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
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
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
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
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
Accelerator Mass Spectrometry (AMS) provides high sensitivity measurements (typically at or below 1 part in
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
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
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
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,
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
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 ~
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...
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
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
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
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
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,
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
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
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
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
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
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,
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
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
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
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-resolution Echelle spectrometer, high signal-to-noise optical emission spectra can be...
To allow for precision measurements of neutrino interactions in water Cherenkov neutrino detectors, reducing the position uncertainty on the photomultiplier tubes (PMTs) and calibration sources is necessary. This can be achieved with the photogrammetry technique. Detected PMTs in images of the detectors can be used to reconstruct a 3D model of their positions. This photogrammetry technique is...
Trapped ions can offer a functional platform for quantum simulation of many-body Hamiltonians modeled by spin-systems. Programmable, arbitrary and precise control over each ion is required in order to tune ion-ion interactions, which translate to diverse parameters of the system under study. Current technologies suffer from scalability issues to large ion chains, and from ``cross-talk'' due to...
The ability to image magnetodynamics has proved key to the advancement of spintronics technology [1]. As technological size scales reduce and speeds increase, there is a need to provide commensurate advancement in experimental tools to image magnetodynamics down to the atomic scale with ultrafast time resolution. In pursuit of this goal, we are developing a custom designed scanning tunneling...
We are developing a time-reversal breaking test in radiative
A key feature of third-generation light sources is their small vertical opening angle, which is difficult to measure experimentally. To reconstruct the vertical phase space, one can scan the beam’s position using X-ray synchrotron radiation (XSR) and a pinhole camera. The XSR diagnostic beamline, operational in the wavelength region of
Development of portable X-ray fluorescence devices has made it easier to quickly assess trace elements such as zinc in human tissue. Zinc deficiency can have serious implications on growth and development of the human body. From recent studies zinc content in nail clippings has been suggested to be an effective biomarker for zinc status. In this study, a simulation approach was used to...
Simple Measurement for Field Reconstruction
The temporal resolution of pump-probe experiments is determined by the duration of the excitation and measurement pulses. A major constraint on femtosecond (
The Light-only Liquid Xenon experiment aims to investigate scintillation and Cherenkov emission in Liquid Xenon (LXe). This is a small experiment set up consisting of 24 Hamamatsu Silicon Photomultipliers (SiPM), giving a total of 96 channels arranged in an octagonal cylinder. 92 of these channels are covered with 225 nm high pass filters which help measure Cherenkov and VUV scintillation...
First-semester physics labs typically aim to confirm and mirror relationships explored in the lectures. Often using computer-interfaced equipment to measure physical variables, students investigate relationships with time or other variables. We took our move to online delivery in the pandemic as an opportunity to re-think physics labs. We report here a suite of remotely delivered labs...
Recently, it was observed that under high pressure (p > 10Pa), nanoparticles could be created using sputtering magnetron discharges. Although this device has been widely studied at low gas pressure (p < 0.1Pa) for its industrial application such as thin film coating, there is no plasma model at the fairly high pressure range. The study of physical mechanism driving the transport of these...
Exact diagonalization is a powerful method to analyze a crystal system. In our research, we apply the exact diagonlization method on 16 site spin 1/2 Pyrochlore system. The Hamiltonian of this system can be expressed as a 65536 times 65536 matrix, then we use point group D_3 and FCC translational group to block diagonalise this matrix. Finally, we apply Lapack subroutine to get the eigenvalues...
Recently, there has been an increasing interest in the study of optical/microwave cavity-confined photon-magnon interaction due to their potential applications in quantum information processing and spintronics [1,2]. In those studies, a number of unique features have been observed at frequencies in the GHz range. On the other hand, less is known about the dynamics of...
The Canadian Light Source (CLS) synchrotron uses four fast kicker magnets to inject electrons into the storage ring from a 2.9 GeV booster ring. The injection occurs over several turns of the stored beam, which is also perturbed by the injection kickers. The resultant oscillations of the stored beam can negatively affect the quality of beamline experiments, so it is desirable to implement an...
Quantum computing requires the ability to prepare and manipulate arbitrary quantum states and read out results. Cold atom systems are a proven and highly versatile platform for the study of quantum computing and other aspects of quantum physics. They have been used to develop quantum memories, to study adiabatic quantum computing, and for quantum simulation.
In this work, we explore a...
The observed gender gap in physics testing is a problem which plagues physics education. Many studies in universities across North America show that female students consistently perform worse than male students on written examinations and concept inventories, though the size of this performance gap varies from study to study. In some cases, this gender gap in performance has been linked...
The field of nonlinear acousto-elastic behaviour in materials such as rocks is an area of active research, applicable to phenomena such as earthquakes or material fatigue. This nonlinearity arises from the rock microstructure, notably through cracks, and appears in the form of a nonlinear relation between the stress and strain fields within the rock. We study how this nonlinearity manifests...
We present our simple and cost-efficient setup for real-time monitoring of substrate thickness in plasma etching/deposition processes. Thin film interference occurs as light from the plasma passes through the substrate material, by observing the cycles of peaks and troughs in the intensity, the rate of etching/deposition was obtained.
Geometrical frustration arises in systems whose structures support multiple degenerate ground states. Artificial spin ice (ASI), has been built in diverse configurations which allows us to control frustration by experimentally tuning suitable parameters[1]. We present computational results on ASI systems consisting
of planar arrays of nanosized elongated ferromagnetic islands where...
We demonstrate that dark matter heating of gas clouds, hundreds of parsecs from the Milky Way Galactic Center, provides a powerful new test of dark sector interactions. As an example, we constrain ultralight dark photon dark matter, which requires a simple extension of the Standard Model (SM) by a U(1) gauge group. We place new bounds on ultralight dark photon dark matter for m ≤ 10^10 eV. An...
The DC gas discharge is a non-thermal laboratory plasma that is initiated by an applied electric field. It serves as a useful apparatus for studying fundamental phenomena in plasma physics and has found several applications in materials science and engineering. In contrast to thermally ionized plasma, the distribution function of a gas discharge deviates from Maxwellian at low pressures. It is...
Sea spray icing is created by wind/wave-induced spray in harsh arctic and antarctic environments. It is reported that sea spray icing causes hazardous conditions and operational problems for vessels and offshore structures. Nuclear Magnetic Resonance (NMR) is a powerful tool that can provide information about local environment, diffusion, and structure of a sample containing NMR-sensitive...
The connection between quantum entanglement and classical chaos has puzzled physicists for decades. To understand chaos in the quantum context, it is necessary to explore signatures of chaos in the deep quantum regime, where the quantum-classical correspondence cannot be invoked. A common approach is to study the quantum kicked top, which is a finite-dimensional quantum system that displays...
In the past few decades, scientists discovered that TiO2 was capable of purifying polluted water without any addition of strong oxidants. Active hydroxyl radicals can be produced through photodegradation process when TiO2 is illuminated under water, and such process is viewed as a favorable method for on-site decomposition of organic compounds. However, the main drawback of this process...
Bulk spinel vanadate crystals are structurally cubic and ferrimagnetic, with biaxial anisotropy along the cubic axes. However, for thin film Cobalt Vanadate, an orthorhombic crystal structure leads to very different and stronger magnetic anisotropies. Data from torque magnetometry shows a uniaxial anisotropy with the magnetic easy axis shifting from out-of-plane at high temperatures, to...
In the search for particle dark matter (DM), the most prominent model is the Weakly Interacting Massive Particle (WIMP). Should particle DM have some weak interaction with baryonic matter, the DM would interact with the matter found in the Sun and other massive bodies. When the DM scatters to velocities below the local escape velocity, this results in gravitational capture and subsequent...
Introductory physics courses are required at McMaster for students in a pure physics stream, engineering stream, or life sciences stream. The background preparation of these students, as well as their attitudes towards the course, can vary greatly. There lies huge importance in identifying topics and aspects of introductory physics courses that students enjoy and find challenging as a key...
RATIONALE: Hyperpolarized gas MRI is a powerful tool to track lung progression using biomarkers (ADC and mean linear intercept estimate (Lm)). Sometimes, longitudinal observations can lead to problematic values, as the disease progression can lead to increasing unventilated lung areas, which likely excludes the largest3 ADC/Lm values. We hypothesize that this morphometry method can provide an...
The Transverse Feedback system at the Canadian Light Source can identify, categorize, and mitigate against periodic instabilities that arise in the storage ring beam. By quickly opening and closing the feedback loop, previously mitigated instabilities will be allowed to grow briefly before being damped by the system. The resulting growth in the beam oscillation amplitude curve can be analyzed...
Understanding the physical limitations and trade-offs related to suppressing fluctuations in stochastic cellular processes is of great importance for systems and synthetic biology applications. We show that a generic class of complex formation processes in which two subunits associate to form a complex is constrained by a trade-off between the subunit fluctuations and the efficiency of complex...
The discovery of time-reversal symmetry(TRS) breaking in elemental Re has ignited fresh interest in the Re based superconductors. The recent studies show that role of Re concentration and crystal symmetry is crucial in understanding the unconventional superconductivity of these compounds. Therefore, we studied two Re-based superconductors Re
Cherenkov radiation plays a crucial role in particle physics experiments.
This is of particular importance in water-filled neutrino detectors, where electron neutrinos are observed through the Cherenkov radiation of ultra-relativistic secondary particles created in the detector's volume. Modern simulation methods of the process that describe Cherenkov emission assume coherence of the...
Camera trapping is widely used in different ecological studies and is particularly important for remote locations and extreme environments. However, due to certain optical challenges of adapting this approach to small rodents, combined with the logistical and environmental issues, it was not possible to use camera traps for subnivean observation during the arctic winter before. The frost...
Golnaz Azodi and James Stotz
Queen’s University, Kingston, Ontario, Canada
A piezoelectric substrate is key for generating surface acoustic waves. The high electromechanical coupling factor of Zinc Oxide (ZnO) makes it a suitable material for this purpose. Among various techniques, we use physical vapour deposition (PVD) to obtain a uniform and well-orientated film. In this study, we...
Effect of Lung Surfactant Protein B Fragment, SP-B1-9 on Model Lipid Bilayer.
Abinu, MHK, ISV, MRM
Lung surfactant is a mixture of protein and lipid that reduces surface tension at the air-water interface in the lungs and thus reduces the work needed to breathe. Two hydrophobic proteins, SP-B and SP-C, are thought to facilitate the re-spreading of fresh and recycled surfactant material...
The Kitaev model on the honeycomb lattice recently attracted considerable attention. However, in candidate materials, other interactions are present, and
among them the off-diagonal
ABSTRACT:
SNO+ is large multipurpose detector located at SNOLAB, Canada, Sudbury filled with liquid scintillator. The scintillator will eventually be loaded with a tellurium isotope, allowing to look for neutrino-less double beta decay which is extremely rare. This will determine if the neutrino is its own antiparticle. One of the main concerns for these rare event experiments is the...
