context, there is active research worldwide to achieve strong and coherent coupling between light and matter as the building block of complex quantum systems. Despite the range of physical behaviours accessible by these QED systems, the...
The symmetries of unconventional superconductors may be classified by the locations of their gap nodes. Recently, the role of spin-orbit coupling (SOC) has become important, as sufficiently strong SOC generates novel mixed-parity superconductivity. In this talk, I show that the nodal structure of unconventional superconductors may be determined by angle-dependent magneto-thermal conductivity...
A relativistic theory of gravity like general relativity produces phenomena differing fundamentally from Newton’s theory. An example, analogous to electromagnetic induction, is gravitomagnetism, or the dragging of inertial frames by mass-energy currents. These effects have recently been confirmed by classical observations. Here we show, for the first time, that they can be observed by a...
Continuous waves from non-axisymmetric neutron stars are orders of magnitude weaker than transient events from black hole and neutron star collisions. Unlike a transient event, a continuous wave source will allow repeated observations. We will present results of all-sky searches for neutron stars and other sources carried out by the Falcon pipeline and discuss interplay between detector...
The study of neutron rich nuclei far from the valley of stability has become an increasingly important field of research within nuclear physics. One of the decay mechanisms that opens when the decay Q value becomes sufficiently large is that of beta-delayed neutron emission. This decay mode is important when studying the astrophysical r-process as it can have a direct effect on theoretical...
DEAP-3600 is a direct detection dark matter experiment with single-phase liquid argon as the target material to search for nuclear recoil signal from the interaction of WIMPs, one of the most widely accepted hypotheses for dark matter. Along with the occurrence of this elastic interaction of WIMP and target nuclei, theories also predict the dark matter signal could vary over the course of a...
From its inception, the Life Sciences division at TRIUMF has leveraged the laboratory’s extensive particle accelerator expertise and infrastructure to develop novel technologies that help understand life at the molecular level. This includes novel technologies and research in particle beam therapy and biobetaNMR, but also prominently the production of short-lived (half-life <2 hr) positron...
A state-preserving quantum counting algorithm is used to obtain coefficients of a Lanczos recursion from a single ground state wavefunction on the quantum computer. This is used to compute the continued fraction representation of an interacting Green's function for use in condensed matter, particle physics, and other areas. The wavefunction does not need to be re-prepared at each iteration....
The study of plasmonics has the potential to reshape the physics of light-matter interactions in metallic nanohybrids and their applications to nanotechnology. Metallic nanohybrids are mode metallic nanoparticles and quantum emitters such as quantum dots. Recently, there is a considerable interest to study the light-matter interaction in the nanoscale size plasmonic nanohybrids. When an...
Our current understanding of the core-collapse supernova explosion mechanism is incomplete, with multiple viable models for how the initial shock wave might be energized enough to lead to a successful explosion. Detection of a gravitational wave (GW) signal emitted in the initial few seconds after core-collapse would provide unique and crucial insight into this process. With the Advanced LIGO...
Spontaneous two-photon decay rates for the $1s2s\;^1S_0$ -- $1s^2\;^1S_0$ transition in helium and its isoelectronic sequence up to $Z$ = 10 are calculated, including the effects of finite nuclear mass. We use correlated variational wave functions in Hylleraas coordinates and pseudostate summations for intermediate states. The accuracy of previous work is improved by several orders of...
In this talk, I will consider the stability of asymptotically anti-de Sitter gravitational solitons. These are globally stationary, asymptotically (globally) AdS spacetimes with positive energy but without horizons. I will introduce my ongoing project investigating solutions of the linear wave equation in this class of backgrounds. I will provide analytical expressions for the behavior of the...
The neutrino, a fundemental particle, offers the potential to image parts of the universe never before seen and can provide an early warning for cosmic events. With their ability to carry information across the universe unperturbed, neutrinos offer a clear image of the cosmos and can provide insight into its nature with relative ease. Learning from successful neutrino telescopes such as...
Since the temperature of an object that cools decreases as it relaxes to thermal equilibrium, naively a hot object should take longer to cool than a warm one. Yet, some 2300 years ago, Aristotle observed that “to cool hot water quickly, begin by putting it in the sun.” In the 1960s, this counterintuitive phenomenon was rediscovered as the statement that “hot water can freeze faster than cold...
The mass and spin properties of black hole binaries inferred from their gravitational-wave signatures reveal important clues about how these binaries form. For instance, stellar-mass black holes that evolved together from the same binary star will have spins that are preferentially aligned with their orbital angular momentum. Alternatively, if the black holes formed separately from each other...
Resonant laser ionization spectroscopy uses multiple lasers to step-wise excite atom, therefore is a powerful tool for the study of high energy atomic structures, such as Rydberg states and autoionizing states. At the laser ion source test stand (LIS-stand) in TRIUMF, resonant laser ionization spectroscopy is used to study complex atoms. The spectroscopy results not only provide efficient...
The Large Hadron Collider (LHC) at CERN supports a plethora of experiments aimed at improving our understanding of the universe by attempting to solve the many answered questions in physics, such as: What is the nature of dark matter? Why is electric charge quantized? Why do the free parameters of the Standard Model (SM) have their particular values? To-date, the SM has been stringently...
Molecular self-assembly is one of the most important bottom-up fabrication strategies to produce two-dimensional networks at solid surfaces. The formation of complex two-dimensional (2-d) surface structures at the molecular scale relies on the self-assembly of functional organic molecules on solid substrates. Driven by an intricate equilibrium between molecule–molecule and molecule–substrate...
The understanding of abundances of elements heavier than iron originating from the $r$-process nucleosynthesis in neutron star mergers and core collapse supernovae requires experimental information from the involved neutron-rich nuclei from close to the neutron-dripline to the line of stability. The $\beta$-delayed neutron emission plays important roles in this process shifting the decay chain...
In this talk I will describe how combining ultrafast lasers and electron microscopes in novel ways makes it possible to directly ‘watch’ the time-evolving structure of condensed matter on the fastest timescales open to atomic motion. By combining such measurements with complementary (and more conventional) spectroscopic probes one can develop structure-property relationships for materials...
Perturbation theory for gravitating quantum systems tends to fail at very late times (a type of perturbative breakdown known as secular growth). We argue that gravity is best treated as a medium/environment in such situations, where reliable late-time predictions can be made using tools borrowed from quantum optics. To show how this works, we study the explicit example of a qubit hovering just...
The $^{137}\mathrm{Ba}^+$ ion is a promising candidate for high-fidelity quantum computing. We generate barium atoms using laser ablation of a $\mathrm{BaCl}_2$ target. The flux of neutral atoms generated by ablation is then ionized near our ion trap-center, giving us trapped ions which we can then use for quantum computing. Laser ablation loading can be used to trap ions more quickly and with...
Accelerator Mass Spectrometry (AMS) provides high sensitivity measurements (typically at or below 1 part in $10^{12}$) for rare, long-lived radioisotopes when isobars (other elements with the same atomic weight as the isotope of interest) can be eliminated. In AMS laboratories, established techniques are used for the removal of the interfering isobars of some light isotopes. However, for...
A crucial task of the ATLAS calorimeter is energy measurement of detected particles. In the liquid argon (LAr) calorimeter subdetector of ATLAS, electromagnetically and hadronically interacting particles are detected through LAr ionization. Special electronics convert drifting electrons into a measurable current. The analytical technique presently used to extract energy from the measured...
Seawater spray and precipitation are two main sources of icing and ice accumulation in cold ocean regions, presenting a major challenge for shipping and operating maritime equipment [1].
There is a limited number of analytical techniques to study seawater spray ice formation. MRI is known for its non-invasive capabilities in measurements of a solid ice [2,3]. In this work, we investigated...
β-delayed neutron emission probabilities of exotic nuclei, along with nuclear masses and β-decay half-lives, are of key importance in the stellar nucleosynthesis of heavy elements via the rapid neutron-capture process (r-process). β-delayed neutron emission influences the final r-process abundance curve through the redistribution of material as neutron-rich nuclei decay towards stability, and...
nEXO is a next generation time projection chamber searching for neutrinoless double-beta decay in 5 tonnes of liquid xenon enriched in the isotope Xe-136. Interactions within LXe produce anti-correlated scintillation and ionization signals, which will be used to reconstruct the energy, position, and multiplicity of each event. Silicon photomultipliers (SiPMs) have been identified as the...
Negative Ion Source Development for Accelerator Mass Spectrometry
CJ Tiessen, WE Kieser, and XL Zhao
Accelerator mass spectrometry (AMS) is a highly sensitive technique used for the analysis of long-lived radioisotopes. While carbon-14 dating is the most well known application, AMS can be used to measure other isotopes such as beryllium-10, aluminum-26, iodine-129, and uranium-236 which are...
For many years the SuperCDMS collaboration has been developing cryogenic
low-threshold silicon and germanium detectors for dark matter searches. The recently developed gram-scale high-voltage eV-resolution (HVeV) detectors are designed to be operated with a high voltage bias (on the order of 100 V) to take advantage of the Neganov-Trofimov-Luke amplification to resolve individual...
Many-body localization impedes the spread of information encoded in initial conditions, providing a intriguing counter point to continuing efforts to understand the approach of quantum systems to equilibrium and also opening the possibility of diverse non-equilibrium phases.
While much work in this area has focused on systems with a single degree of freedom per site, motivated by rapid...
The radioactive decay of radon in the home is the leading cause of lung cancer in non-smoking Canadians (REF 1,2). Radon produced by the decay of uranium and thorium minerals entering the home may accumulate in concentrations that exceed the national maximum guideline for indoor air of 200 Bq/m3. There is a critical need to develop a practical tool to assess an individual’s...
The rare $K^+ \to \pi^+ \nu \bar{\nu}$ decay is an ideal probe for beyond the Standard Model (BSM) physics contributions to the flavor sector. It is heavily suppressed in the SM and its branching ratio is predicted, with remarkable precision for a second order weak process involving hadrons, to be $\left(8.4 \pm 1.0\right) \times 10^{-11}$.
The NA62 experiment at the CERN SPS is designed...
Resonant laser ionization of atoms provides an efficient and selective means for ion source operation. It uses stepwise resonant excitation of an atom's valence electron into energetically Rydberg states or auto-ionizing levels. A resonant ionization laser ion source RILIS is particularly suited to provide beams of rare isotopes at radioactive isotope facilities like ISAC at TRIUMF.
The...
The Laser Interferometer Gravitational-Wave Observatory (LIGO) is expected to begin its fourth observing run in 2022, with a large projected improvement in detector sensitivity. This sensitivity boost increases the gravitational wave (GW) detection rate, but also increases the likelihood of GW events overlapping with transient, non-Gaussian detector noise, or glitches. This project aims to...
Polish up your Klingon (the title is a bit of a teaser; it is a Klingon translation of “Tell me more”)! Effective communication is key when it comes to talking about your research, presenting your research at conferences, and writing papers; Even more so when trying to sell your ideas and research to funding agencies and politicians and decision makers. Lorna Somers has perfected the art of...
The Belle II experiment operating at the SuperKEKB electron-positron collider is the first high energy collider experiment to use CsI(Tl) pulse shape discrimination (PSD) as a new method for improving particle identification. This novel technique employs the particle-dependent scintillation response of the CsI(Tl) crystals which comprise the electromagnetic calorimeter to identify...
The electroweak production of a Z boson in association with two jets is measured using the full Run-II dataset of the ATLAS experiment. This EW-Zjj process is a fundamental process of the Standard Model (SM), it is sensitive to vector boson fusion Z boson production via the WWZ triple gauge vertex. The process is difficult to study, so an advanced methodology is employed to measure the EW-Zjj...
Black holes are, without question, one of the most bizarre and mysterious phenomena predicted by Einstein’s theory of general relativity. They correspond to infinitely dense, compact regions in space and time, where gravity is so extreme that nothing, not even light, can escape from within. And, their existence raises some of the most challenging questions about the nature of space and time....
Computational skills are integral to physics research; they enable the operation of instruments, facilitate the analysis of data, and elucidate physical phenomena through simulation. The same can be said for physics curricula; not only does this reflect the importance in research but incorporating computation into physics courses provides its own pedagogical value. Not surprisingly, many...