The Hyper-Kamiokande (Hyper-K) experiment is the next generation of the Super-Kamiokande (Super-K) and T2K experiments investigating a breadth of physics topics including neutrino oscillation. The Hyper-K far-distance detector will contain ~40,000 20” photomultiplier tubes (PMTs), while the Intermediate-distance Water Cherenkov detector (IWCD) will contain ~500 multi-PMTs (each containing 19...
When a chemical bond breaks, all valence electrons in the bond will re-arrange and transfer as the nuclei are separating. The dynamical information of such electronic re-arrangement processes will be encoded in the kinetic energy of the ions if the breaking neutral molecule is ionized, allowing us to follow the entire electronic re-arrangement process by only observing the ions. Here, using...
The Canadian Light Source (CLS) is a 3rd generation synchrotron in Saskatoon that is used to produce extremely bright synchrotron light that can be used for research. The light at the CLS is produced by an electron storage ring which has an emmitance of 20 nm. A 4th generation synchrotron (CLS2) is planned which will reduce the emmitance to less than 1 nm and thus reduce the transverse beam...
Electron spins confined to quantum dots are a promising platform for scalable quantum computation. A necessary component of such a quantum processor is a microwave magnetic field (B
We prove that the state created via spontaneous parametric downconversion in a two-mode lossy cavity is a squeezed thermal state. We examine the case of generation in a side-coupled ring resonator.
In the context of quantum optics, two-mode squeezed states are routinely used as a source of continuous-variable (CV) entanglement for applications in the field of quantum information [1]. They...
SNO+ is a neutrino detector located 2 km underground at the deep clean lab facility - SNOLAB, in Vale’s Creighton Mine, in Sudbury ON. The primary goal of the SNO+ experiment is to search for an extremely rare, hypothesized phenomenon, neutrino-less double beta decay (0vbb) - the discovery of which will have a multitude of major implications in fundamental physics. Given the rarity of this...
From cytoskeleton to centriole, we investigate the photonic inner workings of the living cell. The cytoskeleton provides the structural organization of the cell, as the supporting architecture for all known forms of life. A major structural unit of this architecture is the cellular “microtubule,” a hollow tubular body composed of individual units of the protein “tubulin” organized in an array...
The simplest example of geometric frustration is found in the two-dimensional triangular lattice. While the ground state of the Heisenberg model in this lattice is known to be Néel ordered, some recent low-temperature experiments on various triangular lattice compounds have unambiguously demonstrated the presence of short-range ordering, continuous excitation spectra, and non-trivial spin...
We use dynamical self-consistent field-theory simulations of interacting, self-propelled rods to study the fascinating time-dependent, inhomogeneous structures observed during the growth of a colony of twitching Pseudomonas aeruginosa bacteria confined at the interface between a glass substrate and agar. These collective patterns in colony growth are relevant to early-stage biofilm...
Strong field physics, femtosecond (1 fs =
The superconducting order parameter of Sr
Molecular dynamics simulations are, in principle, numerically exact, but severely restricted with respect to the accessible time- and length-scale of the system studied. Stochastic simulations offer an alternative modeling method that overcomes these limitations. Unfortunately, the relation between the properties of the original system and the parameters used in stochastic modeling is not...
The possible existence the magnetic monopole is strongly motivated by theories and extensively tested in experiments. Searches at the LHC have been exclusively conducted with proton-proton collisions. However, the LHC not only collides protons but also heavy ions. Highly relativistic ultraperipheral collisions (UPC), where the ion-ion impact parameter exceeds the ion’s diameter, act as a...
We demonstrate a novel method to measure the temporal electric field evolution of ultrashort laser pulses. Our technique is based on the detection of transient currents in air plasma. These directional currents result from subcycle ionization of air with a short pump pulse and the steering of the released electrons with the pulse to be sampled. We assess the validity of our approach by...
The Kosterlitz-Thouless (KT) transition is a topological transition in a model where magnetic vortex and antivortex spin structures are created in an infinite, isotropic, 2D magnetic system. The transition occurs when bound vortex-antivortex pairs unbind due to thermal energy at the temperature
We show that the observed far-field behavior of sunlight on the earth’s surface, located in the near-field region, is due to the small angular width it subtends at the center of the sun. The sun is modelled as an incoherent spherical source. The cross spectral density at the surface of the source is described by a Dirac delta function. The asymptotic far zone behavior of the cross spectral...
The Higgs boson was observed at the Large Hadron Collider (LHC) at CERN in 2012. Its existence confirms the Higgs field which explains how some particles have mass while others do not. Since 2012, an important task has been to search for the neutral Higgs boson’s charged siblings. In the Standard Model (SM), the Higgs boson is a massive neutral particle observed at a mass near 125 GeV. The...
Bioanalytical sensors based on field-effect transistors (bioFETs) are emerging as promising tools to measure the kinetics of biopolymers such as proteins and DNA strands. This class of biosensors is based on an ultra-miniaturized electronic circuit whose conductance is very sensitive to the variations of the electrostatic potential in its environment caused by conformational changes in the...
Until recently, there has been a general belief that carrier doping destroys spontaneous polarization in ferroelectric materials. However, a small number of materials have been discovered in which ferroelectricity persists into the metallic state. Motivated by this, we study a theoretical model for a MOSFET-like system comprising an insulating polar cap layer and a metallic ferroelectric thin...
The detected spectrum in the Unruh effect is Planckian for massless fields. The reason is that the latter display a linear dispersion relation. It is also well known that for massive fields, the detected spectrum in the Unruh effect would lose its Planckian profile. Remarkably, the relativistic Doppler shift approach to the Unruh effect shows that, just like with massive fields, fields with...
With advances in nanofabrication, modelling the optical properties of nanoscale systems is critical.
The optical response of nanostructures can be simulated using the bulk permittivity of the constituent materials (1). The permittivity is generally assumed time-invariant and spatially dispersionless. While these approximations are enough for the simulations of most systems, in some cases...
Dynamical backaction resulting from radiation pressure forces in optomechanical systems has proven to be a versatile tool for manipulating mechanical vibrations. Notably, dynamical backaction has resulted in the cooling of a mechanical resonator to its ground-state, driving phonon lasing, and observing the optical-spring effect. In certain magnetic materials, mechanical vibrations can interact...
An orbital free related density functional theory based on the principles of polymer self-consistent field theory is used to calculate the electron densities, bond energy, bond length and fundamental vibrational frequency of homonuclear diatomic molecules. A simple exchange-correlation functional that neglects correlations is used, and the Pauli potential is based on Edwards–Flory-Huggins...
Astronomical and cosmological observations strongly suggest the existence of dark matter in the Universe. The favourite candidate is the WIMP (Weakly Interacting Massive Particles) and can be detected directly via elastic scattering on the target nuclei. Physicists are relying on more innovative and sensitive detectors in hope of capturing the nuclear recoil created by this mysterious...
A prototype medical device has been developed and built at Western University to image adolescents with hemophilic arthropathy. The device consists of a plastic cylindrical tub able to rotate freely about a base plate. A 10 MHz linear array ultrasound transducer by Canon Medical Systems is mounted to the inside of the tub pointed toward its center. The tub is filled with water to act as a...
Advanced materials, including: superconductors, light emitting materials and battery materials, play an ever increasing role in society today. Studying these materials is key to reducing overall energy consumption for everyday technology. Soft x-rays have the ideal energy for probing the electronic properties of typical elements in these materials; x-ray absorption spectroscopy (XAS) and x-ray...
The spin state of an electron has a 3-dimensional vector representation. In spin-orbit coupling (SOC), an electron’s external momentum becomes linked to its spin vector. This phenomenon appears in many different systems, including atomic and crystal band structure, (quantum) spin-Hall systems, and topological insulators. Previous experiments have used Raman coupling to generate and study...
By engineering an anti-parity-time (anti-PT) symmetric cavity magnonics system with precise eigenspace controllability, we observe two different singularities in the same system. One type of singularity, the exceptional point (EP), is produced by tuning the magnon damping. Between two EPs, the maximal coherent superposition of photon and magnon states is robustly sustained by the preserved...
The NEWS-G experiment uses a spherical proportional counter filled with gas in order to detect potential dark matter particles that can ionize the gas after a nuclear recoil. The detector works by attracting the free electrons towards the center of the sphere where there is a high voltage anode inducing a radial electric field. Near the anode, the accelerated electrons then cause a Townsend...
Autopsy studies indicate that the distribution of axons throughout the brain could differ in brains with and without schizophrenia. MRI has inferred axon diameters and distribution in the brain, typically for axons larger than 5 μm in diameter. The goal of this work is to modify these methods to adapt oscillating gradients (OG) to target small axons (1 to 2 μm range) which constitute the...
During earthquakes, the travelling speeds of seismic waves can change due to the heterogeneous nature of the earth’s crust. However, it remains an open question which factors most influence seismic wave speed changes. In this context, we use lab-scale experiments to study how heterogeneities such as cracks and ambient humidity affect the way that elastic waves interact in porous sandstone. We...
Gravitational Wave (GW) detection from continuous sources such as pulsars is an anticipated discovery. However, due to exceedingly weak signals, detection is challenging. In this presentation, we detail the derivation of a Fourier transform of a continuous wave signal amenable for detection of the GW signal from a pulsar. We also present an easy to implement algorithm for computing peak...
The classical Einstein-de Haas (EdH) effect [1] is a AC mechanical torque arising from a time rate of change of net magnetization, and represents the intrinsic relationship between magnetism and mechanical angular momentum. Nanofabrication of torque sensing devices is opening new avenues for exploration and applications of the EdH effect. The scale-up of resonance frequencies with continued...
The human brain is a magnificent system with highly complex functionalities such as learning, memory, emotion, and subjective experience. Over the past decades, it has been proposed that quantum physics could help answer unsolved questions in life science. Here we present a quantum model that could shed light on the mechanisms behind xenon-induced anesthesia and the lithium effects on...
Chiral enantiomers are notoriously difficult to differentiate as they have the same chemical and physical properties. Circularly polarized light has been shown to be able to distinguish between them, but the sensitivity is low, on the order of a few percent signal difference. However, in 2019 [1], an ultrafast multi-pulse scheme has been developed which can theoretically elicit responses of up...
Several parallels can be drawn between the perovskite iridate Sr
The NEWS-G experiment aims for the direct detection of low mass Weakly Interacting
Massive Particle (WIMP) dark matter using Spherical Proportional Counters (SPC). At the center of the SPC, a small sensor held at high voltage drives the drift of the primary ionization and provide the amplification needed to detect sub-keV nuclear recoils down to single electrons. The ACHINOS is a novel...
Studies of exchange coupling at interfaces in permalloy/cobalt oxide bilayer microdisks are made possible by measurements of a full AC magnetic torque vector [1]. Magnetic cross-product torque involves a linear combination of perpendicular moment and magnetic susceptibility, yielding the rotational magnetic anisotropy or stiffness of the spin texture in response to torque. Single-axis torque...