High-temperature superconductor YBa2Cu3O7 (YBCO) can be systematically disordered by irradiating with a He-ion beams to induce a metal-insulator transition (MIT). Therefore, tunnel junctions demonstrating Josephson tunneling properties can be constructed in planar YBCO films using a He-ion microscope. We have used superconducting loops with disordered YBCO junctions to develop devices that...
Studies of atomic nuclei furthest from stability often reveal surprising phenomena such as exotic structures, highly-deformed shapes and rare modes of radioactive decay. Understanding the properties of the most exotic nuclei is crucial for constraining nuclear reaction rates in explosive astrophysical scenarios and explaining the elemental abundances of the stable and radioactive isotopes...
In this talk, recent highlights and future prospects will be discussed.
We propose a driving scheme in dynamic Atomic Force Microscopy (AFM) to maximize the time the tip spends near the surface during each oscillation cycle. Using a quantum description of the oscillator that employs a generalized Caldeira-Leggett model for dissipative oscillator-surface interaction, we predict large classical squeezing and a small amount of skewness of the probability distribution...
Measurements of correlation parameters in nuclear β decay have a long history of helping shape our current understanding of the fundamental symmetries governing our universe: the standard model. A variety of observations indicate this model is incomplete, so scientists continue to search for what may lie beyond the standard model. Nuclear β decay continues to play an important role in this...
Temporal diffusion spectroscopy (TDS) has been used to infer axon sizes using geometric models that assume axons are cylinders. A celery sample was imaged to test if the importance of other geometric models. The vascular bundles and collenchyma tissue (~20 μm cells) in celery can be modeled as containing cylindrical cells. Whereas the parenchyma cells are rounder and are 3-4 times larger in...
A crucial challenge in engineering modern, integrated systems is to produce robust designs. However, quantifying the robustness of a design is less straightforward than quantifying the robustness of products. For products, in particular engineering materials, intuitive, plain language terms of strong versus weak and brittle versus ductile take on precise, quantitative meaning in terms of...
In numerical relativity, marginally outer trapped surfaces (MOTSs) (often referred to as apparent horizons) are the main tool to locate and characterize black holes. For five decades it has been known that during a binary merger, the initial apparent horizons of the individual holes disappear inside a new joint MOTS that forms around them once they are sufficiently close together. However the...
The common picture of a binary black hole merger is the “pair of pants” diagram for the event horizon. However, in many circumstances, such as those encountered in numerical simulations, the event horizon may be ill-suited and it is more practical to work with quasi-local definitions of black hole boundaries, such as marginally outer trapped surfaces (MOTS). The analog of the pair of pants...
The quest to engineer quantum computers of a useful scope faces many challenges that will require continued investigation of the physics underlying the devices. In this talk, we focus on trapped ion quantum computing. We discuss our efforts to implement quantum information processing with Ba+ ions and provide an overview of possible future benefits this ion could provide for quantum computing...
Graphene is among the most promising materials considered for next-generation gas sensing due to its properties including high mechanical strength and flexibility, high surface-to-volume ratio, large conductivity, and low electrical noise. While gas sensors based on graphene devices have already demonstrated high sensitivity, one of the most important figures of merit, selectivity, remains a...
Positron Emission Tomography (PET) images of the brain can reflect the level of brain molecular metabolism with low spatial resolution, while magnetic resonance imaging (MRI) brain images can provide anatomical structure information with high spatial resolution. In order to achieve the complementary of molecular metabolism information and spatial texture structure, it is meaningful to fuse the...
In the case of binary black hole mergers, the surface of most obvious interest, the Event Horizon, is often computationally difficult to locate. Instead, it is useful to turn to quasi-local characterizations of black hole boundaries, such as Marginally Outer Trapped Surfaces (MOTS), which are defined for a single time slice of the spacetime, and the outer-most of which is the apparent...
Despite the constant stream of black hole merger observations, black hole mergers are not yet fully understood. The phenomenon seems simple enough, but the details of how the two apparent horizons end up as one horizon is unclear due to the non-linear nature of the merger process. Recent numerical work has shown that there is a merger of self-intersecting Marginally Outer-Trapped Surfaces...
We propose an efficient, nanoplasmonic method to selectively enhance the spontaneous emission rate of a quantum system by changing the polarization of an incident control field, and exploiting the polarization dependence of the system's spontaneous emission rate. This differs from the usual Purcell enhancement of spontaneous emission rates as it can be selectively turned on and off. Using a...
I was a graduate student in Jules Carbotte's group in the early 1990s, during the heyday of high temperature superconductivity. At the time (for me), everything was new and everything was exciting and it felt as if we were about to learn something beautiful about the world. I recognize now how many of those feelings are tied to where I was and who I was working for. Indeed, I have much to...
Chemical warfare agents (CWAs) are potential threats to civil society and defence personnel. In recent years, many efforts has been deployed to develop a scalable, rapid and accurate detection system to identify trace amount of CWAs. Here we report a graphene-based field-effect transistor (GFET) sensor able to detect 800 ppb of dimethyl methyl phosphonate (DMMP), a simulant of the nerve agent...
Tissue microstructure, such as axon diameters, can be inferred from MRI diffusion measurements either through relating models of the geometry of the tissue and MR parameters, or through directly relating MR measurements to tissue parameters. Some have implemented geometric models to infer axon diameters using temporal diffusion spectroscopy. In order to target smaller diameter axons, we have...
The observation of supermassive black holes (SMBHs) of mass over a billion solar masses within the first billion years after the Big Bang challenges standard models of the growth of massive objects. Direct collapse black holes arising from a short-lived supermassive star phase have been proposed as a means to form the SMBHs in the required time. In this work we show that a weak cosmological...
Magnetic Resonance Imaging (MRI) detects signal from hydrogen nuclei in biological tissue. MRI requires a homogeneous static magnetic field to generate artifact-free images. The subject is spatially encoded with magnetic field gradients. The signal is acquired in the frequency domain and the image is reconstructed by inverse Fourier transform. Objects with high magnetic susceptibility, such as...
One of the more exciting things to emerge from black hole thermodynamics in the past 10 years is the understanding that black holes can undergo a broad range of chemical-like phase transitions, including liquid-gas phase transitions, triple points, superfluid transitions, polymer-type transitions, and exhibit critical behaviour. It is even possible to consider black holes as the working...
Graphene field effect transistors (GFETs) have an enormous potential for the development of next-generation gas sensors, but more efforts are required to improve their sensitivity and selectivity. In this talk we discuss UV illumination as a promising method to enhance the performance of GFETs for the detection and recognition of analytes such as ethanol, water vapor and dimethyl...
Time-resolved spectroscopy of multi-electron dynamics associated with the Xe giant plasmonic resonance is demonstrated by applying an attosecond in situ measurement method. The Xe giant resonance was first noticed through enhanced photoionization around 100 eV using synchrotron X-ray beams. Recently, this was revisited with high harmonic spectroscopy, where enhanced extreme ultraviolet (XUV)...
One of the more exciting things to emerge from black hole thermodynamics is that black holes can form the working material for heat engines. I explore the connection between the critical behaviour of black holes and their efficiency as heat engines over a range of dimensions and for a variety of theories of gravity.
I first show that their efficiency as heat engines near the critical point...
The study of many-body quantum systems undergoing non-equilibrium dynamics has received a lot of interest in the past few years. One way to characterize such systems is by monitoring non-analytic behavior of physical quantities that might occur as a function of time. This is precisely the aim of the theory of dynamical phase transitions. Another way is by looking at universal structures that...
Introduction: pHi is a hallmark of altered cellular function in the tumour microenvironment and its response to therapies. One of the main acid-extruding membrane transport proteins in cells is the Na+/H+ exchanger isoform 1 (NHE1). Chemical exchange saturation transfer (CEST) MRI uniquely images pHi. In CEST-MRI, contrast is produced by exciting exchangeable tissue protons at their...
This talk will focus on an overview of Eliashberg theory, a formalism that Jules was very well known for. But I will also discuss some potential shortcomings of this framework, as time permits, from the weak coupling to the strong coupling limit, with polaron physics, and applicability to the hydride and superhydride materials.
In this work we explore the use of multi-layer graphene (MLG) films grown by chemical vapor deposition for adaptive thermal camouflage. Using different ionic liquids, we tune the opto-electronic properties of MLG (150 – 200 layers) and investigate changes in optical reflectivity and emissivity in the infrared region (IR). We fabricate devices having a metallic back electrode supporting a...
We examine the thermodynamics of a new class of asymptotically AdS black holes with non-constant curvature event horizons in Gauss-Bonnet Lovelock gravity, with the cosmological constant acting as thermodynamic pressure. We find that non-trivial curvature on the horizon can significantly affect their thermodynamic behaviour. We observe novel triple points in 6 dimensions between large and...
High harmonic generation (HHG) in gasses has become a method of choice among table-top extreme ultraviolet (XUV) sources. In order to generate higher photon energies from this process, many strategies can be implemented, including red-shifting and compressing the driver pulses. Here, we propose a new approach for inducing a red-shift to driver pulses and compressing them to few-cycle durations...
Additional spatial dimensions compactified to submillimeter scales serves as an elegant solution to the hierarchy problem. As a consequence of the extra-dimensional theory, primordial black holes can be created by high-energy particle interactions in the early universe. While four-dimensional primordial black holes have been extensively studied, they have received little attention in the...
As the most recently-discovered particle of the Standard Model, the Higgs boson is fundamental to our understanding of particle physics and is the focus of much attention at CERN’S Large Hadron Collider (LHC). The Higgs boson’s couplings to other particles are predicted by the Standard Model (SM), so performing precise measurements of these couplings can probe for discrepancies and constrain...
The proton drip-line is not firmly established for heavy masses. Near N=82, the masses of neutron-deficient Yb and Tm isotopes were measured. In Tm (Z=69), the precise location of the drip-line could be determined, and for both isotopic chains the stabilizing effect of the N=82 shell was examined. These elements now represent the largest atomic numbers at which this shell closure has been...
**Introduction:** MRI’s low sensitivity, caused by the use of nuclei with low-gyromagnetic ratios or low magnetic field strength, can presently be improved with expensive high-field MRI-hardware and/or expensive enriched-isotopes. We propose a new method that does not require any extra signal-averaging or hardware to improve the quality of MRI images. We will use a significant k-space...
The science and technology of alkanethiol self-assembled monolayers (SAMs) on gold and other solid surfaces is a subject of ongoing research driven by the fundamental interest and attractive practical applications. The structural organization of alkanethiol SAMs is dominated by the strong intermolecular interaction, manifested by the enhanced quality of SAMs formed by long chain alkanethiols....
Globular clusters contain some of the oldest stars in the universe and provide a key method of understanding the formation and evolution of galaxies. Unfortunately, there are a number of mysteries about the history of globular clusters. One of the most important is the existence of multiple populations, and evidence that the current generation of stars within globular clusters has been...
Time-domain terahertz (THz) spectroscopy has been widely exploited in studying semiconductors, superconductors, topological insulators, and metal-organic frameworks. A high-sensitivity THz system can resolve weak spectroscopic features and a broadband system allows experimentalists to rely on additional spectral information to investigate novel phenomena in materials. In a standard...
Covid-19 project: What a physics instructor learned by working with engineering coop students to create open problems using WeBWorK
BCcampus has funded a number of projects to increase the use of Open Educational Resources (OER) in the British Columbia. There are initiatives to make either Zero (or low cost) Textbook Credentials. One of the major stumbling blocks to having all first-year...
The National Research Council Canada (NRC) was contracted by Infrastructure Canada and the City of Toronto to improve the understanding of the performance of various catch basin covers under various conditions. A full scale model roadway was built 10.7 m long and 2.6 m wide in the NRC's Coastal Wave Basin and the water depth in front of the catch basin varied from 0.5 - 15 cm, the road grade...
Magnetic resonance imaging (MRI) is widely used as a non-invasive diagnostic technique to visualize the internal structure of biological systems. MRI has limited spatial resolution and the microscopic behaviour within an image voxel cannot be visualized with qualitative images. Quantitative analysis of molecular diffusion provides insights into the microscopic structure beyond the MRI image...
In this research project, I calculated the high-harmonic spectrum from a 1D periodic potential. I investigated numerical methods for solving the 1D time-dependent Schrodinger equation of a particle in a double-well potential, as well as determining its ground state. I used the Crank Nicolson method [1], which is a finite difference method that can be used for numerically solving second-order...
Molybdenum possesses seven stable isotopes and the relative amounts of these isotopes are found to vary in nature. This is because physical and chemical processes can redistribute the isotopes in a system due to the differences atomic masses. Specific processes can leave an “isotopic fingerprint” that may be recorded in the isotopic composition of the element in a given sample. The...
In the Standard Model, the interactions between gauge bosons are completely specified and any deviations from this expectation would indicate the presence of new physics phenomena at unprobed energy scales. The study of the self-couplings of electroweak gauge bosons is therefore a powerful approach to searching for new physics phenomena. The large data samples collected by the ATLAS experiment...
The investigation of radiative capture reactions involving the fusion of hydrogen or helium is crucial for the understanding of stellar nucleosynthesis pathways as said reactions govern nucleosynthesis and energy generation in a large variety of astrophysical burning and explosive scenarios. However, direct measurements of the associated reaction cross sections at astrophysically relevant low...
High harmonics generation (HHG) in solids is a decade old field and yet the understood mechanisms leading to HHG is still an incomplete picture. They fail to capture real-space motion like lateral tunneling ionization. We investigate theoretically high harmonic generation in solids using a localized basis of Wannier states. Wannier states are localized wavefunctions overcoming the infinite...
High-power lasers are rapidly becoming standard tools in advanced manufacturing, mainly in the form of laser welding, laser cutting, and laser additive manufacturing. Of these applications, laser welding in the electric mobility sector---particularly in the manufacturing of battery packs---presents unique challenges. Weld depth needs to be precisely controlled, not only to ensure joint...
A polarized electron beam is being considered as an upgrade for the SuperKEKB accelerator. Having a polarized beam at Belle II opens a new precision electroweak physics program, as well as improving sensitivity to dark sector and lepton flavour violating processes. In order to achieve a polarized beam at SuperKEKB a variety of hardware and technical challenges are being studied. The limiting...
The main advantage of hybrid PET-MR imaging systems is the ability to correlate anatomical with metabolic information directly. The bulk of commercially available PET-MR systems are quite large and expensive and mostly used on humans rather than for preclinical animal studies. This has led to a gap of knowledge in PET-MR imaging of small animal models used in preclinical research. Our work...
Experimentally-derived rates of selected charged-particle induced capture reactions are key ingredients in our global understanding of stellar nucleosynthesis. In particular, selected resonant proton and alpha capture reactions on medium-mass stable and radioactive targets are important for nucleosynthesis in a variety of scenarios such as classical novae and the $p$ and $rp$-processes, which...
Ion traps have long been recognized as superb precision tools for fundamental physics research.
In contemporary nuclear physics, they are widely employed to prepare, control and study short lived radionuclides with high precision and accuracy. Over the last decade, Multi-Reflection Time-of-Flight (MR-ToF) mass separators have significantly gained in importance at radioactive ion beam (RIB)...
The phase-out of ozone depleting substances has led to the release in the atmosphere of new generations of fluorinated coolants and propellants. Those molecules contain C-F bonds, which make them strong absorbers in the mid-infrared spectral region. To properly assess the impact of those molecules on climate, their radiative forcing must be calculated from their experimental and/or theoretical...
We discuss interaction of gravitational waves with matter including plasma and its implications for cosmology.
Our universe is a dynamic, fascinating, and beautiful place. Yet, physics is sometimes perceived as being dry and lacking cultural engagement. To mitigate that perception, we are engaging two powerful partners: our physical universe and our local culture.
The talk will describe a scientific and cultural outreach program developed for underrepresented youth in Newfoundland and Labrador, which...
We present a study of the evolution of entanglement entropy of matter and geometry in quantum cosmology. We show that entanglement entropy increases rapidly as the Universe expands, and then saturates to a constant non-zero value. The saturation value of the entropy is a linear function of the energy E associated to the quantum state: S=γE. This result suggests a ‘First Law’ of matter-gravity...
Calcium (Ca) is an essential mineral in the body that helps maintain healthy bone density. Dysreguation of Ca can result in serious health issues and a reliable and efficient method of identifying changes in bone mineral balance can help to provide eaarly diagnosis of deteriorating bone health. The objective of this project is to investigate the application of naturally occurring Ca isotope...
Floquet theory is useful for understanding the behaviour of quantum systems subject to periodic fields. Ho et al. [Chem. Phys. Lett. 96, 464 (1983)] have presented an extension of Floquet theory to the case of systems in the presence of multiple periodic fields with different frequencies. However, unlike conventional Floquet theory, which is well-established, many-mode Floquet theory...
We report a formal analogy between cosmology and earth science. The history of a closed universe is analogous to an equilibrium beach profile (i.e., the depth of the water as one recedes from a beach moving seaward). A beach profile reaches equilibrium in summer and in winter and is described by a variational principle that minimizes energy dissipation. The oceanography side of the analogy...
It has been shown beyond reasonable doubt that about 95% of the total energy budget of the universe is given by the dark constituents, namely Dark Matter and Dark Energy. What constitutes Dark Matter and Dark Energy remains to be satisfactorily understood however, despite a number of promising candidates. An associated conundrum is that of coincidence, as to why the Dark Matter and Dark Energy...
The ATLAS Experiment at CERN is a general-purpose particle physics detector that measures properties of particles created in high-energy proton-proton collisions fueled by CERN’s Large Hadron Collider (LHC). Searching for undiscovered particles is exciting, but there is still much to be learned about the particles that we know to exist in the Standard Model by making precision measurements of...
Introduction: A non-invasive imaging method: inhaled hyperpolarized (HP) 129Xe magnetic resonance imaging (MRI) is currently used to measure lung structure and function.1 Simultaneous ventilation/perfusion (V/P) lung measurements of functional gas exchange within the lungs can be obtained using this MRI approach because of the high solubility of xenon in lung tissue as compared to...
Laser resonance ionization (mass) spectroscopy in a hot cavity environment is an ultra-sensitive means for laser spectroscopy of short-lived isotopes. Despite the non-Doppler free nature of hot cavity, in source spectroscopy, this method allows to determine atomic energy levels and through Rydberg series convergence the determination of the first ionization potential. An overview of the...
False vacuum decay in quantum mechanical first order phase transitions is a phenomenon with wide implications in cosmology, and presents interesting theoretical challenges. In the standard approach, it is assumed that false vacuum decay proceeds through the formation of bubbles that nucleate at random positions in spacetime and subsequently expand. In this paper we investigate the presence of...
In this joint experimental and theoretical work [1], photoelectron emission from excited states of laser-dressed atomic helium is analyzed. We successfully demonstrate a method that is complimentary to transient absorption (e.g. [2]) for the assignment of light-induced states (LIS). The experiment is carried out at DESY in Hamburg and uses the FLASH2 free-electron laser to produce an extreme...
Cosmology presupposes that on scales of $10^{8}$ light years the universe is the same at every point and in every direction. This is observationally supported by the cosmic microwave background (CMB) which has a temperature of 2.7 Kelvin in all directions. However, there exist small perturbations on this symmetric background - for example the CMB has perturbations of 0.001 Kelvin. A study of...
Introduction: A great challenge in quantitative dynamic positron emission tomography (PET) imaging is to determine the exact volumes of interest (VOI) with which one wants to work. They have a tremendous impact on the time-activity curves that are used to extract the pharmacokinetic coefficients. Since PET images are functional and not anatomical, using a bijective relationship with a computed...
Undergraduate research activities, strong mentorship and peer support have been demonstrated to improve the experiences of students studying science in the last few years and the community has grown on campus. The University of Winnipeg has a large number of Indigenous students per capita, and is uniquely situated to support and encourage Indigenous students in the sciences. This presentation...
While Big Bang cosmology successfully explains much of the history of our universe, there are certain features it does not explain, for example the spatial flatness and uniformity of our universe. One widely studied explanation for these features is cosmological inflation. I will discuss the gravitational wave spectra generated by inflaton field configurations oscillating after inflation for...
Magnetic Resonance Imaging (MRI) is a powerful imaging modality with excellent soft tissue contrast. Contrast agent such as iron oxide nanoparticles can be used to “tag” individual cells, distorting the magnetic field around them and allowing the imaging of single cells. Time-lapse MRI can be used to track the motion of tagged cells, providing insights in the studies of inflammatory diseases...
The SuperKEKB is a high luminosity e+e- collider with a circumference of 3km located in Japan, which collides 7GeV electrons with 4GeV positrons for precision flavour studies, CP violation, and searches for new physics. We are aiming at upgrading the SuperKEKB with a polarized electron beam, which would provide high precision neutral current electroweak and other measurements. To polarize the...
The purpose of this presentation is to recognize the effects of electromagnetic energy injection into the early Universe from decaying sub-GeV dark vectors. Decay widths and energy spectra for the most prominent channels in the sub-GeV region are calculated for various dark vector models. The models include the kinetic mixing of the dark photon with the Standard Model photon, $U(1)_{A'}$ , a...
Much of what we know of the early universe comes from observations of the cosmic microwave background (CMB): a 13 billion-year-old field of microwave radiation that permeates the entire universe. Recent technological advances have made real the possibility of combining CMB measurements with other large data sets to extract hitherto inaccessible cosmological information. One such example is the...
Nuclear isotopes are nuclei with a fixed number of protons Z but with a varying number of neutrons N. The question of how many neutrons a certain element can have while maintaining its stability against neutron or proton emission, or in other words where the proton and neutron drip-lines lie, has been troubling not only nuclear physicists but also astrophysicists since it can help answering...
Magnetic resonance imaging (MRI) is widely used as a non-invasive diagnostic technique to visualize the internal structure of biological systems. Quantitative analysis of magnetic resonance signal lifetimes, i.e., relaxation times, can reveal molecular scale information and has significance in the study of brain, spinal cord, articular cartilage, and cancer discrimination. Determination of MR...
The nuclear-polarized beam facility at TRIUMF-ISAC provides radioactive ion beams, highly polarized by laser collinear optical pumping, to several experimental stations. It has successfully delivered 8,9,11Li, most Na isotopes, and 31Mg over the last 20 years for studies in material science, biochemistry, nuclear physics, and fundamental symmetries. An overview of the polarizer facility will...
Since the discovery of the Higgs boson with a mass of about 125 GeV in 2012 by the ATLAS and CMS Collaborations, an important remaining question is whether this particle is part of an extended scalar sector as postulated by various extensions to the Standard Model. Many of these extensions predict additional Higgs bosons, motivating searches in an extended mass range. Here we report on a...
Positron Emission Tomography (PET) Imaging of the brain might become the most effective imaging technique to predict Alzheimer's disease. However, the definition of the brain in PET images is low and the lesion area is not easy to define, so the accuracy of traditional machine learning algorithms in predicting Alzheimer's disease from PET images is low. Deep learning algorithms can effectively...
Zinc-65 (Zn-65) is a radionuclide of interest in the fields of medicine and gamma-ray spectroscopy, within which its continued use as a tracer and common calibration source necessitates increasingly-precise nuclear decay data. A Zn-65 dataset was obtained as part of the KDK ("potassium decay") experiment, whose apparatus consists of an inner X-ray detector and an efficient outer detector, the...
Mass measurement facilities are extremely important in furthering our understanding of nuclear structure away from the valley of stability, including aiding in the search for collective behaviors in exotic nuclei. TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN) is among the world’s premier precision trapping facilities, with the newly added Multiple-Reflection Time-of-Flight Mass...
Remarks and comments on issues of interest in Cosmology followed by questions, answers and discussions with a panel on a set of pre-distributed list of interesting challenges in cosmology.