MATHUSLA (MAssive Timing Hodoscope for Ultra-Stable neutraL pArticles) is a long-lived particle (LLP) detector which would be constructed on the surface above CMS and is currently in its planning stages. This large-area detector would be composed of several layers of solid plastic scintillator, with wavelength-shifting fibers connected to silicon photomultipliers (SiPMs), allowing us to...
We investigate in the present work the doubly excited states (DES) in the Helium-like O6+ and F7+ ions. The interaction of these systems with X-ray laser pulses can cause the DES to appear in their energy spectra due to the strong correlation between the electrons. The formation of the DES can be followed by a decay by electron emission (autoionization) causing the parent ion to lose its...
The major ongoing upgrade of the ATLAS detector at the Large Hadron Collider at CERN consists in the replacement of parts of its muon spectrometer. The so-called New Small Wheels (NSWs) will be covered with two detector types that must trigger on and track outgoing particles - one type is small-strip thin gap chambers (sTGCs) assembled into modules of four layers. Canadian-built sTGC modules...
Majorana zero modes (MZM) have been a focal point of the condensed matter physics
community in recent times due in part to their potential applications in quantum computation.
Most notably, the exotic exchange statistics of MZMs form the basis of
topologically protected quantum gates. The physical exchange, or braiding, of MZMs is often modeled in networks of 1D topological superconducting...
The quantum dot cellular automaton (QCA) is a device that uses the interaction between confined electrons in aligned cells to transfer and process information. In QCA architecture, two antipodal arrangements of two electrons confined in square shaped cell are defined as digital “0” and “1”. QCA requires no electrical current for its operation therefore, extremely low power computing can be...
Since the magnetic skyrmion is a topologically protected particle-like domain in the ferromagnetic film, it can survive under thermal agitations and shows Brownian motion. The skyrmion system can be an ideal platform to design unconventional computers like stochastic/Brownian computers. Therefore, investigation of the Brownian motion of the magnetic skyrmion is now the subject of scientific...
From 2015 to 2018, the Large Hadron Collider (LHC) collided protons at an unprecedented center of mass energy of s=√13 TeV. The ATLAS detector recorded an integrated luminosity of 139fb
Motivated by magnetotransport experiments on magnetic topological insulators, a theoretical study of Dirac cone electrons coupled to magnetic moments has been done [1]. That work showed that the electronic response is determined by the magnetic configuration - the electronic spectrum is gapped in a region of the ferromagnetically ordered moments, but the gap vanishes at domain walls. This...
We consider the antiferromagnetic anisotropic Haldane model with large spins, in a region where a perturbative treatment is indicated. The Néel order is frustrated by periodic boundary conditions imposed on an odd-numbered chain, resulting in a highly degenerate groundspace spanned by solitons. We study the pertrubative groundstate entropy of entanglement for different scenarios, and compare...
High-finesse optical nanocavities coupled with nanomechanical torque sensors have enabled highly sensitive and broadband readout of magnetic torques, from timescales involving quasi-static hysteresis response to radio-frequency magnetic susceptibility [1-3]. The extension of torque magnetometry to higher mechanical frequencies will grant further access to spin dynamics, including mechanical...
P-type point contact (PPC) high-purity Germanium detectors have gained substantial interests in the search for neutrinoless double beta decay (0νββ) due to their background-rejection capabilities and excellent energy resolution. The drift time of charge carriers in the detector can be used in determining the position of an energy deposition and identifying sources of the background. One can...
Asymmetric charge transport at the interface of two materials with dissimilar electrical properties, such as metal/semiconductor and p-n junctions, is the fundamental feature behind modern diode and transistor technology. Spin pumping from a ferromagnet into an adjacent non-magnetic material is a powerful technique to generate pure-spin-currents, wherein spin transport is unaccompanied by net...
EMPHATIC (Experiment to Measure the Production of Hadrons At a Testbeam In Chicagoland) is a low-cost, table-top-sized, hadron-production experiment located at the Fermilab Test Beam Facility (FTBF) that will measure hadron scattering and production cross sections that are relevant for neutrino flux predictions. High statistics data will be collected using a minimum bias trigger, enabling...
Hybridization of disparate physical systems is a key area of research in harnessing quantum technologies. Exploiting hybridized states can mitigate perturbative effects of reading out quantum states or even enable new devices based on new material properties associated with hybrid quasiparticle excitations. In the area of magnetism a particularly prominent area of progress is the exploration...
The highest energy range of the solar neutrino spectrum is dominated by
DEAP-3600, hosted at SNOLAB, has been designed for the search of WIMPs, Weakly Interacting Massive Particles; its target of 3.3 t of liquid argon is the largest direct detection experiment. In addition to its sensitivity to WIMPs, DEAP-3600 is sensitive to super-massive dark matter candidates with masses up to the Planck scale. At dark matter-argon cross-sections above 10^{-24} cm^2 and dark...
DEAP-3600 is a liquid argon detector designed to directly detect dark matter by searching for nuclear recoil (NR) events caused by elastically scattered weakly interacting massive particles, a prime candidate for dark matter. Pulse-shape discrimination properties of the argon allow for significant separation between electromagnetic recoil (ER) events and NR events. The majority of the events...
Longstanding evidence from observational astronomy indicates that non-luminous "dark matter" constitutes the majority of all matter in the universe, yet this mysterious form of matter continues to elude experimental detection. The study presented in this talk is part of an ongoing programme to search for dark matter production in high-energy proton-proton collisions at the Large Hadron...
The last supernova near our galaxy was in 1987. HALO-1kT will be a low background galactic Supernova detector that uses 1kT of lead as the target for supernova neutrinos and helium-3 neutron counters to detect neutrons produced from the neutrino-lead interactions. The neutrons are then effectively captured by He-3 and converted to electrical signals by the proportional counters.
As with...
Telescope Array experiment has recorded several short time bursts of air shower like events. These bursts are very distinct from conventional single showers, and are found to be strongly correlated with lightnings. We proposed these bursts represent the direct manifestation of the dark matter annihilation events within the so-called axion quark nugget model. We discuss how to test this...
Since the discovery of the Higgs boson at the LHC in 2012, no sign of new physics beyond the Standard Model has been found. The SUSY and exotic particles searches have not uncovered signs of new physics, as the model-dependent searches. In recent years, multiple unsupervised machine learning methods have been proposed to search for new physics at the LHC. This poster will explore the use of a...
The Cryogenic Underground TEst Facility (CUTE) is fully operational underground at SNOLAB. The facility can host up to six of the next generation SuperCDMS cryogenic detectors, and allows for the opportunity to search for low-mass dark matter while testing the new detectors. The SNOLAB cleanroom laboratory provides a low-background and low-cosmogenic-activation environment for CUTE operations....
The 20th century has been dominated by the realization that symmetry and symmetry breaking influence the forces that govern our universe and are keys to much of the novel phenomena observed in materials today. Recently it has been realized that, even if the global symmetry of a system is retained, a local symmetry breaking can still drive a variety of novel fascinating behaviors. In this...
How did the first genetic code and the first forms of cellular appear in the early life, about 3.5 billion years ago, of terrestrial and Earth‐like exoplanets? This question has become especially timely with the discovery of an ever‐increasing number of rocky exoplanets where liquid water is present and the successful landing of Perseverance, the latest of NASA’s Mars rovers to search for...
We numerically analyze the spectrum of the Laplacian on the moduli space of a genus zero Riemann surface with four punctures via a perturbative expansion of the path integral of Liouville theory. Our results furnish evidence that the eigenvalues obey the statistics of a random matrix in the Gaussian Orthogonal Ensemble. We comment on possible implications for the quantum geometry of Riemann...
Nuclear transitions provide a means to probe light, weakly-coupled new physics and portals into the dark sector. Particularly promising are those transitions that can be accessed through excited nuclear states that are resonantly produced, providing a high-statistics laboratory to search for MeV-scale new physics. In this talk the so-called X-17 anomaly will be discussed, which is a 7σ...
Atmospheric pressure discharges in a dielectric barrier configuration, resulting in non‐local thermodynamic equilibrium (nLTE) plasmas, are used in photovoltaics, photocatalysis, solar cells, water treatments and depollution, as well as for modifying the surface of wood. They can also be used to generate nanoparticles (NPs) and nanocomposites. They can be also integrated for novel approaches...
By exploiting effects such as quantum superpositions and entanglement, quantum computers could solve problems that are intractable on standard, classical, computers. While building a full-scale quantum computer capable of rivalling with today’s supercomputers remains a challenge, the last few years have seen tremendous improvements in our ability to build small superconducting quantum...
The GlueX Experiment at Jefferson Lab has been collecting high-energy photoproduction data since 2016 as part of its search for hybrid mesons, mesons in which the
gluonic field has been excited. An over views of the GlueX experiment and its physics program, including first results and the ongoing searches for hybrids will be presented.
These results include studies of photoproduction...
Skyrmions are a topologically non-trivial state that has been observed in a number of different magnetic materials, such as the chiral cubic magnets Cu2OSeO3, FeGe, and MnSi. In these non-centrosymmetric systems, competition between the symmetric exchange interaction and Dzyaloshinskii-Moriya interaction results in the formation of non-trivial incommensurate spin textures, such as skyrmions....
Studies in paleontology have been fast developing with the recent employment of new technologies. Among these new tools, the use of dedicated synchrotron radiation facilities to probe specimens long extinct have added a new layer of contribution to the knowledge of how those animals lived, died and, in some cases, evolved into the diversity of life that we witness nowadays.
In this talk,...
One of the problems educators often confront is the lack of preparedness and engagement of physics students as they enter university. Two potential causes are 1) some students think physics is about tedious descriptions of balls rolling down ramps, 2) students may have no motivation for learning algebra. Special relativity (SR) is no weirder for high school students than for university...
We present the first laser cooling of antimatter, and results of precision spectroscopy performed with laser-cooled antihydrogen atoms. The ALPHA collaboration at CERN is engaged in precision testing fundamental symmetries between matter and antimatter using antihydrogen. Recently, we have made advances in the production, collection, storage, and laser addressing of antihydrogen. These efforts...
We propose to use 4-level systems with an additional symmetry to encode pairs of coupled qubits. The chosen symmetry allows clusters to perform universal quantum computation on their encoded qubits, and gives full control over their energy spectrum. Each level can be dynamically decoupled from its immediate environment, modelled by its tunneling-coupling to a semi-infinite lead, turning the...
We elucidate the vector space (twisted relative cohomology) that is Poincar\'e dual to the vector space of Feynman integrals (twisted cohomology) in general dimension. These spaces are paired via an inner product called the intersection number -- an invariant which can be computed algebraically. In this language, reduction of an integrand modulo integration-by-part identities is simply its...
To utilize the advantages of different quantum platforms, we need an interface (transducer) to transfer quantum information from one to another. Unfortunately, realistic transducers are imperfect due to, e.g. weak interaction strength or unwanted coupling. In this talk, I will present a surprising strategy to remedy the transduction imperfections: by applying a bad transducer twice [1]. I...