The inertial confinement fusion scheme relies on the implosion of a Deuterium-Tritium pellet by the means of tens of laser beams. At maximum of compression, extreme thermodynamic conditions must be reached in order to trigger a thermonuclear wave. Laser-plasma interaction, for such large spatial and temporal scales, may only be described numerically with specific hydrodynamic codes. In the...
As science probes ever more extreme facets of the universe, the role of nuclear theory in confronting fundamental questions in nature continues to deepen. Long considered a phenomenological field, breakthroughs in our understanding of nuclear and electroweak forces in nuclei are rapidly transforming modern nuclear theory into a true first-principles, or ab initio, discipline.
In particular...
Physics degree holders are among the most employable in the world, often doing everything from managing a research lab at a multi-million dollar corporation, to developing solutions to global problems in their own small startups. Science and Technology employers know that with a physics training, a potential hire has acquired a broad problem-solving skill set that translates to almost any...
MBT for TBM (Topological Band Magnetism)
A.H. MacDonald, C. Lei, Shu Chen, O. Heinonen, and R.J. McQueeney
Physics Department, University of Texas at Austin 78712 USA
Bulk MnBi2Te4 and MnBi2Se4 are antiferromagnetic topological insulators [1], and also van der Waals compounds with weakly-coupled seven-atom-thick (septuple) layers. I will discuss the electronic, magnetic, and topological...
Microfluidic technology has been used in many application areas including diagnostics, drug delivery and drug discovery. In drug discovery, microfluidic devices have been used to perform combinatorial experiments where several drug candidates can be exposed to biological materials such as protein drug targets, cells or small organisms simultaneously at various concentrations in order to...
In recent years the prospects of quantum machine learning and quantum deep neural network have gained notoriety in the scientific community. By combining ideas from quantum computing with machine learning methodology, quantum neural networks (QNNs) promise new ways to interpret classical and quantum data sets. However, many of the proposed quantum neural network architectures exhibit a...
This keynote will provide a high-level overview of the current state-of-the-art in quantum technologies and their applications to sensing, imaging and metrology. I will start with a brief historical view about how National Metrology Laboratories like NIST and NRC-Canada have used these technologies for years. I will then transition to some near-term commercial applications before returning...
At relativistic intensities, electrons can be driven close to the speed of light, facilitating exploration of a new regime of laser-plasma interactions and high-field science. These intense pulses can drive matter into extreme states of temperature and pressure, mimicking those typically found in astrophysical environments, and leading to the observation of new states of high-energy-density...
I will review the present and near-term future prospects for new
cosmology results with 21cm probes. This is a
technology-driven observational field and I will describe experimental
challenges and enabling technology in parallel with the science.
The discovery of the lepton-number-violating neutrinoless double-beta decay process will prove that neutrinos are Majorana fermions. The Large Enriched Germanium Experiment for Neutrinoless double-beta Decay (LEGEND) project will search for this decay in $^{76}$Ge. In its first phase — LEGEND-200 — 200~kg of $^{76}$Ge-enriched high-purity germanium detectors will be deployed in a...
Tajima and Dawson proposed the idea of laser-wakefield accelerators (LWFAs) during the late 1970s. LWFAs produce low transverse emittance, ultrashort electron bunches of few femtoseconds duration with the potential to drive free electron lasers and compact X-ray and gamma-ray sources. Through the implementation of high-gradient quadrupole magnets, it is possible to focus and transport LWFA...
Since many concepts in theoretical physics are well known to scientists in the form of equations, it is possible to identify such concepts in non-conventional applications of neural networks to physics.
In this talk we examine what is learned by convolutional neural networks, autoencoders or siamese networks in various physical domains. We find that these networks intrinsically learn physical...
Non-invasive liquid biopsies offer hope for point-of-care glimpse into the molecular hallmarks of the disease, including drug resistance and targets. Among different types of liquid biopsy platforms, tumor-derived exosomes (EXs) are unique due to their intercellular tumor communication and serve as carriers of biological information. Exosomes are nanoscale extracellular vesicles (EVs) released...
Line Intensity Mapping has emerged as a powerful tool to probe the large-scale structure across a wide range of redshift, with the potential to shed light on dark energy at low redshift and the cosmic dawn and reionization process at high redshift. Multiple spectral lines, including the redshifted 21cm, CO, [CII], H-alpha, and Lyman-alpha emissions, are promising tracers in the intensity...
Single-photon detectors are being increasingly implemented in a variety of applications ranging from quantum information science to spectroscopy and remote sensing. These measurement techniques rely on the accurate detection of single photons at specific wavelengths. National metrology institutes worldwide, including the National Research Council Canada, have been developing characterization...
The nonlinear behavior of absolute stimulated Raman scattering (SRS) near the quarter-critical density is investigated using one-dimensional (1D) Vlasov simulations with parameters relevant to ignition-scale direct-drive coronal plasmas. Numerical Vlasov simulations show that a strong and stable Airy pattern is formed by the Raman light as it is generated near its cutoff density. This...
Novel therapeutic strategies are urgently needed to control the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) pandemic. This virus belongs to a larger class of corona viruses currently circulating, which pose major threats to global public health. Here, I present the fabrication and characterization of Erythro-VLPs: Erythrocyte-Based Virus Like Particles, i.e., red blood cell...
IBM Watson is well known for industry-leading natural language processing that defeated defending champions [on Jeopardy!][1] and most recently, [learned to debate complex topics with humans][2]. Equally as exciting, though perhaps less publicized, IBM works with government, enterprise, and industry to apply machine learning to real world applications such as customer care. This talk offers...
We report the observation of a giant c-axis nonlinear anomalous Hall effect in the non-centrosymmetric Td phase of MoTe2 without intrinsic magnetic order. Here, application of an in-plane current generates a Hall field perpendicular to the layers. By measuring samples across different thicknesses and temperatures, we find that the nonlinear susceptibility obeys a universal scaling with sample...
Neutrinos present a portal into understanding some of the most significant puzzles of modern physics, even as the nature of the neutrino is still mysterious. SNO+ is well positioned to examine some of those puzzles. Located 2 km underground in the Vale Creighton mine in Sudbury at the international facility SNOLAB, SNO+ is the largest liquid scintillator neutrino detector currently in...
In this talk, I will introduce a generalization of the earth mover's distance to the set of quantum states. The proposed distance recovers the Hamming distance for the vectors of the canonical basis, and more generally the classical earth mover's distance for quantum states diagonal in the canonical basis. I will discuss some desirable properties of this distance, including a continuity bound...
Experiments performed at the National Ignition Facility (NIF) have provided evidence that stimulated Raman scattering (SRS) occurs at a level that poses a preheat risk for directly-driven inertial confinement fusion implosions [1]. To help investigate the mechanisms responsible for the generation of this SRS, recent experiments on the OMEGA EP laser (in which similar SRS signatures were...
As a result of the growing world-wide antibiotic resistance crisis, many currently existing antibiotics have been shown to be ineffective due to bacteria developing resistive mechanisms. There are a limited variety of potent antibiotics that are successful at suppressing microbial growth, such as polymyxin B, however, are deemed as a last resort due to their high toxicity. Adverse side effects...
During the Covid-19 pandemic, face masks have become the new norm with their widespread use in public as part of a multi-barrier approach for infection control, including physical distancing, hand hygiene, and altered social behaviour. Masks provide benefits to both the mask wearer and to those in their proximity when they are worn by all individuals in a common area. The gold standard in...
Social distancing measures have been the main non-pharmaceutical intervention (NPI) against the COVID-19 pandemic. Numerous large-scale analyses have studied how these measures have affected human movement, finding sizeable drops in average mobility. Yet comparatively little attention has been paid to higher-order effects such as “superspreading events” which are known to be outsized drivers...
Coming soon!
nEXO is a proposed next generation neutrinoless double beta decay experiment. The detector is a single-phase time projection chamber filled with 5 tonnes of liquid xenon enriched in {136}^Xe, designed for a half-life sensitivity of ~$10^{28}$ yr. Events in the detector will result in both ionization and scintillation signals, read out by separate electronic systems. Scaling up from the...
For a lot of us, the COVID-19 pandemic has meant dialing back, hunkering down, and holding off until things get back to normal. For some, though, it has meant ramping up and going the extra mile to get things back to normal. This presentation will attempt to tell a story that starts with a small group of students from Lakehead University and the Northern Ontario School of Medicine that...
As a trained experimental scientist, when it became clear that I needed to transition to industry I was left to find something that fit my skills. Data science offered that opportunity. I have worked in numerous industries including health care, fintech, oil and gas, and agriculture applying statistical knowledge and machine learning (ML) techniques. Knowledge from my physics degree set me up...
Mechanical systems represent a fundamental building block in many areas of science and technology, from atomic-scale force sensing to quantum information transduction to kilometer-scale detection of infinitesimal spacetime distortions. All such applications benefit from improved readout sensitivity, and many seek new types of mechanical actuation. In this talk I will discuss our efforts to...
The suppression of turbulence in fusion plasmas, crucial to the success of next-generation tokamaks such as ITER, depends on a variety of physical mechanisms including the shearing of turbulent eddies via zonal flow and possibly the generation of intrinsic rotation. The turbulence exhibits interesting features such as avalanche structures and self-organisation, and its absence is associated...
Study of high-confinement mode (H- mode) of tokamak operation plays an important role to optimize conditions for fusion reactors. Many experimental techniques, including electrode biasing and resonant magnetic perturbations (RMP), have been developed to improve the plasma confinement, facilitating transition from low to high confinement mode (L-H transition) and to study the transition...
There exists an unconventional class of waves known as thermal diffusion waves, or simply thermal waves, that are produced using sinusoidally, time-varying heat sources and they can be used to determine the thermal conductivity in the medium. Recent advancements have resulted in the construction of thermal wave resonator cavities (TWRCs) capable of sustaining quasi-standing thermal waves which...
After 3 decades of preparation, tools and procedures for reproducible fabrication of atom-perfect silicon structures have matured to a point where it has now become possible to build proto-devices while also planning viable atom-scale manufacturing. In the beginning, device complexity and production rates will be low while manufacturing costs are high, challenges that must be offset by the...
The Deep Underground Neutrino Experiment (DUNE) is a next-generation long-baseline neutrino oscillation experiment. DUNE’s main goal is to provide unprecedented sensitivity in the search for neutrino CP violation, to determine the neutrino mass hierarchy, and to make precision measurements of neutrino mixing parameters. DUNE will be sensitive to low-energy neutrinos coming from supernova...
The effects of the modification of the electron distribution function in the nonlinear regime of the Buneman instability and statistical noise effects have been investigated, using high-resolution Vlasov and Particle-in-Cell simulations. It is shown that this modification is a result of electron trapping. In nonlinear regimes, electron trapping and associated modification of the electron...
T2K and Super-Kamiokande (Super-K) in Japan represent the current generation of successful campaigns to understand the properties of neutrino mixing, using detectors whose physics reach also extends to studies of astrophysical neutrinos and searches for new physics through processes such as nucleon decay or dark matter annihilation. T2K utilizes Super-K as the far detector in a long-baseline...
Introduction: Three-dimensional transrectal ultrasound (3D TRUS) imaging is utilized in prostate cancer diagnosis and treatment, necessitating manual prostate segmentation which is time-consuming and difficult. The purpose of this work was to develop a generalizable and efficient deep learning approach for automatic prostate segmentation in 3D TRUS, trained using a diverse dataset of...
In this presentation you'll see how to use TensorFlow Quantum to conduct large scale research in QML. The presentation will be broken down into two major sections: First you will follow along as we implement and scale up (beyond the authors original size) some existing QML works from the literature in TensorFlow Quantum. We will focus on how to write effective TensorFlow Quantum code,...
In this talk, I will describe my efforts to understand the nature of the mysterious dark matter. I provide an overview of the general problem and then describe my current approach to it, which is to characterize the behavior of a proposed dark matter particle, the axion. I will give some insight into how I am using a range of tools -- model building, computation, and high energy astrophysics...
Entanglement is the essential resource that defines this new paradigm of quantum-enabled devices. Here I confirm the long-standing prediction that a parametrically driven mechanical oscillator can entangle electromagnetic fields. We observe stationary emission of path-entangled microwave radiation from a micro-machined silicon nanostring oscillator, squeezing the joint field operators of two...
Magnetic atoms on superconductors induce an exchange coupling, which leads to states within the superconducting energy gap. These so-called Yu-Shiba-Rusinov (YSR) states can be probed by scanning tunneling spectroscopy at the atomic scale. Here, we investigate single magnetic adatoms on a superconducting Pb surface.
As YSR states are within the superconducting energy gap, their excitation by...
Engineering of defects located in-grain or at grain boundary is central to the development of functional materials and nanomaterials. While there is a recent surge of interest in the formation, migration, and annihilation of defects during ion and plasma irradiation of bulk (3D) materials, the detailed behavior in low-dimensional materials remains most unexplored and especially difficult to...
Dark matter could be a "thermal-ish" relic of freeze-in, where the dark matter is produced by extremely feeble interactions with Standard Model particles dominantly at low temperatures. In this talk, I will discuss how sub-MeV dark matter can be made through freeze-in, accounting for a dominant channel where the dark matter gets produced by the decay of plasmons (photons that have an in-medium...
Chilling an underground mining project becomes more costly as the depth increases. The air temperature increases as it descends due to auto-compression, additional heat from the host rock, equipment and processes is inevitable. A move to battery powered vehicles may allow for less air flow, legislation changes pending, but battery powered vehicles and the charging process liberate heat. The...
Despite an undeserved reputation for being hard to understand, the mathematics behind quantum computing is based on relatively straightforward linear algebra. This means that the equations governing quantum computing are intrinsically differentiable. This simple observation has remarkable consequences. In particular, many of the tools developed over the past decades for deep learning, such as...
Majorana bound states are zero-energy states predicted to emerge in topological superconductors and intense efforts seeking a definitive proof of their observation are still ongoing. A standard route to realize them involves antagonistic orders: a superconductor in proximity to a ferromagnet. Here, we show that this issue can be resolved using antiferromagnetic rather than ferromagnetic order....
Dosimetry is an important part of radiation therapy, ensuring the prescribed treatment is delivered to the patient and avoiding accidental overexposure of adjacent healthy tissue. This includes characterizing proton beams for proton therapy. However, patients in proton therapy facilities are typically also exposed to secondary neutron fields, that are generated in all materials intercepted by...
Radiotherapy and chemotherapy are the gold standard for treating patients with cancer in the clinic but, despite modern advances, are limited by normal tissue toxicity. The use of nanomaterials, such as gold nanoparticles (GNPs), to improve radiosensitivity and act as drug delivery systems can mitigate toxicity while increasing deposited tumor dose. To expedite a quicker clinical translation,...
Effective local therapy is needed to avoid local progression of the tumor, which may further decrease the development of systemic metastases and increase the possibility for resection. Radiation therapy (RT) is frequently used to locally treat the tumor. One of the major issues in RT for treating cancer is the close proximity of adjacent organs at risk, resulting in treatments doses being...
The DND/CAF is faced with a rapidly evolving defence, safety, and security environment with the emergence of disruptive technologies such as quantum. It is expected that some disruptive technologies, quantum in particular, will have an impact in less than 5 years. Quantum-enabled technologies will have applicability across a wide array of defence applications, such as in sensing (including...
Diacetylene molecules can self-assemble into crystals, with three-dimensional packing and separation between molecules dictated by the chemical groups on either side of the carbon-carbon triple bonds. When exposed to ionizing radiation, like photon, electron and proton beams used in radiotherapy applications, some diacetylene crystals undergo a radical solid-state polymerization reaction,...
Polycrystalline monolayer graphene films grown by chemical vapor deposition were exposed to a low-pressure inductively-coupled plasma operated in a gaseous mixture of argon and diborane. Optical emission spectroscopy and plasma sampling mass spectrometry reveal high B2H6 fragmentation leading to significant populations of both boron and hydrogen species in the gas phase. X-ray photoelectron...
Level attraction describes a mode coalescence that can take place in driven open systems. It indicates a development of an instability region in the energy spectrum of the system bounded by exceptional points [1]. This regime has been recently reported in a number of experiments in driven dissipative cavity magnonic systems [2].
Here, we present a framework for describing the mode...
The identity of dark matter remains a mystery, despite decades of theorizing and detection efforts. This includes the mechanism for its primordial production, its interactions of with itself and with visible matter, and the very nature of dark matter, which could range from a Bose-Einstein Condensate, to Black Holes, to a traditional particle. In this talk I will discuss new directions for...
: Plasma Immersion Ion Implantation (PIII) is a versatile material processing technique [1,2] with many applications in semiconductor doping, micro- and nanofabrication [3], as well as the surface modification of metals for improved resistance against wear and corrosion. In PIII a solid target is immersed in plasma, and negative polarity high-voltage (typically 1-20 kV) are applied the...
This talk aims to give an example of how a degree in physics can lead to an interesting industrial career in optical sensor development. A broad understanding of different physical laws and behaviors (mechanics, thermodynamics, electromagnetics, optics), combined with a practical grounding in electronics, programming and machining, provides an ideal skill set for developing optical instruments...
The National Research Council is launching The Internet of Things: Quantum Sensors Challenge Program in 2021. This program has seven years of funding and aims to develop a disruptive generation of quantum sensors that are orders of magnitude better than sensors that exist today. The program is structured to encourage collaborative research projects between the NRC and researchers in...
Plasma immersion ion implantation (PIII) is a versatile tool in the field of materials processing, surface modification, and semiconductor manufacturing[1]. By immersing the target directly in the plasma, PIII boasts many advantages over its predecessor, conventional ion implantation, including a simpler design, faster throughput and more uniform implantation over irregular objects[4]. When a...
A worldwide search is underway for elastic scattering between massive dark matter and nuclei in underground laboratories. Asymmetric dark matter particles with masses above a few GeV could easily be captured in stars via the same process. It has long been known that this can lead to observational consequences, as the weakly-interacting particles act as an efficient heat conductor. This can...
Elementary excitations in highly entangled states such as quantum spin liquids may exhibit exotic statistics, different from those obeyed by fundamental bosons and fermions. Excitations called non-Abelian anyons are predicted to exist in a Kitaev spin liquid - the ground state of an exactly solvable model proposed by Kitaev. Material realization of the spin liquid has been the subject of...
In less than five years, the field of gravitational wave astronomy has grown from a groundbreaking first discovery to revealing new populations of stellar remnants through distant cosmic collisions. I'll summarize recent results from LIGO-Virgo and their wide-reaching implications, give an overview of the instrumentation of the current Advanced LIGO detectors, and discuss prospects for the...
In the distant future we expect to be using large-scale, nearly perfect quantum computers that aid in drug discovery, break RSA encryption, and outperform supercomputers in certain machine learning tasks. Today we have access to small quantum computers afflicted by noise and error. Somewhere between these two extremes lies a momentous event for the field known as quantum advantage: solving a...
Objective: Dose distribution index (DDI) is a dose-volume parameter used in the treatment planning evaluation. DDI provides the dosimetric estimates on the target coverage, sparings of all organs-at-risk and remaining healthy tissue in the treated organ in a single parameter. In this study, the DDI value was predicted by machine learning model using different algorithms.
Methods: The DDI...
Objective: We built a RT Bot, a chatbot with characterization for the patient, general public and radiation staff to provide educational information regarding radiotherapy using the artificial intelligence. The Bot was personalized by machine learning to detect the user’s temperament and intent in order to provide the best guidance to the user with a human-like response.
Methods: The Bot...
Purpose: A quantitative measure of delivered ionizing radiation is recommended for quality assurance and quality control purposes for patients undergoing radiotherapy treatments. Current dosimeters are not well suited for direct measurements due to atomic composition and size limitations. We are developing a fiber optic probe dosimeter based on radiochromic material for in vivo dosimetry....
The diamond Nitrogen-Vacancy centre (NV-centre) is a defect which occurs in natural diamonds, and can also be introduced artificially. Due to screening effects, the NV-centre defect exhibits remarkably long spin coherence times. This means the diamond NV centre can be used for precision magnetometry, using Optically Detected Magnetic Resonance (ODMR) of the Zeeman splitting. This talk will...
This talk focuses on the responsibility of scientists to counter pseudo-scientific ideas in society, and reviews the factors that have led to a rise in popular anti-science sentiment. I will provide insights into how to communicate the ideas of science with the public, and I will give some examples of important environmental issues that are most commonly misconstrued by the general public,...
Very large neutrino telescopes are multipurpose instruments that can observe tens of thousands of neutrinos interact at energies well beyond those of man-made accelerators. This has made them unique experiments for studying neutrino properties and probing what might be beyond the Standard Model. Exotic neutrino oscillations, new interactions and new force mediators are among these topics. In...
The vast majority of dusty/complex plasma experiments have involved the suspension of charged, micron-sized particles in plasmas. The particles are suspended due to a delicate balance between gravitational and electrostatic forces. The addition of a magnetic field to these systems has a profound influence on both the surrounding plasma and the dusty plasma as the dynamics of first the...
Many important challenges in science and technology can be cast as optimization problems. When viewed in a statistical physics framework, these can be tackled by simulated annealing, where a gradual cooling procedure helps search for ground state solutions of a target Hamiltonian. While powerful, simulated annealing is known to have prohibitively slow sampling dynamics when the optimization...
$\mathrm{Mn}_3\mathrm{X}$ compounds in which the magnetic $\mathrm{Mn}$ atoms form AB-stacked kagome lattices have received a tremendous amount of attention since the observation of the anomalous Hall effect in $\mathrm{Mn}_3\mathrm{Ge}$ and $\mathrm{Mn}_3\mathrm{Sn}$. Although the magnetic ground state has been known for some time to be an inverse triangular structure with an induced in-plane...
New developments toward creating a working 2-way communication between brains and machines offer exciting possibilities, yet are often limited simply by the basic bio-compatibility of the materials employed in their construction. Traditional electrical engineering semiconductors and metals are often quite poor choices for use in a real living wet biological environment, and much recent effort...
We present a novel quantum multi-mode time bin interferometer that is suitable for a wide range of optical signals and capable of being used for free space quantum channels. Our design uses only reflective optics with curved mirrors providing the one-to-one imaging system necessary for a multi-mode interferometer. The curved mirrors are ideal since, unlike lenses, their focal length depends...
The Ce3+ pseudospin-1/2 degrees of freedom in the pyrochlore magnet Ce2Zr2O7 are known to possess dipole-octupole (DO) character, making it a candidate for novel quantum spin liquid (QSL) ground states at low temperatures. We report new heat capacity (CP) measurements on Ce2Zr2O7, which can be extrapolated to zero temperature to account for R·ln(2) entropy using a form appropriate to quantum...
The dependence of the mode-coupling instability threshold in two-dimensional complex plasma crystals is studied. It is shown that for a given microparticle suspension at a given discharge power there exist two thresholds in pressure. Above a specific pressure $p_\mathrm{max}$, the monolayer is always in the crystal phase. Below a specific pressure $p_\mathrm{min}$, the crystalline monolayer...
Single acceptor dopants in Si along with dangling bonds are enabling technologies for atomic scale charge and spin-based devices.[1] Additionally, recent advances in hydrogen lithography have enabled the patterning of quantum dot based circuit elements with atomic precision.[2] We engineered a single acceptor coupled to a dangling bond wire on highly doped p-type H-Si(100) and characterized...
Quantum dots embedded in photonic nanowires are highly efficient single photon generators. Integrating such sources on-chip offers enhanced stability and miniaturization; both of which are important in many applications involving quantum information processing. We demonstrate the efficient coupling of quantum light generated in a III-V photonic nanowire to a silicon-based photonic integrated...
I will review some important challenges for theoretical cosmology, focusing on the trans-Planckian problem for inflation and the anisotropy problem for matter bounce and ekpyrosis, and I will discuss some recent work exploring particular aspects of these problems.
Bilateral symmetry in animals commonly leads to a duality in peripheral sensory apparatus. For example, two eyes, as commonly found in most vertebrates, provide a mechanism to encode information such that subsequent neural processing can create stereoscopic perception. Further, two ears lateralized to the sides of the head are important for sound source localization, a key ecological...