In response to the needs for ventilators for critically ill Covid-19 patients a collaboration of international particle physicists, engineers, software specialists, industry and medical specialists came together to create rapidly a simple, low-cost, open-source ventilator tailored specifically for such patients. The project was initiated by Professor Cristian Galbiati, spokesperson of the...
Applying a novel computational technique to the structure of Candida Antarctica Lipase B, which is an efficient catalyst with a wide range of applications, this study investigates the potential for its industrial applications owing to its activity under extreme conditions. We examined themolecular effects of distinct solvents on the stability of CalB at high temperatures, aiming to con-tribute...
We are exploring solid state precipitation methods to grow high-quality Ge-Sn nanoparticles with controlled compositions and band gaps. There have been decades of research to produce semiconductor nanoparticles using wet chemistry synthetic techniques, however many of these approaches are not compatible with current CMOS device manufacturing. Si-Ge-Sn alloys offer great new material...
We describe the offset logarithm function and illustrate its applications to physics. The offset log can be considered an extension of the logarithm function, and it can also be considered as a generalization of the Lambert W function.
The offset log function shows up in a variety of physical and biological models, such as the mean field model (Weiss model) of ferromagnetism, and models...
Information engines are the modern realization of the Maxwell demon, a thought experiment that revealed that information is also a thermodynamic quantity. We build and study a simple information-to-work engine, which consists of a heavy bead, in a water bath, trapped by optical tweezers. The bead undergoes Brownian motion due to the thermal fluctuations in the bath. The position of the bead is...
We combined information from Fluorescence Correlation Spectroscopy (FCS), Nuclear Magnetic Resonance (NMR), Small-Angle X-ray Scattering (SAXS) and Single-Molecule Förster Energy Transfer (smFRET) to calculate conformational ensembles for the neuronal transcription factor initiation protein 4E-BP2. This is a 120-residue intrinsically disordered protein which toggles between an active,...
Numerous advances have been made in the field of Si photonics, attractive in terms of cost, power consumption and performance in comparison to conventional technologies. Photodetectors which converts light to electrical signals are vital parts of Si photonics system. Advances in materials science have led to photodetectors that operate in the short infrared wavelength range (1.3 - 2.5µm). This...
Over the last decade, The ALPHA experiment at CERN produced a series of ground-breaking results, having demonstrated the first ever trapping and laser cooling of antihydrogen atoms, and precisely measured many of their physical properties, including the 1s-2s transition and hyperfine splitting. A new ALPHA-g apparatus is being built to precisely measure the gravitational mass of antihydrogen....
Approximation of the ground state wave function and energy of a quantum system is often achieved using perturbation theory or the variational method. The former approach suffers from the requirement that the Hamiltonian perturbation be small enough for the series to converge while the variational method is only as good as the choice of functions used in the expansion, providing only an...
We investigate in the present work the doubly excited states (DES) in the Helium-like O6+ and F7+ ions. The interaction of these systems with X-ray laser pulses can cause the DES to appear in their energy spectra due to the strong correlation between the electrons. The formation of the DES can be followed by a decay by electron emission (autoionization) causing the parent ion to lose its...
The Feynman quantum-classical isomorphism between classical statistical mechanics in 3+1 dimensions and quantum statistical mechanics in 3 dimensions is used to relate classical polymer self-consistent field theory to quantum density functional theory. This allows the theorems of density functional theory, which connect single particle density descriptions of quantum systems to wave function...
Like many, a combination of curiosity, self-preservation, and dissatisfaction with what the news was calling "analyses", drove us to begin our own analyses of publicly available COVID-19 data. I will present some of the simple approaches we came up with, and our more interesting observations regarding the effectiveness of restrictions and the variations over time in the mortality rate per...
Antimicrobial drug resistance is a growing health threat that is predicted to kill 10 million people per year globally by 2050 unless preventative measures are put in place. The first step in implementing these measures is to gain a better understanding of the fundamental processes involved in antimicrobial drug resistance through quantitative approaches from fields such as biophysics,...
Phytoglycogen occurs naturally in the form of compact, 42 nm diameter glucose-based nanoparticles in the kernels of sweet corn. 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 nanoparticles can be altered through chemical...
THESIS: The ontology of spacetime should not be modelled as a single universally-shared 4D spacetime manifold.
THE CONSENSUS SPACETIME ONTOLOGY: The accepted ontology of classical spacetime is of a 4D differentiable manifold of events. Although different observers may assign different coordinate labels to events, it is conventionally asserted that the underlying reality is that of a...
The simulation of quantum systems is inherently difficult due to the exponentially scaling of the state that must be simulated for a general system. One clear way to get around this problem is to utilize the properties of the quantum physics it’s self, ergo simulate quantum physics on quantum physics. An exciting frontier in quantum information science is the realization and control of complex...
Separating and analyzing DNA, RNA or proteins is often done through gel electrophoresis. This simple technique is conducted millions of times in labs every day world-wide. Analysis of the gels is typically done visually on a photo by comparing measured intensities with a well-defined reference ladder. Using digital photography and image analysis, we have developed a technique to quantitatively...
Observables in the hard exclusive leptoproduction of real photons can be cleanly expressed in terms of the compton amplitudes involving generalized parton distributions (GPDs). This process can be factorized into the product of a short-distance partonic subprocess with a long-distance, off forward hadronic matrix element. They involve nonlocal quark and gluon operators and are naturally...
The problem of stretching flexible polymers was covered in a seminal paper by John F. Marko and Eric D. Sigga in 1995, where they used the wormlike chain model to calculate the force required to stretch long segments of DNA. Their approach used a ground state dominance method to solve the modified diffusion equation, applicable to long (flexible) chains only. Here, using the same Green’s...
Trapped-ion quantum states are well-known to be good candidates for qubits in quantum computing. I will study the application of an adiabatic method known as STIRAP to achieve qubit switching. Stimulated Raman Adiabatic Passage (STIRAP) is a method of quantum control that utilizes a specific atomic structure known as a 3-Level Lambda System (3LLS). The system consists of two ground states that...
In the past 20 years, large-scale datasets of cell phone traces have emerged as a key proxy to study human movement patterns, and how those patterns change in response to exogenous events such as natural disasters or terrorist attacks. These data have proven especially useful to understand the effects of public policy in the current COVID-19 pandemic, where "lockdowns" and other mobility-based...
The novel method we developed for understanding energy exchanges between argon (Ar) carrier gas and precursor molecules in a large-area (216 cm
The primary goal of the GlueX program is to explore the spectrum of light-quark mesons for excitations with explicit gluonic degrees of freedom, as predicted by Quantum Chromodynamics. These particles are termed hybrid mesons and some are predicted to possess exotic JPC quantum numbers. Lattice QCD predicts patterns of hybrid states with masses in the 2-GeV/c^2 range, which can be accessed in...
When nanopores are used to capture and translocate DNA molecules through a wall or membrane, the resulting capture rate is essentially independent of their molecular size, making the process incapable of changing relative concentrations in a mixture. Using Langevin Dynamics simulations, we show that it is possible to use pulsed fields to ratchet captured semiflexible molecules so that only...
It was recently demonstrated that the layered van der Waals bonded material MnBi
Belle II is a B-Factory experiment designed to produce precision measurements of CP violation in the weak sector as well as search for Beyond the Standard Model particle physics. The
The nonclassicality of simple spin systems as measured by Wigner negativity is studied on a spherical phase space. Several SU(2)-covariant states with common qubit representations are addressed: spin coherent, spin cat (GHZ/N00N), and Dicke (W). We derive an upper bound on the Wigner negativity of spin cat states that rapidly approaches the true value as spin increases beyond
The Antihydrogen Laser Physics Apparatus (ALPHA), at the European Centre for Nuclear Research (CERN) antiproton decelerator facility, uses low energy antiprotons in a bound state with a positron to produce and trap antihydrogen [1]. Given the long history of atomic physics experiments with hydrogen, spectroscopy experiments with antihydrogen offer some of the most precise tests of quantum...
We seek to design experimentally feasible broadband multiplexed optical quantum memory with near-term applications to telecom bands. Specifically, we devise dispersion compensation for an impedance-matched narrow-band quantum memory by exploiting Raman processes over two three-level atomic subensembles, one for memory and the other for dispersion compensation. Our proposed...
Morphogens (often acting as transcription activators or repressors) govern pattern formation and cell differentiation during early embryogenesis. Abnormal distributions of morphogens can result in developmental defects or even death. Oftentimes, thresholds of concentrations of morphogens behave like an ON/OFF switch for the activation or repression of downstream genes. Thus accurate...
We model a number of both closed-packed and non-closed-packed crystals inside a cholesteric liquid crystal (LC) with different pitch values and nematic LC through the Landau–de Gennes free-energy method[1]. We investigated the anisotropic interactions between particles with heterogeneous boundary conditions inside both nematic and cholesteric liquid crystals[2]. The results show that it is...
High School physics programs across the country all include outcomes related to subatomic particles and their interactions with matter and fields. Despite this, many high school teachers have received little training in particle physics and are often unaware of the contributions Canadian Physicists are making in this area. To help bridge the gap between university research and high school...
I will present terahertz time-domain spectroscopy measurements of the dynamical conductivity of MnSi, and compare them to Fermi liquid theory at low temperatures and low frequencies. I will also describe a new methodology for terahertz time-domain data analysis, developed to perform this comparison, which has higher sensitivity to fit quality than earlier methods. Within the extended Drude...
The Kaon LT experiment (E12-09-011) at Jefferson Lab, USA was designed to study the LT separated cross-section of the reaction
The analysis of human nail clippings to determine the concentration of certain elements of interest is now fairly common. Results can be used to assess exposure to various elements and their absorption into the body. When nail clippings are used as a biomarker in this way, they are typically analyzed by a method such as inductively coupled plasma-mass spectrometry (ICP-MS) or instrumental...
The Migdal ?effect in a dark-matter-nucleus scattering extends the direct search experiments to the sub-GeV mass region through electron ionization with sub-keV detection thresholds. In this talk, I'll present a rigorous and model-independent "Migdal-photoabsorption" relation that links the sub-keV Migdal process to photoabsorption. This relation is free of theoretical uncertainties as it only...
Data collected at the LHC are analyzed by the ATLAS collaboration for evidence of dark matter. In this talk, a fast simulation of the ATLAS detector response using the Delphes software is assessed for dark matter models with a leptonically decaying
Chemical synthesis of fuels using sustainable energies is one of the main challenges for the development of a circular economy. In recent years, because of their flexibility and capability of not using any rare earth materials or noble metals, atmospheric pressure plasmas have been the focus of intense research activities for the reduction of stable molecules such as CO2 and N2. In this...
Magnetic polaritons have been known and observed for decades in ferromagnetic resonance spectroscopy experiments. A revival of interest and reinterpretation of these classical experiments, over the last decade, have focussed on the strong interaction between microwave photons and the collective spin excitations of ferromagnetic specimens in resonant cavities. Some of these studies have brought...