Fixed-bias multi-needle Langmuir probes consisting of several cylindrical probes biased to different potentials can be used to measure plasma parameters on satellite without the need of sweeping bias voltages. Compared to a single Langmuir probe for which voltage is varied periodically in time, fixed bias probes enable measurement with a significantly higher sampling rate and, owing to the...
Despite their weak interactions, neutrinos can carry stupendous amounts of information about the cosmos, thanks to their small masses and large abundance. The highest-energy neutrinos can tell us about the largest particle accelerators in the Universe, and can probe energy scales larger than those available at the LHC. I review the ability of future neutrino telescopes including IceCube-Gen2,...
Optically active defects in solids---colour centres---are one of the most promising platforms for implementing quantum technologies. Their spin degrees of freedom serve as quantum memories that in some cases can operate at room temperature. Their control can be achieved with microwave spin control and resonant optical excitation but is hindered by the broadening of optical transitions from...
Among solid state quantum emitter systems, semiconductor quantum dots are particularly attractive due to their high radiative quantum efficiencies [1], their strong optical coupling enabling fast [2] and arbitrary [3] qubit rotations, and their tunable emission in the range of standard telecommunication wavelengths. For applications such as quantum light sources and quantum nodes, it is...
Control systems are vital in engineering, and machine learning is transforming data science; however, their basic constructs are expressed in terms of classical physics, which impedes generalizing to quantum control and quantum machine learning in a consistent way. We incorporate classical and quantum control and learning and their dependencies into a single conceptual framework. Then we...
The physics of heavy 5d transition metal oxides can be remarkably different from that of their lighter 3d counterparts. In particular, the presence of strong spin-orbit coupling (SOC) effects can lead to the formation of exotic ground states such as spin-orbital Mott insulators, topological insulators, Weyl semimetals, and quantum spin liquids. In materials with an edge-sharing octahedral...
In addition to being extremely sensitive sensors, nitrogen vacancies (NV) centers in diamond are an ideal showcase of quantum technologies as they work in ambient conditions. Experiments with NV centers usually involve a bulky optical system, together with a wide assortment of signal generators and samplers, which is challenging to synchronize together. Here, we perform quantum control...
Affiliation: University of Saskatchewan
Fusion and related plasma physics research enables the development of a new, safe and reliable, high-output fusion energy source. There are however multiple problems to address with fusion devices. One such problem is that of contaminating dust, produced by plasma wall interactions within the reactor.
Dust generation from Plasma Facing Components...
Recent unprecedented developments in astronomical observations have established the era of multi-messenger astronomy. Weakly interacting neutrinos play a fundamental role in the evolution of supernovae, neutron star mergers, and accretion disks around black holes. The byproducts of neutrino reactions with ejected matter as well as their direct detection provide extra insight about the physics...
I will argue why we need to remain objective about the physics of the early universe and explore different scenarios. In particular, I will present a cosmological bounce model based on Cuscuton gravity that does not have any ghosts or curvature instabilities. I will then discuss if Cuscuton bounce can provide an alternative to inflation for generating near scale-invariant scalar perturbations....
When you look at a picture, neurons are excited within your eyes and your brain. Those neurons' activation patterns reflect your perception of the stimulus, and can be measured in neurophysiology experiments. Importantly, these neuronal responses are profoundly shaped by visual experience. In this presentation, I will discuss the nature of the brain's visual representations, and the mechanisms...
For nearly a century, Langmuir probes have been used to infer plasma densities and temperatures from current characteristics. In practically all cases, these inferences are based on analytic expressions obtained theoretically. Despite their limitations, analytic expressions continue to be used because of their relative simplicity, and the fact that they can be used to construct fast inference...
We study an effective pseudo-spin model from microscopics for d$^2$ materials on various lattice geometries. It was found that the interplay between electron-electron interactions and spin-orbit coupling generates intriguing multipole-multipole interactions. These interactions give rise to various multipolar phases, which were identified using computational techniques such as classical Monte...
SBQuantum are building a Magnetic Intelligence Platform to extract additional information from magnetic fields. The platform uses nitrogen-vacancy diamond sensors to unlock the tensor information from the magnetic field before interpreting this data through a suite of proprietary algorithms for the detection and classification of magnetic anomalies. This presentation will dive through the...
Generating high-quality data (e.g. images or video) is one of the most exciting and challenging frontiers in unsupervised machine learning. Utilizing quantum computers in such tasks to potentially enhance conventional machine learning algorithms has emerged as a promising application, but poses big challenges due to the limited number of qubits and the level of gate noise in available devices....
This work considers the use of spherical segmented Langmuir probes as a means to measure ionospheric plasma flow velocities. This is done by carrying out three-dimensional kinetic self-consistent Particle in Cell (PIC) simulations to compute the response of a probe to space plasma under a range of space environment conditions of relevance to satellites in low Earth orbit (LEO) at low and mid...
Different theories of the very early universe that can explain our observations of the cosmic microwave background are presented. The current paradigm - inflationary cosmology - has received much attention, but it is not the only theoretically viable explanation; indeed, several alternative scenarios exist. It thus bares the question: how can we discriminate between the various theories, both...
The Scintillating Bubble Chamber (SBC) experiment is a novel multipurpose technique optimized for low-energy nuclear recoils detection. Two semi-identical detectors are under development by the collaboration, aimed at studying dark matter interactions (SBC-SNOLAB) and reactor CEvNS interactions (SBC-CEvNS). This talk will review the detector strategies and the feasibility studies of the weak...
Condensed matter systems admit topological collective excitations above a trivial ground state, an example being Chern insulators formed by Dirac bosons with a gap at finite energies. However, in contrast to electrons, there is no particle-number conservation law for collective excitations. This gives rise to particle number-nonconserving many-body interactions whose influence on...
In the weakly electric fish Eigenmannia (glass knifefish), high frequency (200-600Hz) electric organ discharge (EOD) is driven by high frequency cholinergic synaptic input onto the electrocytes at their electroplaques. Assuming periodic release of ACh into the cylindrical synaptic gap, we solve numerically a one dimensional reaction-diffusion model at 200Hz and 500Hz. The model included the...
Flow-through Z-pinches were first discovered over 50 years ago, manifesting themselves as a stable, pinch-like structure that persisted for 100 us in the Newton-Marshal gun experiments at LANL in the late 1960’s. Linear stability analysis performed by Uri Shumlak in the 1990’s showed that when dV_z/dr > 0.1 k V_A the kink mode could be stabilized in a Z-pinch plasma. Experimental work over the...
Ultra-weak light, known as biophotons, are emitted spontaneously by living organisms, but the origin, wavelength and the underlying mechanisms have not yet been clearly identified; although energy metabolic processes seem to be involved. Moreover, neurons can emit photons and there is strong experimental and theoretical evidence that myelinated axons can serve as photonic waveguides. Thus, it...
We argue that the usual magnetization $\vec{M}$, which represents a correlated property of 10$^{23}$ variables, but is summarized by a single variable, cannot diffuse; only the non-equilibrium spin accumulation magnetization $\vec{m}$, due to excitations, can diffuse. For transverse deviations from equilibrium this is consistent with work by Silsbee, Janossy, and Monod (1979), and by...
NEWS-G (New Experiments With Spheres-Gas) is a rare event search experiment using Spherical Proportional Counters (SPCs). Primarily designed for the direct detection of dark matter, this technology also has appealing features for Coherent Elastic Neutrino-Nucleus Scattering (CE$\nu$NS) studies. CE$\nu$NS is a process predicted by the standard model and can be used as a tool to probe new...
Quantum confinement and manipulation of charge carriers are critical for achieving devices practical for various quantum technologies such as quantum sensing. Atomically thin transition metal dichalcogenides (TMDCs) have attractive properties such as spin-valley locking, large spin-orbit coupling and high confinement energies which provide a promising platform for novel quantum technologies....
In microscopy, the imaging of light-sensitive materials has been a persistent problem, as the sample being studied may be altered or damaged by the illumination itself. Naturally, to overcome over-illuminating the sample, one can reduce the intensity of the classical light source; however, reducing the source intensity comes with a trade-off which affects noise and image quality. In recent...
Non-classical light sources are an important tool for many quantum information processing applications such as quantum key distribution and linear optical quantum computing. Sources based on semiconductor quantum dots offer close to ideal performance in terms of efficiency and single photon purity. However, emission rates are limited by the radiative lifetime of the excitonic complexes. This...
Energy loss in magnetic confinement fusion is dominated by plasma turbulence --- turbulent transport can surpass all other mechanisms by several orders of magnitude. Instability, driven by the Ion Temperature Gradient (ITG) mode is a key contributor to such turbulence, and is the topic of this work. Simulating such small-scale, $\mathcal{O}(\mathrm{mm})$, turbulence over an...
An overview of the latest results and Run 3 prospects for Heavy Neutrino searches at ATLAS will be discussed.
Steep thermal gradients in a magnetized plasma can induce a variety of spontaneous low frequency excitations such as drift-Alfven waves and vortices. We present results from basic experiments on heat transport in magnetized plasmas with multiple heat sources in close proximity [1]. The experiments were carried out at the upgraded Large Plasma Device (LAPD) operated by the Basic Plasma Science...
Presentation of the results of the EDI Survey.
The multiple interactions of light with biomolecules, cells and tissues enable established and emerging techniques and technologies used in cancer research and patient care. These approaches range from simple, point-of-care devices to complex, multifunctional platforms combined with complementary non-optical methods, including nanotechnologies, robotics, bioinformatics and machine learning....
Defect engineering plays an essential role in materials science and is of paramount importance in thin-film device fabrication. Novel experimental methods are needed to identify and quantify defects during film growth. The Debye temperature (DT) of a solid is a representation of the stiffness and so is sensitive to defect concentrations. The DT tends to decrease in the vicinity of the surface...
Frustrated magnetic materials and strongly correlated electron systems are a forefront of research in modern condensed matter physics and materials science. Despite almost three decades of investigations, the theoretical understanding of these fascinating systems remains incomplete. The most prominent theoretical frameworks used to tackle these systems take the form of an emergent gauge theory...
In this talk I will discuss how one may view four-dimensional de Sitter space as a coherent Glauber-Sudarshan state in string theory. I will also discuss why a de Sitter space cannot exist as a vacuum state in string theory.
The 12C+12C fusion reaction is one of the key reactions governing the evolution of massive stars as well as being critical to the physics underpinning various explosive astrophysical scenarios. Our understanding of the 12C+12C reaction rate in the Gamow window – the energy range relevant to the different astrophysical scenarios – is presently confused. This is due to the large number of...
Quantum computing is a rapidly growing field both in academia and industry. This is driving the need to expand traditional course offerings and degree programs to train the next generation of researchers and quantum scientists. Most programs have focused on graduate courses and research opportunities for students with a physics background. Laurier’s combination of physics and computer science...
When an interesting idea appears in natural science there is a good chance that someone else has already thought of it, independently, or will think of it if news does not travel fast enough. Sociologists recognize this as a phenomenon that has something to teach us about the nature of research in science. I will offer examples to be found in the discovery of the idea of the hot big bang cosmology.
Medical x-ray imaging has revolutionized modern medicine. A necessary and critical component of a medical x-ray imaging system is the x-ray detector. Over the past 50 years, x-ray detectors have evolved from film-screen systems, to computed radiographic cassettes, culminating in flat-panel digital x-ray detectors that directly capture image data during patient examination, bypassing the need...
Carbon monoxide (CO) has a bad reputation due to potential lethal consequences when inhaled at high concentrations in humans. However, at low doses CO exerts a broad spectrum of biological activities that results in a variety of beneficial actions including among others anti-inflammatory, vasodilatory, anti-apoptotic and anti-proliferative effects [1].
Plasma can generate CO from the...
In our presentation, we will offer an overview of aperture-type scanning near field optical microscopy (SNOM) – a family of nano-optical imaging techniques derived from scanning probe microscopy which are capable of subwavelength resolution, and the development of three dimensional (3D) SNOM methods undertaken by our group to locally image the distribution of the electromagnetic radiation in...