One striking property of the Landau level spectrum of a Weyl semimetal (WSM) is the existence of a chiral Landau level in which the electrons propagate unidirectionnaly along the magnetic field. This linearly dispersive level profoundly influences the optical properties of the WSM especially if it originates from a tilted Weyl cone. In this talk, we compare the behavior of the magneto-optical...
Recent developments of the relativistic nuclear field theory (NFT) on the fermionic correlation functions will be presented. The general non-perturbative equation of motion framework is formulated in terms of a closed system of non-linear equations for one-body and two-body propagators. The present formulation provides a direct link to ab-initio theories and extends the explicit treatment of...
Photons, the quanta of light, possess several different degrees of freedom, e.g., frequency, polarisation, spatial and temporal modes, which can be used as platforms for quantum information applications. Polarisation, corresponding to the vectorial nature of light, is bi-dimensional and can represent ‘0’ and ‘1’ in the digital world. Unlike, polarisation, transverse and temporal modes would...
Ultracold neutrons are neutrons that exhibit the peculiar behavior of being able to be stored in material bottles for periods ranging up to their beta-decay lifetime (~15 min). They present an attractive avenue for performing fundamental neutron experiments such as: searching for a non-zero neutron electric dipole moment (nEDM), precise measurement of the neutron lifetime, and precision...
Alzheimer’s disease is a neurodegenerative condition marked by the formation and aggregation of amyloid-𝜷 (A𝜷) peptides. It is the most common cause of dementia worldwide, with numbers expected to double each year, reaching 81 million by 2040. There exists, to this day, no cure or effective prevention for the disease; however, there is evidence that a nutritious diet and certain food compounds...
In order to give our students the opportunity to learn collaboratively in our introductory physics labs, we developed a series of hour-long collaborative activities that students engaged with via Zoom using the IOLab lesson player. We envisioned and developed the activities to revolve around four student roles (experimentalist, theorist, archivist, and manager) to help students share their...
A 3D topological insulator (TI) hosts an odd number of Dirac cones as its 2D surface states spectrum. The states are exponentially localized to the surface and their (pseudo)spin is locked to the surface momentum direction due to spin-orbit interaction. If the TI is also magnetic there are fixed magnetic moments on the surface, co-existing with the itinerant Dirac electrons. The magnetic...
Here I discuss the possibilities to use nanomechanical resonators to converter information between microwave and optical domains. Additionally, I demonstrate an on-chip magnetic-free circulator based on reservoir-engineered electromechanical interactions. Directional circulation is achieved with controlled phase-sensitive interference of six distinct electromechanical signal conversion paths....
More than 30 million individuals worldwide are living with Alzheimer’s Disease. To further the current understanding on this neurodegenerative disease, we developed a technique to create amyloid peptide clusters in synthetic, brain-like membranes, which mimic the senile plaques found in the brains of Alzheimer's patients. I compared the molecular functioning of homotaurine, a peptic...
How diffusivity (e.g., of proteins in the plane of biomembranes) is impacted by obstruction has been explored using Lattice Monte Carlo methods for random and periodic obstacle configurations. However real systems are neither periodic nor totally random. We present a study of transient and steady-state molecular diffusion in two-dimensional ”Fuzzy” systems of immobile obstacles, \textit{i.e.,}...
We identify potentially the world's most sensitive location to search for millicharged particles in the 10 MeV to 100 GeV mass range: the forward region at the LHC. We propose constructing a scintillator-based experiment, FORward MicrOcharge SeArch (FORMOSA) in this location, and estimate the corresponding sensitivity projection. FORMOSA, placed
In an earlier study on the Wiedemann–Franz Law and the thermoelectric figure of merit (FoM), we studied the electronic effects in detail. We briefly investigated the role of the lattice thermal conductivity in enhancing the FoM and derived the characteristic equations in the form of an offset-logarithmic function (a special case of the generalized Lambert W function) [1]. This work follows up...
Despite incredible experimental progress in quantum optomechanics, the intrinsically weak coupling between light and motion remains a bottleneck for accessing the full potential of these systems. While a strong pump field can parametrically enhance the optomechanical coupling, it also acts to obscure the fundamental nonlinearity of the interaction and hinders integration with single photon...
Recently, there has been considerable interest to study the nonlinear properties of ensembles of
metallic nanoparticles and quantum dots [1,2]. Nonlinear optical properties can be used for
processing the information content of data images, on which the research can potentially induce a
revolution in electronic as well as photonic nanotechnology and nanomedicine. We have studied
the energy...
Optical quantum memory that has the ability to store and on-demand, recall the quantum states of light with high efficiency and fidelity which has several applications in linear-optical quantum computation, single-photon detection, quantum metrology, tests of the foundations of quantum physics is one of the essential elements in distribution of quantum entanglement for long distance quantum...
Cell membranes are complex dynamic structures, and their composition and structure are major determinants of pathology. It is now commonly accepted that the membranes’ physical properties, such as fluidity and thickness, are determining factors for permeability, partitioning of drug molecules, and protein aggregation. Membrane-interacting molecules can in some instances be expected to have a...
The pandemic timeline has turn out to be much longer than initially expected, and the need for a remote teaching still remains. The immediate switch to the remote teaching that happened due to COVID-19 in March 2020, not surprisingly, had the greatest detrimental effect on laboratory components of physics courses. Smaller courses during summer time allowed us to test different approaches and...
Thin film deposition on substrates inclined with respect to the flux of evaporated materials can be used to produce anisotropic porous nanostructures displaying effective anisotropic optical properties at the wavelength scale. When the orientation of the substrate is changed during the deposition process, sculptured thin films are grown, whose optical properties can be continuously controlled...
Blood banks all around the world store blood for several weeks ensuring the availability of blood for transfusion medicine. Although the storage conditions have been optimized for decades it has become evident that red blood cells (RBC) undergo numerous changes when being stored.
We investigated the effect of storage on the nanoscopic bending rigidity of RBC membranes with a combination of...
The existence of dark matter is widely accepted, with a well motivated theoretical candidate being a class of particles known as WIMPs (weakly interacting massive particles), which appear in the spectra of many extensions to the standard model.
We explore a particular WIMP-like model in which fermionic dark matter weakly couples to the muon/tau sectors of the standard model through a new...
Trapped ions for quantum information processing has been an area of intense study in the past twenty years due to the extraordinarily high-fidelity operations that have been achieved experimentally, and the recent microfabricated traps that offer a potential path to scaling the technology. Specifically, the Barium-133 trapped ion has been shown to have some of the highest fidelity operations...
The TUCAN collaboration aims to provide an ultra-precise measurement of the neutron electric dipole moment, resulting in a planned sensitivity of 10-27 e*cm. EDM experiments of this kind require measuring changes in the precession frequency of ultracold neutrons as they are subjected to parallel and anti-parallel electric and magnetic fields. In order to reach the planned sensitivity, precise...
Currently, the focus of plasma discharges in liquid is mainly to produce nanoparticles, to remove pollutant from water or to transform liquid fuels. In this paper, we aim to put forward a statistical study of the influence of various discharge parameters (e.g. applied voltage, pulse width, nature of liquid and electrode geometry) on the discharge characteristics, such as the discharge...
Due to their highly tunable physical properties and their biocompatibility, hydrogels-based drug delivery systems have sparked huge interests over the past twenty years. One of the reasons of this interest lies to the ability to encapsulate drug particles inside the porous hydrogel structure. In addition, by adjusting the density of cross-links in the gel matrix, it is possible to modify the...
We present the first ab-initio calculations of the structure factors for elastic spin-dependent WIMP scattering off
A programmable quantum simulator can simulate models of quantum many-body systems that may otherwise be impossible to be modeled with conventional computers. Simulation of such many-body quantum systems may further advance our understanding of exotic quantum materials, fundamental forces of nature, molecules for drug discovery, etc. Laser-cooled and trapped atomic ions serve as an ideal...
We use Langevin dynamics (LD) simulations to investigate single file diffusion (SFD) in a dilute solution of flexible linear polymers inside a narrow tube. The transition from single-file diffusion, where the mean-square displacement scales like
The kinematics of WIMP dark matter-nuclear scattering is drastically altered in the presence of inelastic dark matter, where the dominant dark matter component is up-scattered to a heavier state with certain mass splitting. With hundreds of keV mass splitting inelastic dark matter will evade the search in most direct detection experiments, where the momentum transfer is limited either by the...
Magnetic structures are known to possess magnetic excitations confined to their surfaces and interfaces, but these spatially localized modes are often not resolved in spectroscopy experiments. We developed a theory to calculate the confined magnon spectra and its associated spin scattering function, which is the physical observable in spectroscopy based on neutron and electron scattering, and...
I will share my experiences and lessons learned implementing the Investigative Science Learning Environment (ISLE) approach in a large online introductory class of hundreds of students. The ISLE approach is based on two intentionalities (Brookes, Etkina, & Planinsic 2020): (1) We want students to learn physics by thinking like physicists; by engaging in knowledge-generating activities that...
Bound-state beta-decay (
We apply the no-core shell model with continuum technique to investigate nuclear reactions involving p+7Li and n+7Be with 8Be as the composite system. This method enables accurate description of both bound states and the continuum using chiral nucleon-nucleon and three-nucleon forces as input. We report phase-shifts, astrophysical S-factors and cross-sections for a suite of scattering and...
In this talk, I will argue that treating the marginalization of certain groups in science as a workforce problem ignores the deeper issue: that wondering about the universe is a fundamental right. I will discuss what it means to create the conditions in which we all have a chance to know and love the night sky and all of the particles that populate it.
Nanocomposite (NC) thin-films are widely studied due to the multifunctional properties they can develop (optical, electrical, mechanical). A lot of methods are under development with a real attraction for processes at atmospheric pressure, such as dielectric barrier discharge (DBD).
Recently, a new process of nanoparticles injection in plasmas has been developed [1]. This method consists in...
Super-Kamiokande (Super-K) is a neutrino detector located in Japan used to study neutrinos from different sources (atmospheric, solar, supernovae and accelerator). Its research program includes search for proton decay and measurement of neutrino oscillations among others. It contains ~11,000 20 inches photomultiplier tubes (PMTs) surrounding a massive tank filled with 50 ktonne of ultra-pure...
I summarize recent work pointing towards the existence of a universal holographic light-front wavefunction for light mesons and nucleons. This holographic wavefunction, which describes simultaneously a bound state in light-front QCD and the propagation of string modes in a dilaton-modified 5-dimensional anti de Sitter spacetime, is a specific realization of the gauge-gravity duality. The...
1944 saw the height of the United States Manhattan Project efforts which was distributed between Los Alamos New Mexico, Oak Ridge Tennessee, and Hanford Washington. Since the Manhattan Project was spurred by the fear that Germany was building her own nuclear weapons, Allied anxiety continuously pondered the Nazi atomic progress. As Germany began to fall to the Allies, Gen. Groves commissioned...