Perfectly T-linear resistivity is observed in a variety of strongly correlated metals close to a quantum critical point [1] and has been attributed to a scattering rate 1/τ of charge carriers that reaches the Planckian limit [2,3], with ℏ/𝜏 = α 𝑘𝐵𝑇 where α is of order unity. While this relationship is often inferred from simple estimates, a T-linear scattering rate has yet to be measured.
To...
Accreting neutron stars host a variety of astronomical observables which can be compared to model calculations to obtain dense matter constraints. However, key observables such as X-ray bursts and crust cooling are directly influenced by the structure of atomic nuclei involved in these processes. I will demonstrate the sensitivity of astrophysical models of accreting neutron star phenomena to...
The Belle II experiment at the SuperKEKB collider in Tsukuba, Japan began physics data taking in 2019. With a target integrated luminosity of 50 ab-1, Belle II aims to record a data sample that is roughly 40-100 times larger than its predecessors thus enabling some uniquely high-precision studies of b-quark, c-quark, and tau-lepton physics. The experiment provides an interesting environment...
I will present my group’s recent efforts to combine atomic ensembles with nanophotonic structures. I will describe our experiment in which photons emitted by a quantum dot embedded in a semiconductor nanowire are sent into an ensemble of laser-cooled caesium atoms confined inside a hollow-core photonic-crystal fibre to realize photon storage and single-photon wavelength conversion....
I will discuss different notions of nonrelativistic strings and their target space geometries. The first example comes from a self-contained corner of string theory dubbed nonrelativistic string theory, which is closely related to string theory in the discrete light-cone quantization. The appropriate spacetime geometry for nonrelativistic string theory is a stringy generalization of...
A method to calculate the one-body Green's function for ground states of correlated electron materials is formulated by extending the variational Monte Carlo (VMC) method [1]. We apply the method to larger-sized Hubbard model on the square lattice correctly reproduces the Mott insulating behaviour at half-filling and gap structures of d-wave superconducting state on the 12 by 12 cluster of the...
Blister formation occurs when a laser pulse is focussed through a transparent substrate onto a coated polymer thin film. A pocket of expanding vapor is formed beneath the film, which pushes the film upward locally. This process has been used for Laser-Induced Forward Transfer (LIFT) of materials. Most studies of blister formation and blister-based LIFT use linear absorption of nanosecond or...
I will review the recently discovered ’t Hooft anomalies involving higher-form symmetries and discuss some of their implications for the dynamics of vector-like gauge theories.
Currently, plasmonic nanofibers doped with semiconductor quantum dots, organic dye quantum emitters (QEs), and metallic nanoparticles (MNPs) have attracted much attention due to their wide range of applications including waveguides, light-sources, and optical sensors. These nanofibers doped with QEs and MNPs have been fabricated using a variety of metals and emitters. For example, Hu et al....
Effective field theories (EFT) are widely used to parameterize long-distance effects of unknown short-distance dynamics or possible new heavy particles. It is known that EFT parameters are not entirely arbitrary, and in particular must obey positivity constraints if causality and unitarity are satisfied at all scales. We systematically explore those constraints from the perspective of 2 to 2...
The morphology of ice formed under flowing liquid water is a challenging
free-boundary problem. A common case in nature is the formation of icicles,
which grow as liquid water flows down the surface, freezing as it descends.
Theories of icicle growth have always assumed a thin liquid coat over the
entire icicle's surface. These theories predict the growth in length and mean
diameter...
During the last decade, translational and rotational symmetry-breaking phases — density wave order and electronic nematicity — have been established as generic and distinct features of many correlated electron systems, including pnictide and cuprate superconductors. However, in cuprates, the relationship between these electronic symmetry-breaking phases and the enigmatic pseudogap phase...
I describe the first investigation of the holographic complexity conjectures for rotating black holes. Exploiting a simplification that occurs for equal-spinning odd dimensional black holes, I demonstrate a relationship between the complexity of formation and the thermodynamic volume associated with the black hole. This result suggests that it is thermodynamic volume and not entropy that...
Liquid-phase exfoliation (LPE) is a low-cost and scalable technique for producing a wide range of van der Waals nanomaterials that can be incorporated into existing laboratory sample and industrial material production. Liquid-phase exfoliated nanomaterials have the potential to produce devices quickly and at low-cost, with colloidal dispersions easily adaptable to existing production methods....
During neutron star black hole collision events, 20 percent of the binding energy is released in the form of neutrinos. These mergers form a black hole with a disk of matter accreting into it. The neutrino signal observed on earth will depend on where the neutrinos become free from the system; this is called the neutrino surface. The neutrino surface can be determined based on hydrodynamic...
Belle II is a B factory experiment for the SuperKEKb electron-positron collider located at the KEK laboratory in Tsukuba, Japan, operating near the Upsilon(4S) resonance, at an energy of 10.58 GeV. In this talk I will discuss our analysis searching for the ultra-rare charged lepton flavour violating (CLFV) decay $B^+ \to K^+ \tau$ e. This decay is far below experimental sensitivity if we...
Non-thermal plasma (NTP) is being increasingly considered for its many medical applications. Even though NTP comprises physical factors such as the electric field and charged particles, NTP is mostly recognized to induce biological responses through its production and delivery of reactive species such as reactive oxygen and nitrogen species (RONS). Precise tuning of RONS is an important issue...
s-process nucleosynthesis can be influenced by so-called 'light element neutron poisons', which absorb free neutrons before they can capture onto iron-peak seed nuclei. The 16O(n,gamma) reaction is one such neutron poison reaction. However, free neutrons can then be released back into the star via 17O(alpha,n)20Ne. The ratio of the neutron and gamma outgoing channels in 17O + alpha reactions...
Understanding and controlling the properties of 2D materials to our advantage can be contemplated with the development of experimental tools to probe and manipulate electrons and their interactions at the atomic scale. In this talk, I will present scanning tunnelling microscopy and spectroscopy experiments aimed at: elucidating the nature of atomic-scale defects in 2D materials [1],...
For almost five decades, Magnetic Resonance Imaging (MRI) has been on a monotonic technological progression towards higher and higher magnetic field strength. This is largely due to the fact that, as any physicist will tell you, nuclear magnetization and therefore MR signal strength scales with the applied field strength. Why then go backwards to a low magnetic field to explore advanced...
Ability to control spin is important for probing many spin related phenomena in the field of spintronics. Spin-orbit torque is an important example in which spin flows across magnetic interface and helps to control magnetization dynamics. As spin can be carried by electrons, spin-triplet pairs, Bogoliubov quasiparticles, magnons, spin superfluids, spinons, etc., studies of spin currents can...
Prior research has found limitations in how students reason about uncertainty and measurement in introductory courses, with many students thinking point-like (a single measurement could be the true value) rather than set-like (a set of measurements estimate the parameter). Motivated by the question, "How does that intro-level reasoning influence student thinking about quantum mechanical...
The Belle II experiment is a next-generation $B$-factory experiment located at the SuperKEKB $e^+e^-$ collider, with the focus on examining the decays of $B\bar{B}$ meson pairs. The Belle II experiment started data taking in March 2019. It has since reached a world-record instantaneous luminosity of $2.4\times10^{34}{\rm cm^{-2}s^{-1}}$, and has accumulated a total of $90.0\,{\rm fb^{-1}}$ to...
A long-standing goal of hadron physics has been to understand how the quark and gluon degrees of freedom that are present in the fundamental QCD Lagrangian manifest themselves in the spectrum of hadrons.
The GlueX experiment at Jefferson lab contributes to the global spectroscopy program using 8-9~GeV linearly polarized photons. This experiment focuses on the exploration of the light-quark...
MRI provides exquisitely detailed images of brain and spinal cord anatomy and pathology. MR images are multi-planar, radiation free and have a greater sensitivity and specificity than either CT or ultrasonography. Although an engineering challenge, the placement of MRI systems in the operating room will revolutionize neurosurgical care. Surgical navigation was repeatedly updated by iMR images...
Nucleosynthesis in the neutrino-driven wind of core-collapse supernovae has gained in popularity in recent years and it is thought to produce light neutron-deficient nuclei with $A\leq110$ via the $\nu p$-process. However, this scenario exhibits uncertainties related to the explosion dynamics and the underlying nuclear physics input. The $^7$Be($\alpha,\gamma$)$^{11}$C reaction has been shown...
Interactions between localized, unpaired spins and delocalized electrons play a key role in a range of phenomena, including the Kondo effect, RKKY interactions and high Tc superconductivity. A number of recent studies have explored such interaction using hybrid systems combining 1) molecules with metal ions which contribute unpaired, localized spins and 2) deposited Au films which contribute...
Increasing sensitivity in rare event search experiments requires the development and characterization of novel background rejection techniques and technologies. To aid in the development of these techniques for future liquid Argon (LAr) detectors, an R&D detector “Argon-1” has been commissioned at Carleton University. Argon-1 is a single phase 35 kg LAr test detector, employing 65+ channels...
Nuclear 2$\gamma$ decay is a second-order electromagnetic interaction wherein two photons are simultaneously emitted during a nuclear de-excitation. This transition is uniquely sensitive to the electromagnetic polarizability of the nucleus and has been studied in non-competitive cases for $0_2^+ \longrightarrow 0_1^+$ transitions between the first excited and ground states of even-even nuclei....
We develop the embedding space formalism and determine the full operator product expansion relevant to conformal field theories in arbitrary spacetime dimensions. With the operator product expansion, we then show how to compute generic conformal blocks for correlation functions with any number of quasi-primary operators in arbitrary irreducible representations of the Lorentz group. ...
The success of non-thermal plasmas in a broad range of applications in materials, medicine, and for the environment lies in their high reactivity at non-equilibrium conditions [1]. Cold atmospheric pressure plasma sources operated with air or noble gases allow plasma treatment at ambient conditions. Plasmas can thus induce novel chemistry into sensitive environments such as nano-scaled...
Inhaled hyperpolarized gas lung MRI was proven to be useful for the observation and treatment planning of several pulmonary diseases including chronic obstructive pulmonary disease, asthma, COVID-19 and lung cancer. The combined economic burden of COPD and asthma in Canada, Ontario being $5.7 billion (2011). While these statistics are alarming, they don’t fully reflect the impact on economic...
Geometrically frustrated systems have an inherent incompatibility between the lattice geometry and the magnetic interactions, resulting in macroscopically degenerate ground-state manifolds. The single-ion anisotropy in these systems gives rise to unusual noncollinear spin textures [1,2], such as a spin ice state that hosts emergent quasiparticle excitations equivalent to magnetic monopoles. ...
I will describe my experience and the students' feedback in the course "Introduction to Quantum Computing" for second year students at University of Victoria. The class was composed by physics, astronomy, mathematics, computer science, electrical, mechanical, and software engineering majors. The course's only pre-requisite was first-year linear algebra, and most of the students had never had...
The proposed nEXO experiment is searching for neutrinoless double beta decay (0νββ) in 136-Xe in a tonne-scale liquid xenon time-projection chamber (TPC). If observed, 0νββ will reveal the Majorana nature of neutrinos and violation of lepton number conservation. Searches for such extremely rare events require excellent background suppression and rejection methods to achieve high sensitivities....
Spectral purity in laser emission is key for several applications such as remote sensing, non-linear optics and laser spectroscopy. However, producing single mode emission at high power in free-space, standing-wave resonators is challenging. Nanostructured laser mirrors can be used to achieve that in compact microchip monolithic laser resonators without using any additional intra-cavity...
The observation of neutral long-lived particles (LLPs) at the LHC would reveal novel physics beyond the Standard Model. LLP signatures are well motivated and can appear in many theoretical constructs that address the Hierarchy Problem, Dark Matter, Neutrino Masses and the Baryon Asymmetry of the Universe. With the current experimental program at colliders, no search strategy will be able to...
We investigate the electronic dispersion and transport properties of graphene/WSe$_{2}$ heterostructures in the presence of a proximity-induced spin-orbit coupling $\lambda_{v}$, sublattice potential $\Delta$, and an off-resonant circularly polarized light of frequency $\Omega$ and effective energy term $\Delta_{\Omega}$. Using a low-energy effective Hamiltonian we find that the interplay...
The solid polymer light-emitting electrochemical cell (PLEC) possesses a polymer homojunction that is reminiscent of a conventional p-n junction but also exhibits distinct features that are profoundly intriguing. The PLEC junction is formed under bias when the propagating p- and n-doping fronts in the semiconducting polymer make contact. The PLEC junction can be immobilized by cooling after...
Through the AdS/CFT correspondence, properties of a quantum field theory are equivalent to geometric quantities in the bulk of anti-de Sitter spacetime. The complexity of the QFT state at some time is conjectured to be either the volume of a slice through AdS or the action on a patch of AdS. We evaluate both types of complexity during the gravitational collapse of a scalar field in AdS, which...
Double-quantum (DQ) coherence transfers in two-pulse DQ and five-pulse DQM (double quantum modulation) EPR pulse sequences, utilized for orientation selectivity and distance measurements in biological systems using nitroxide biradicals, are investigated. Analytical expressions, along with numerical algorithms, for EPR signals are given in full details. It is shown, in general, that a finite...
Supercontinuum generation in optical fiber is the result of an interplay between multiple nonlinear processes. Simulations to reproduce experimental observations are well documented: a differential equation known as the generalized nonlinear Schrödinger equation (GNLSE) is solved to determine the effect of propagation on the spectral and temporal profiles of the slowly-varying amplitude of a...
The Cryogenic Underground TEst facility (CUTE), located approximately 2 kilometers underground at SNOLAB, has been operational since 2019. It provides a well-shielded, low-background environment, ideal for testing cryogenic detectors for rare event searches. The primary focus of CUTE is to test detectors in preparation for their use in the Super Cryogenic Dark Matter Search (SuperCDMS)...
Nanoscale sensors are widely used in industrial, environmental, and healthcare applications. The performance of chemical sensors depends on the host materials properties; low dimensional materials, e.g. graphene or carbon nanotubes, can be used as host materials to detect chemicals in the environment. These materials provide wide surface area per unit of volume capable of hosting...
The TUCAN collaboration is preparing to make a precision measurement of the neutron's permanent electric dipole moment, $d_n$, with a sensitivity of $\sigma(d_n)\leq10^{-27}e\cdot cm$. To reach the goal sensitivity it is required to have highly uniform and well understood magnetic fields in the measurement cells. With ambient magnetic fields on order of hundreds of $\mu \rm T$, passive...
The TUCAN collaboration is developing a new source of Ultracold neutrons (UCN) that will be used in a neutron Electric Dipole Moment (nEDM) experiment, with a goal sensitivity of 10^(-27) e*cm which is 10 times more precise than the best measurement to date. UCNs are neutrons with energies below 300 neV, that are travelling with speeds less than 30 km/h. In order to carry out a world-leading...
Theories of Quantum Gravity predict a minimum measurable length and a corresponding modification of the Heisenberg Uncertainty Principle to the so-called Generalized Uncertainty Principle (GUP). However, this modification is non-relativistic, making it unclear whether the minimum length is Lorentz invariant. We formulate a Relativistic Generalized Uncertainty Principle, resulting ...
The basic structure of quantum field theory that is used to describe the Standard Model of fundamental interactions of nature is usually formulated for zero temperature. However, the effects of temperature are extremely important for understanding a number of physical processes such as the electro-weak phase transition and quark-gluon plasma. Thermal field theory is the extension of quantum...
Next generation wireless communication technologies will rely on techniques able to rapidly change the properties of an optical filter in the far-infrared region. Here we demonstrate ultrafast modulation of a metasurface’s transmission spectrum containing a resonance around the optical frequency of 1 terahertz (THz). The metasurface consists of an array of sub-wavelength gold crosses deposited...
In this work, we present a method based on deep learning (DL) to predict the structure of amorphous silicon (a-Si). The accuracy of our approach is validated through training networks to estimate the potential energy. Two architectures, multilayer perceptron (MLP) and convolutional neural network (CNN), have been examined for this purpose.
The models have been trained on a dataset generated...
The rare $K^+ \to \pi^+ \nu \overline{\nu}$ decay is an ideal probe for exploring physics beyond the Standard Model (BSM) at very high energy scales. This loop-dominated weak decay is heavily suppressed in the SM with a predicted branching ratio (BR) of $\left(8.4 \pm 1.0\right) \times 10^{-11}$.
The NA62 experiment at the CERN SPS is designed to study precisely the $K^+ \to \pi^+ \nu...
The potential breakdown of the notion of a metric at high energy scales could imply the existence of a fundamental minimal length scale below which distances cannot be resolved. One approach to realizing this minimum length scale is construct a quantum field theory with a bandlimit on the field. We report on an investigation of the effects of imposing a field bandlimit on a curved and compact...
Trapped ions are a leading platform for noisy intermediate-scale quantum (NISQ) computing with high gate fidelities, long coherence times, and natural long range ion-ion interactions. QuantumION is a project which aims to scale trapped ion quantum computing to 16 Ba+ qubits while providing an open-access resource to the whole research community. High fidelity control over each ion is crucial...
Hyper-K will be a next-generation long-baseline neutrino experiment in Japan with the main goal of measuring the neutrino flavour mixing parameters and discovering CP violation in the neutrino sector. Its detector complex will benefit from the construction of the Intermediate Water Cherenkov Detector (IWCD). The IWCD will measure the un-oscillated neutrino flux at different off-axis angles,...
We report on the development of a multi-element ion source for calibration of a multi-reflection time of flight mass spectrometer. A laser ablation ion source (LAS) has been developed that can deliver specific, diverse species of ions from multi-element targets. It has been demonstrated that different target materials may be selectively ablated with a spatial resolution lower than 100𝜇m. Ion...
It is an ongoing challenge to engineer setups in which Majorana zero modes at the ends of one-dimensional topological superconductor are well isolated which is the essence of topological protection. Recent developments have indicated that periodic deriving of a system can dynamically induce symmetries that its static counterpart does not possess [1]. We further develop the original protocol...
I will discuss two time-dependent models of systems relevant to the cryogenic function of TRIUMF Ultra-Cold Advanced Neutron (TUCAN) source. The first is a natural circulation system (thermosyphon) which cools the LD$_2$ moderator. The moderator experiences a heat load of 60~W for the design proton beam current of 40~$\mu$A, and is cooled to 20~K using a distant cryocooler at higher...
Non-thermal plasmas produced by nanosecond discharges is a novel field of plasma physics that have huge interest for medical physics or in liquid treatments due to their high reactivity. Although this field is under investigation since more than one decade, our understanding of the fundamental mechanisms is still at an embryonic level. Moreover, when such a plasma is coupled with a solid or...
Flat band systems are becoming popular due to special properties. For instance, the strong correlation of electrons leads to realization of unconventional superconductivity [1]. Typically, such bands are only approximately flat and are engineered by fine tuning Vanderwaal’s structures. Here we consider Kagome and Lieb lattices with perfectly flat bands. However, at some points in the Brillouin...
As dark matter searches aim to achieve lower energy thresholds, it is important to understand the behaviour of the detectors in these new regimes. Light-emitting diodes (LEDs) offer a simple and flexible source of photons with energy ranges from 0.3 eV (mid-infrared) to 5 eV (near ultraviolet). Prototype cryogenic silicon detectors developed by the SuperCDMS collaboration have been able to...
Low-energy precision tests of electro-weak physics keep playing an essential role in the search for new physics beyond the Standard Model. Atomic parity violation (APV) experiments measure the strength of highly forbidden atomic transitions induced by the parity violating (PV) exchange of Z bosons between electrons and quarks in heavy atoms. APV is also sensitive to additional interactions...
Physics is the most fundamental of sciences, so learning it can be a challenge, especially online. However, a fully-online asynchronous delivery mode can offer some advantages, especially for quickly-developing fields such as subatomic physics and astrophysics, whose active research communities often offer extensive educational resources online. Asynchronous online delivery also allows for...
There is strong evidence that some states in $^{10}$Be exhibit a molecular-like $\alpha$:2n:$\alpha$ configuration. Based on theoretical studies, it appears that the $6.179$ MeV 0$^{+}$ state in $^{10}$Be has a pronounced $\alpha$:2n:$\alpha$ configuration with an $\alpha$-$\alpha$ inter-distance of $3.55$ fm [Itagaki and Okabe, (2000)]. This is 1.8 times more than the corresponding value for...
Accurately targeting specific regions of interest in the brain is pivotal for the success of neurosurgical procedures. For example, the outcome of brain tumor resection is improved dramatically when surgeons are better able to define surgical borders. Interventional MRI (iMRI) helps reduce the risk of damaging critical areas of the brain and makes it possible to confirm a successful resection...
With the increasing complexity of quantum devices, the ability to connect non-neighbouring qubits is critical. Flying spin qubits present one solution to connect quantum gates at remote points in a single device. While the coherent transport of spins using moving potential dots defined by a surface acoustic wave (SAW) has been previously shown, we demonstrate the ability to gate the...
Transitions between fractionalized and conventional quantum phases of matter in 2+1 dimensions are conceptually best understood within the framework of parton gauge theories, whereby the confinement of fractionalized excitations and spontaneous breaking of global symmetries in conventional phases is argued to result from the proliferation of gauge monopoles/instantons. To complement recent...
As a part of the Phase-1 upgrade to the ATLAS muon spectrometer, Canada has taken a leading role in the construction, testing, and commissioning of small-strip Thin Gap Chambers or sTGCs, one of two detector technologies to be used in the ATLAS New Small Wheel. This presentation will detail the process in which sTGCs are built to their integration into the ATLAS detector. A focus will be given...
Magnetic resonance imaging (MRI) is a powerful non-invasive imaging technique with high resolution and excellent soft tissue contrast. However, access to MRI is limited by the high instrument cost and high maintenance cost. Current scanners cannot be easily relocated because of their size and weight. A low cost, portable scanner will enable point-of-care diagnosis as well as other industrial...
Phytoglycogen is a natural polysaccharide produced in sweet corn in the form of compact, 42 nm diameter glucose-based nanoparticles. Its highly branched, dendritic structure leads to interesting and useful properties that make the particles ideal as unique additives in personal care, nutrition and biomedical formulations. The properties of phytoglycogen can be altered through chemical...
Magnetic resonance imaging (MRI) is an imaging modality that offers superior soft tissue contrast without ionizing radiation. MRI requires a static magnetic field and a radiofrequency (RF) magnetic field. The static magnetic field is usually provided by a superconducting magnet, where the high cost limits its accessibility. A portable magnetic resonance device based on a permanent magnet is...
This presentation is based on a subset of data from a doctoral project on Physics Education Research (PER) in Canada. Current data describing the landscape of PER in Canada will be shared, offering a characterization of Canadian PER and the people who conduct it. The aim of the presentation is to increase the physics and PER community’s knowledge and understanding of this field beyond the...
Plasma-liquid systems are significantly investigated due to their high potential in the production of various nanomaterials. In addition to relatively high efficiency and simplified infrastructure, they are ecologic and do not have any risk during handling as they are confined in solution. In this paper, we develop a novel plasma-liquid technique to produce nanoparticles. Indeed, spark...
The Canadian Light Source (CLS) is considering a linear accelerator (LINAC) upgrade. As a result, the radio frequency (RF) structure in the downstream Energy Compression System (ECS) needs to be redesigned. In this paper, we describe the design process followed to determine the geometry of the RF structure cells and coupler. Wakefield simulation results are also presented. The wakefields and...
Hydrogen terminated silicon has seen a recent resurgence in popularity due to several works demonstrating its use for ultra-dense memory, atomic electronics, and quantum devices. On this surface, individual hydrogen atoms can be removed with atomic precision through STM pulses, leaving a dangling bond (DB) behind. DBs are quantum dot-like entities that can hold either 0, 1, or 2 electrons,...
Laser-induced breakdown spectroscopy (LIBS) is a laser-based spectrochemical technique that allows a near-instantaneous measurement of the elemental composition of a target by making time-resolved spectroscopic analyses of laser-induced ablation plasmas. Utilizing nanosecond laser pulses and a broadband high-resolu