Label-free vibrational spectroscopic imaging based on inelastic (Raman) light scattering represents a rapidly emerging platform for biology and medicine. My research program in Medical Physics and Biomedical Engineering develops novel instrumentation and analysis methods based on Raman spectroscopy and Coherent Raman Scattering (SRS) imaging combined with other nonlinear optical imaging...
This talk will describe three new experiments recently developed for the advanced physics lab at the University of Toronto. Students work alone and have 18 class hours to complete a lab. [1] When a low viscosity fluid (in this case air) is pumped into a narrow gap between two plates filled with a more viscous fluid (here mineral oil), the resulting expanding bubble is unstable to the formation...
Sterile neutrinos with masses around a few keV have been postulated to be viable dark matter candidates. This is, however, mostly in tension with various astrophysical observations, the most stringent being the X-ray bounds. In this talk, I would like to present a testable sterile neutrino dark matter production mechanism in the early universe. The idea is to introduce secret self-interactions...
Conductive and transparent metallic nanowire networks are regarded as promising alternatives to Indium-Tin-Oxides (ITOs) in emerging flexible next-generation technologies due to its prominent optoelectronic properties and low-cost fabrication. The performance of such systems closely relies on many geometrical, physical, and intrinsic properties of the nanowire materials as well as the...
We explore regions of parameter space that give rise to suppressed direct detection cross sections in a simple model of scalar dark matter with a scalar portal that mixes with the standard model Higgs. We found that even this simple model allows considerable room in the parameter space that has not been excluded by direct detection limits.
While a number of effects leading to this result have...
The behaviour of confined polymeric systems has been the topic of much recent research. The information from these studies may help guide the development and optimization of nanofluidic devices and understand the segregation of DNA chromosomes in prokaryotic cells. Some recent experiments examined two DNA molecules confined to a box-like cavity with strong confinement in one dimension. The...
Multiquark states have been of great interest among hadronic physicists, and despite the big breakthrough that came in 2003 with the discovery of the charmonium-like tetraquark candidate X(3872), their internal quark structure (e.g., molecular versus diquark clusters) are not well-understood yet. QCD sum-rule mass estimates for multiquark states can provide insights on possible internal quark...
Lattice gauge theory is an indispensible tool for non-Abelian fields, such as those in quantum chromodynamics where lattice results have been of central importance for several decades. Recent studies suggest that quantum computers could extend the reach of lattice gauge theory in dramatic
ways, but the usefulness of quantum annealing hardware for lattice gauge theory has not yet been...
The ATLAS detector at the Large Hadron Collider (LHC) at CERN is in the process of upgrading its silicon charged-particle tracker as part of the Inner Tracker (ITk) upgrade, in parallel with the LHC’s own High-Luminosity upgrade (HL-LHC). With ten times the radiation dose expected at the HL-LHC as compared to LHC, the silicon technology used in the ITk must demonstrate an excellent radiation...
Recent experimental studies in the hole-doped iron pnictide BaFe
Scientists of all backgrounds and genders,have made important contributions in science, technology, engineering and mathematics (STEM), but the participation of women remains low in many areas of STEM, including physics. What can we do to build an inclusive STEM community? I'll discuss recent studies and data that shed light on where we stand today and what we can do to improve.
High-luminosity fixed target experiments provide impressive sensitivity to new light weakly coupled degrees of freedom. In this talk, I will discuss the minimal case of a scalar singlet
Two-pulse COSY (correlation spectroscopy) EPR (Electron Paramagnetic resonance) sequence, utilized for distance measurements in biological systems using nitroxide biradicals, is investigated both analytically and numerically. The analytical expressions derived here for any orientations of the two nitroxide dipoles with respect to the dipolar axis, oriented at an angle \theta with respect to...
Inductively-coupled RF thermal plasma have been known and used in the last three decades for the spheroidization of powders, for the synthesis of single cation ceramics or metallic nanoparticles as well as for the deposition of coatings. This electrodeless plasma produces pure materials at a high throughput. Over the years, the chemical precursors used have evolved from single gas or solid...
Physics is widely recognised as a subject which often does not recognise the diversity of the societies in which it is practised. There are differences between countries, but there are many parts of the world where female participation at all levels in Physics is 20% or below. In the UK specifically, there is also low participation by some groups either ethnic groups or lower socioeconomic...
A test-bench is created that injects digital pulses that emulate ATLAS Liquid Argon (LAr) Front End Board electronic signal pulses in order to test prototypes. The prototypes are for new electronics for an upgrade to the CERN Large Hadron Collider that increases the rate of proton-proton collisions by an order of magnitude. This High-Luminosity Large Hadron Collider requires a completely new...
The prototypical superfluid, Helium-4 (
In 2014 the Executive Officer of the American Physical Society (APS), Kate Kirby, created an Ad-Hoc Committee on LGBT Issues (C-LGBT) charged with reporting on the obstacles to inclusion of LGBT physicists, a term which for the purpose of this report refers to persons who self-identify as lesbian, gay, bisexual, transgender, queer, questioning, intersex, or asexual, as well as other sexual and...
Ab initio approaches such as the no-core shell model with continuum (NCSMC) describe nuclei as systems of nucleons experiencing inter-nucleonic forces derived from the underlying Quantum Chromo-Dynamical (QCD) structure. This, along with the NCSMC's unified description of nuclear structure and reaction theory, provide a rigorous framework that can be applied to tests of fundamental...
Topological insulators are an interesting class of materials which host distinct zero/low-energy states at their boundaries. These symmetry-protected states can, for example, arise as Majorana zero-modes in various superconducting systems and have potential applications in quantum error correction. However, experimental study and verification of such zero-modes remains a challenge. Considering...
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-resolution Echelle spectrometer, high signal-to-noise optical emission spectra can be...
We experimentally demonstrate dissipative in a double pendulum system. Unlike the well-known spring coupled pendulum experiment, our experiment replaces the spring with the dissipative coupling device. Two pendulums are coupled by a device that employs Lenz's effect to dissipate energy through electromagnetic friction. To observe the influence of the dissipative coupling, we tune the natural...
Synchronization describes an interesting dynamical process of coupled oscillators.
Particularly, it refers to oscillators oscillating at the same frequency despite their
natural frequency difference. Besides, for a coupled two-oscillator system, its
hybridized eigenmodes can be mapped onto the Bloch Sphere.
We experimentally studied the relationship between synchronization...
The Light-only Liquid Xenon (LoLX) project aims to study the properties of light emission and transport in liquid xenon (LXe) using silicon photomultipliers (SiPMs). By investigating scintillation and Chernekov emission in LXe, LoLX will develop Cherenkov-scintillation separation with SiPMs as a background discrimination technique for low-background LXe experiments, e.g. searches for...
The rapid neutron capture process (
At energies over 100 TeV, the universe becomes opaque to photons limiting the range of high energy gamma ray observations to roughly within the Milky Way. Neutrinos on the other hand do not suffer from this drawback which makes them ideal messengers for studying extremely energetic astrophysical phenomena across the cosmos. Recent observations using neutrino telescopes have thoroughly cemented...
Since trapping the first cold antihydrogen atoms over 10 years ago, the ALPHA collaboration has established itself at the leading edge of antimatter science. Through a series of experiments located at the Antiproton Decelerator at CERN, the group has carried out a number of novel precision measurements, primarily on the spectral transitions of antihydrogen. ALPHA-g is the latest addition to...
Searching for low mass WIMPS has many challenges, the largest one being the discrimination between electron recoils and nuclear recoils within a given detector, the latter being a potential dark mater signal while the former is not. Many detectors cannot make this distinction and thus can only look so far in the low mass dark matter regime, but a new dark matter detector called the...
Over the last few decades, the study of nuclei and neutron-rich matter from first principles has entered a new era. This has partly been driven by the development of novel interactions between two or three nucleons. In an attempt to produce a systematic expansion, several groups have produced Effective Field Theory (EFT) interactions, whether of finite range (chiral EFT) or zero range...
Over the past 25 years, optical coherence tomography (OCT) technology has been used for clinical diagnostics of potentially blinding ocular (retinal and corneal) diseases because it offers a non-invasive approach, fast image acquisition rates and multi-functionality. However, clinical OCT systems lack the necessary resolution and imaging speed for in-vivo imaging of the cellular and...
This is a report on a project to interview the student body of the Concordia University Physics Department concerning teacher-students interaction. The goal of this research is to establish an easily implemented guideline of teaching methods for a professor to use in the classroom. Students were asked to complete a questionnaire that included a request to describe the teaching style of their...
Most physicists know that Rutherford proposed the presence of an atomic nucleus in 1911 when he was in Manchester based on the result of an alpha scattering experiment performed by Geiger and Marsden. However, the first results on alpha scattering were obtained much earlier, during the time Rutherford was at McGill. In a paper Rutherford published in 1906 entitled “Retardation of the alpha ...
Raman spectroscopy is an efficient method to characterize the graphene structure. The technique gives distinctive features for pristine, damaged and even doped graphene. Nonetheless, especially when graphene is grown on a polycrystalline substrate, strong discrepancies may appear on the macroscopic scale. Moreover, in the case of plasma irradiation of graphene, it is essential to understand...
The quest to develop a fundamental understanding of the nuclear interaction is aided greatly through measurements made with complex, multi-detector systems. As these systems allow for both an increase in total efficiency due to greater angular coverage as well as correlation measurements in both time and space, the information which can be probed using these detectors is greatly increased over...
In any application where a radiation detector is utilized in a mixed radiation field, there is an inherent issue of separating the signal from the background. This research focuses on the separation of neutron and gamma-ray events in a liquid scintillator. The standard solution to this issue leverages the fact that the secondary particles generated in neutron and photon interactions are...
Graphene is an interesting system for condensed matter physicists because of many potential technological applications. It is interesting to theorists as an abelian strongly coupled system that has some of the interesting properties of QCD.
We are particularly interested in studying the effects of anisotropic strain of the graphene
lattice on the critical coupling, which determines the...
Superfluid neutron matter is a key ingredient in the composition of neutron stars. The physics of the inner crust is largely dependent on that of its
We present some analytic results that describe the gluon field, or glasma, that exists at very early times after a collision of relativistic heavy ions at proper time
The spherical Proportional Counter (SPC) is used in NEWS-G to search for low-mass Weakly Interacting Massive Particles (WIMPs). UV laser and Ar37 calibration data was previously taken at Laboratoire Souterrain de Modane (LSM) with a 1.35m diameter SPC filled with pure CH4 gas. In order to verify our understanding of the detector behaviour and the physics model we use, a simulation of the SPC...
The versatility of gamma-ray spectroscopy has given rise to its many applications, from quantification of trace elements in a sample to maintaining nuclear material safeguards. Depending on the application and gamma-ray detector, there is often a compromise made between detection efficiency and energy resolution. While characterizing or quantifying trace radionuclide concentrations in an...
Organic molecules capable of forming strongly bound self-assembled monolayers (SAMs) offer a promising route to surface modification and functionalization. Technological advances including the protection and stabilization of nanoparticles and the development of lab-on-chip sensors have been largely realized by the adsorption of alkanethiols. N-heterocyclic carbenes (NHCs) were recently...
Do we really need a hypothetical gauge boson, "X17", to explain the famous ATOMKI measurements? Or can there be some interplay between the theoretical and experimental effects? We show that the bump in the
The Hyper-Kamiokande (HK) experiment, a next generation underground experiment in Japan, will have a broad physics program, including long-baseline neutrino oscillation measurements using an upgraded 1.3 MW beam produced at J-PARC accelerator, following the successful T2K experiment. To achieve the designed goal, an accurate prediction of neutrino interaction rates on the water target at the...
As you know, first gravitational wave event GW150914(binary black hole) has been oberved by LIGO on Sep. 14, 2015. And most importantly, first binary neutron star coalescence event GW170817 has been observed with a signal noise ratio upto 33, which alows us to make constraints on axion field! Here, we first time use axion charged binary neutron star waveform model to give a constaint on axion field.
The existence of dark matter is ubiquitous in cosmological data, yet numerous particle detectors have been thoroughly looking for it without any success. For strongly interacting dark matter, the bounds from these experiments are actually irrelevant; as dark matter enters the atmosphere, it scatters and slows down, such that it has a much lower velocity than the detector threshold when it...
Superconducting transition-edge sensors (TESs) carried by x-ray telescopes are powerful tools for the study of neutron stars and black holes. Several methods, such as optimal filtering or principal component analysis, have already been developed to analyze x-ray data from these sensors. However, these techniques may be hard to implement in space. Our goal is to develop a...
The delivery of a polymer chain from the chamber of origin to the destination through a nano-scale pore (nanopore) is called polymer translocation. Transport of RNA and DNA inside and into cells, virus Injection, and drug delivery are only a few examples of biological processes that polymer translocation plays a key role in. Prior to translocation, however, the chain must first find the...
In response to the COVID-19 pandemic and the physical distancing requirements, high school classrooms in Quebec had to switch to a half in-person and a half-online attendance. With very few studies examining this education model at the high school level, this study aims to investigate the teacher and student response, as well as observe its impact on student engagement within the physics...
In our time, when problems of population growth, consumption demands and climate change are matters of daily concern, I want to mention some of the ethical problems that have confronted scientists. The fact that any discovery may turn out to have both wonderful and disastrous consequences has been discussed many times before.
The discovery of nuclear fission brought us both the atomic bomb...
QCD sum-rule calculations contain loop-integration divergences associated with composite operators in correlation functions that must be renormalized to obtain physical predictions. The standard approach to renormalization through operator mixing can present technical challenges in situations where the basis of operators becomes large (e.g., for multi-quark operators). The BPH renormalization...
DEAP-3600 is a dark matter experiment which uses liquid argon to search for spin-independent interactions of weakly interacting massive particles (WIMPs). The experiment has completed two WIMP searches using 4.44 and 231 live days with 3322 kg and 3279 kg of liquid argon, respectively. In addition to these two data sets, the detector has recorded WIMP search data from 2016-2020 and analysis of...
In any finite system, the presence of a non-zero permanent electric dipole moment (EDM) would require both parity (P) and time-reversal (T) violation. The standard model predicts a very small CP violation and consequently any observation of the EDM would imply physics beyond the standard model. Thus, EDMs have long been proposed as a way to test these fundamental symmetries. Experimental...
A neutrino (or an anti-neutrino) can interact with an entire nucleus coherently (this means that the target nucleus has to stay intact after the interaction) and produce a pion - we call such an interaction coherent pion production. The interaction can either be mediated by a Z boson (neutral current) or a W boson (charged current). This process is not well understood theoretically. ...
DarkSide-20k is a planned two-phase liquid Argon time-projection-chamber (LAr-TPC) for direct WIMP search. The S1 and S2 light from the 20 ton fiducial volume is detected with Silicon photomultipliers and digitized. Due to the expected data rate of hundreds of MB/s it is impractical to record full waveform data continuously like in the smaller DarkSide-50 experiment, instead complex filtering...
A central problem in quantum error correction is to develop good codes. This problem is often reduced to maximizing the number of logical qubits
In this work, we use...
Entropy stabilized oxides, containing a large number of different elements, exhibiting simple crystal structure have shown interesting properties such as colossal dielectric permittivity, superionic conductivity and enhanced exchange coupling.
To study how the ionic character can be tuned by using different mixtures of oxides, the effective charge for the rocksalt structure high entropy oxide...
Wide field imaging of the retina at the rear of the eye is recommended yearly for those with diabetes to screen for sight threatening changes. We and others have shown that amyloid protein deposits in the retina appear early in Alzheimer’s disease (AD) and predict the severity of amyloid in the brain.
We wish to optimize a scanning laser instrument to image the retina for screening both...
With the proliferating global concern for environmental issues, there is a growing demand for a renewable, cost-effective, and sustainable electronics [1]. Carbon-based composite nanomaterials (i.e. graphene, graphene oxide, carbon nanotubes, carbon quantum dots etc.) are a promising candidate for such applications due to their tunable electrical, optical, and mechanical properties [2]. Most...
Contamination from radioisotopes are a major background source in rare-event experiments such as searches for dark matter and neutrinoless double beta decay searches. A common internal source of radioactive backgrounds that creates many challenges for these experiments is radon and its progeny. As a noble gas, it can easily enter the innermost part of the active target through diffusion, and...
An ab initio nuclear many-body calculation needs the nucleon-nucleon (NN) and three-nucleon (3N) matrix elements as an input. The NN matrix elements can be prepared in a sufficiently large space, while the 3N matrix elements are significantly limited. Due to the limitation, it is challenging to obtain reliable results for the system heavier than
En 1781, le géologue français Déodat de Dolomieu visite le sud-est de la Sicile afin d’étudier les volcans éteints de la région du Val di Noto. Les résultats de ses recherches furent présentés dans un mémoire, publié en 1784, paru dans les Observations sur la physique, sur l'histoire naturelle et sur les arts par François Rozier (1734-1793). Dans ce mémoire, Dolomieu expose notamment, en...
Precision measurements of neutrino interactions being pursued in the current Super-K detector, the next-generation Hyper-K detector, and its Intermediate distance Water Cherenkov Detector (IWCD) necessitate improved calibrations. Photogrammetry will be used to reduce the position uncertainty on the photomultiplier tubes (PMTs) and calibration source locations within the detector. The...
Changes brought about by the COVID-19 pandemic have challenged educators at all levels. While the University experience has not been ideal, our classes benefited from platforms like Zoom already being in place and virtual labs already having been available to us. Elementary and secondary school students have had to overcome much more uncertainty and more severe obstacles. The need for outreach...
SnIP is an exciting new quasi-1D van der Waals semiconductor with a unique double-helix structure at the atomic scale that shows promise as a new material for flexible electronics. However, due to the high resistivity of as-grown SnIP its true potential is not clear. In this work, we study SnIP-nanowire thin films using time-resolved THz spectroscopy (TRTS), a powerful ultrafast optical tool...
SNO+ is a multipurpose neutrino experiment located approximately 2 km underground in SNOLAB, Sudbury, Canada. The second phase of the experiment is underway and consists of filling the detector with 780 tonnes of Linear Alkyl Benzene (LAB) scintillator. The fill is expected to be completed spring 2021. During this partial fill stage a number of external calibration campaigns have been...
It has long been known that most of the matter in our Universe is dark. The direct detection of dark matter particle interactions is one of the most important topics in particle physics - a positive measurement would provide unambiguous evidence of the particle nature of dark matter in the Universe. In this talk we will present an overview of the phased approach to dark matter searches by the...
Abstract coming soon.
While group work is common in most introductory physics labs, research in physics education has found that students' experiences in those groups are not necessarily in common. I'll discuss our recent work evaluating how students participate in the hands-on aspects of physics labs, particularly illuminating imbalances between men's and women's participation. I'll also describe how nuances in...
In this overview I'll present a selection of recent machine applications to event reconstruction and data analysis across the subfields of experimental particle physics. Strategies for treatment of experimental data and design of machine learning algorithms will be discussed. I will give a personal perspective on potential future particle physics applications of machine learning, including...
The state of a quantum system evolves according to the Schrödinger equation. Often, one is interested in the behaviour of parts of a whole system only. Such parts are called open quantum systems, as they exchange energy, matter, information with their surroundings. The dynamics of open systems is very complicated. They are a central topic of research in many theoretical and applied fields of...
H2 continues to provide fundamental insights into the mechanisms of intense light-matter interactions [1]. Recently, there has been significant interest in so-called light-induced conical intersections (LICI) that arise from the angle dependence of the single-photon coupling of electronic states. Analogously to regular conical intersections, electronic and nuclear motions are strongly coupled...
The Electron−Ion Collider (EIC) is a major new collider facility to be built on Long Island, New York, by the end of the current decade. At the EIC, polarized electrons will collide with polarized protons, polarized light ions, and heavy nuclei at luminosities far beyond what is presently available. The facility will answer several fundamental questions central to the understanding of atoms,...
Optical tweezers are an essential tool in a broad range of fields, from biophysics to soft-matter and statistical physics. Using a feedback-based trap that can produce complex, time-dependent potential landscapes, we can experimentally realize situations in thermodynamics, such as finite-time bit-erasure, that were previously only thought experiments. To obtain quantitative results, however,...
Water Cherenkov Test Experiment (WCTE) is a proposed experiment at CERN that will study the response of a small water Cherenkov detector in hadron, electron, and muon low momentum beams. The aim of the experiment is to test new photosensor technologies such as multi-PMT modules and apply calibration techniques with known particle fluxes to validate
Vertically stacked heterostructures of two-dimensional materials provide a platform for realizing novel electronic states due to proximity effects. In particular, moiré patterns in two-dimensional material heterostructures have been shown to create flat bands that favor the occurrence of correlated electronic states. In this work, we use scanning tunneling microscopy and spectroscopy to study...
The non-adiabatic coupling of nuclear and electronic degrees of freedom underlies many fundamental processes in Nature, including solar energy conversion and photosynthesis. The formation of electronic coherences by nuclear motion is a new aspect of such dynamics and requires new measurement techniques and methods of analysis. We will discuss Ultrafast Time-Resolved Xray Absorption and...
The creation and annihilation of particles is a fundamental feature of relativistic quantum fields. A famous example of this is provided by Schwinger’s 1951 prediction that the vacuum is unstable to particle-antiparticle production if a static electric field is applied to it. In this talk we examine the classical field limit of Schwinger pair production by mapping the Klein-Gordon equation...
In the search for astrophysical neutrinos, neutrino telescopes instrument large volumes of clear natural water. Photomultiplier tubes placed along mooring lines detect the Cherenkov light of secondary particles produced in neutrino interactions, and allow us to search for possible neutrino sources in the sky. The P-ONE experiment proposes a new neutrino telescope off the shore of British...
Liquid Argon (LAr) is used as a target material by many WIMP dark matter search experiments for its high light-yield and excellent background rejection capability. LAr produces scintillation light at 128nm, which conventionally requires a wavelength shifting (WLS) material to be detected by photomultiplier tubes. Tetraphenyl-butadiene (TPB) is the WLS material of choice for most LAr detectors,...
In optics, caustics are bright, sharp lines and shapes created by the natural focusing of light. Some examples include rainbows, the wavy lines on the bottom of swimming pools and the patterns produced by gravitational lensing. The intensity at a caustic diverges in the classical ray theory, but can be smoothed by taking into account the wave nature of light. In this work we consider a new...
Two dimensional (2D) materials are tempting for nano-electromechanical systems (NEMS), as they are atomically thin, have low mass and high flexibility. 2D materials have tunable optical and electronic properties, and can display other exotic properties, such as superconductivity. Over the last decade, scientists have begun stacking 2D materials into heterostructures that have desirable...
Laser-induced rotational wavepacket of hydrogen molecules has been experimentally observed in real time by using two sequential 25-fs laser pulses (pump-probe scheme) and a COLTRIMs spectrometer. By measuring the time-dependent yield of the above-threshold dissociation and the enhanced ionization of the molecule, we observed a few-femtosecond time delay in between the two dissociation pathways...
Gravitational tidal forces conceal very interesting effects when combined with the extended nature of the wavefunction of a freely-falling quantum particle. The reason being that inertial properties of the particle get then mixed with the gravitational effects in such a way that, as in classical mechanics, the ratio between the gravitational mass and the inertial mass emerges. The equivalence...
Light possessing a broadband frequency spectrum, also known as a supercontinuum (SC), has facilitated a plethora of applications such as optical coherence tomography (OCT) and optical communication. In general, these spectra are produced by propagating narrow-band optical pulses through a highly nonlinear medium. Photonic crystal fibers (PCFs) are often used as the nonlinear medium for SC...
Liquid xenon (LXe) is frequently employed to build detectors for rare event searches due to many of its advantageous properties including high stopping power, high ionization and scintillation yields, and relatively high cryogenic operating temperature. Time projection chambers (TPC) with LXe allow for 3D event topology reconstruction and identification which is important for reducing...
Introduction: Graphene is a promising nanomaterial for chemical sensors or biosensors, but functionalization of its surface is usually necessary to ensure specific interactions with the chosen analyte. Among functionalization strategies, covalent adducts are most likely to ensure stability of the functionalization during multiple flow cycles. In particular, aryldiazonium salts are known...
DEAP-3600 is a sensitive single-phase liquid-argon detector of non-baryonic dark matter at SNOLAB. WIMP-nucleon scattering is distinguished from electromagnetic events by pulse shape discrimination (PSD) in the argon. Nuclear recoils, which have high ionization density, preferentially excite a singlet argon dimer state which decays via VUV emission in nanoseconds. Electromagnetic events, which...
Combining quantum and classical degrees of freedom provides a useful approximation in many practical applications. Examples include the study of quantum particles in a classical external potential (textbook quantum mechanics), or quantum field theory on a classical curved background. In these examples, only the classical affects the quantum, but not the other way around. If these...
Optical parametric amplifiers deliver intense ultrashort pulses with broadly tuneable frequencies, useful for strong field physics, high harmonic generation, and attosecond experiments. Currently, this nonlinear amplification scheme relies on the second order nonlinearity,
This talk aim to discuss the scattering of particles on quantum superposed states. The fact that one of the initial states is in a superposition implies that the plane wave approximation is not valid anymore which is what we usually do. This will lead to the introduction of Wigner function and a formalism to describe this situation.
We will apply this new formalism to the question of...
Silicon Photo-Multipliers (SiPMs) have emerged as a compelling photo-sensor solution over the course of the last decade. SiPMs consist of an array of tightly packed microcells with each microcell acting as an avalanche photodiode that can behave in the Geiger mode regime when the device is reverse biased above a threshold voltage (breakdown voltage). In contrast to the widely used...
Several parallels can be drawn between the perovskite iridate Sr
Attosecond science is a relatively new research field founded on high-harmonic generation (HHG) in atomic and molecular gases, which has recently transitioned to experiment in 3-dimensional solids. Most of the physics underlying attosecond pulse emission from 2-dimensional semiconductors is unknown. Following years of research focusing on HHG in bulk semiconductors, this project focuses on the...
On behalf of the TITAN collaboration
Nuclear-physics studies are probing into nuclear structure, nucleosynthesis and fundamental interactions, for which high precision and accurate mass measurements are critical inputs. TRIUMF’s Ion Trap for Atomic and Nuclear science (TITAN) facility employs the Measurement Penning Trap (MPET) to measure masses of exotic nuclei ~1x10-8 accuracy. To improve...
DEAP-3600 is a low-background, single-phase liquid argon (LAr) direct detection experiment looking for nuclear recoils from WIMP dark matter, operating 2 km underground at SNOLAB (Sudbury, Canada). The detector consists of 3279 kg of LAr contained in a spherical acrylic vessel. LAr is an excellent scintillator, transparent to its own scintillation light. Photomultiplier tubes detect the...
According to the laws of thermodynamics, a closed many-body system is expected to follow a chaotic evolution and reach a state of thermal equilibrium. The issue arises when one asks for a quantum picture. Indeed quantum mechanics strictly prohibits chaotic dynamics, and some quantum systems have been discovered to resist thermalization.
To solve this paradox, entanglement is believed to be a...
Quantum confinement and manipulation of charge carriers are critical for achieving devices practical for various quantum technologies. 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 this talk, we present...
There is a large body of research suggesting that marginalized students hold negative attitudes and beliefs towards physics that manifest in high-school. These perceptions of physics can negatively impact student learning and have been repeatedly associated with the gender gap in performance in introductory physics courses at the university level. Many universities offer multiple streams of...
Potassium-40 (
Among the outstanding questions of particle physics, proof of the existence of a magnetic monopole is still one of great interest. Not only would the observation of a magnetically charged particle grant symmetry between electric and magnetic fields in Maxwell’s equations, but it would also explain the quantization of the electric charge. We are searching for TeV-mass magnetic monopoles in the...
Recent decades have seen many advances towards gender parity in the fields of science, technology, engineering, and mathematics (STEM). But while biology, chemistry, and mathematics have all achieved >40% female undergraduate enrollment, there remains a significant dearth of women in physics and engineering. Both disciplines have plateaued at ~20% women since the mid-nineties. This issue,...
NEWS-G is a direct detection dark matter experiment specializing in low mass (sub ~1 GeV) WIMP (Weakly Interacting Massive Particles) searches. NEWS-G uses spherical proportional counters (SPCs) - gas-ionization detectors capable of observing signals from single-electrons through the use of a small (~1 mm radius) high-voltage anode sensor at their centre. With the increasingly complex nature...
Polarimetry is a wildly-used measurement technique for inferring properties of a sample by observation of the changes in the polarization of the light transmitted or reflected by the sample. One of the impediments to wider use of the technique, especially in bio-medical applications such in-vivo biopsy, is that it can require very high laser intensities, leading to collateral tissue damage. ...
In this talk I will provide motivation for determining the neutron radius of heavy nuclei, and why PREX II and CREX provide theoretically clean measurements in lead-208 and calcium-48. This will include a description of parity-violating electron scattering experimental design and efforts to minimize the systematic uncertainties. The neutron skin measurement on lead provides information about...
In this talk, we show that any non-constant quantity defined on density matrices that is additive on tensor products and invariant under permutations cannot be "more than asymptotically continuous."The proof is a direct consequence of generalizing a protocol for embezzling entanglement. Joint work with Andrea Coladangelo.
Bell nonlocality describes a manifestation of quantum mechanics that cannot be explained by any local hidden variable model. Its origin lies in the nature of quantum entanglement, although understanding the precise relationship between nonlocality and entanglement has been a notorious open problem. In this talk, I will describe a resolution to this problem by developing a dynamical framework...
SuperCDMS (Super Cryogenic Dark Matter Search) is an experiment for the direct detection of dark matter that uses cryogenic silicon and germanium detectors which can measure energy depositions as low as a few eV. The ionization yield for nuclear recoils is the ratio of the number of electron-hole pairs produced by a nuclear recoil over the number of electron-hole pairs produced by an...
The quantum vacuum has long been known to be characterized by field correlations between spacetime points. These correlations can be swapped with a pair of particle detectors, modelled as simple two-level quantum systems (Unruh-DeWitt detectors) via a process known as entanglement harvesting. We study this phenomenon in the presence of a rotating BTZ black hole, and find that rotation can...
Concern about the inclusion and fair treatment of all individuals wishing to pursue a degree in science is perhaps stronger now that it has ever been. Examples include studies related to pay equity, conferences for women in STEM disciplines, and NSERC’s new guidelines regarding Equity, Diversity, and Inclusion. The situation is regarded as particularly acute in Physics, where males still...
We carry out the first investigation of the entanglement and mutual information harvesting protocols for detectors moving on freely falling trajectories that cross the horizon of a black hole. We consider two pointlike Unruh-DeWitt detectors in different combinations of free-falling and static trajectories in (1+1)-dimensional Schwarzschild black hole spacetime and compare the results. We...
We present a new efficient calculation to propagate cosmic ray muons from the surface of the Earth to deep underground laboratories, allowing us to look at the physics and performance of various models of high-energy cosmic rays. The evolution of cosmic rays in the Earth's atmosphere is computed with MCEq (Matrix Cascade Equation), taking into account different combinations of primary and...
Quantum field theory is completely characterized by the field correlations between spacetime points. In turn, some of these can be accessed by locally coupling to the field simple quantum systems, a.k.a. particle detectors. In this work, we consider what happens when a quantum- controlled superposition of detectors at different space-time points is used to probe the correlations of the field....
Hadronic structure is poorly understood as the properties of constituent quarks and gluons (e.g. spin, mass) do not explicitly add up to the properties of hadrons. The form factor describes the transverse position of partons inside a hadron. Perturbative QCD (pQCD) uniquely predicts the form factor at very high Q2, which is experimentally inaccessible. Different non-perturbative QCD models...
The DEAP-3600 experiment (Dark matter Experiment using Argon Pulseshape discrimination) at SNOLAB in Sudbury, Ontario is searching for dark matter by recording their interactions with a liquid argon target. It is designed to detect nuclear recoils induced by the elastic scattering of weakly interacting massive particles (WIMPs) - a leading candidate for dark matter.
Minimizing backgrounds...
The
This talk will go over the different skills that physicists will acquire during their undergraduate and graduate studies. An overview of the different career paths will be given as well as tricks to network. Finally, we will discuss salaries and preparation for interviews.
Cette conférence passera en revue les différentes compétences que les physiciens acquerront au cours de leurs...
