COVID-19 information for PI Residents and Visitors
We invite applications to "Women in Physics Canada", a three day conference which will take place from Tuesday, July 19 to Thursday, July 21, 2011 jointly at Perimeter Institute and the Institute for Quantum Computing, Waterloo, Ontario. This conference, aimed at undergraduates and early graduates, is intended to provide support to young women in physics and astrophysics, and to encourage them to continue in a career in science. The main component of the conference will be student presentations and we invite participants from all areas of physics, astrophysics and astronomy to present their research. There will also be several keynote lectures, opportunities for discussions with more senior physicists, and interactions with our invited speakers and local researchers.
We welcome participants at all stages of their career, however as the event is intended to benefit students, all contributed talks will be given by student participants. Students who have not yet had the opportunity to complete a research project are also welcome. The conference will provide a forum for young female physicists to develop both presentation and informal discussion skills, and will also facilitate the creation of informal support networks between peers. In so doing, this event will help women physicists at an early stage of their career develop the skills and confidence essential to their continuing success.
The under-representation of Women in Science has seen much research in recent years, the results of which are still inconclusive. Physics fares even worse than other sciences: in Canada, around 20% of physics degrees, at undergraduate and postgraduate level, are awarded to women. By focusing on skills important for any young physicist, as well as encouraging students to make connections with peers, we hope that this conference can make a difference to young female physicists, now and as their careers progress. The schedule will also include a panel discussion, so that participants can hear directly from more senior women about what a career in physics entails.
Invited Guests
Panel Participants
Aida Ahmadi, University of Calgary
Khulud Almutairi, IQIS University of Calgary
Razieh Annabestani, Institute for Quantum Computing
Amanda Bishop, University of New Brunswick Saint John
Golnoosh Bizhani, University of Calgary
Chloe Bureau-Oxton, Sherbrooke University
Fang Chen, McGill University
Hillary Dawkins, University of Guelph
Monika Deivat, University of Calgary
Lidia del Rio, ETH Zurich
Miriam Diamond, Carleton University
Sara Ejtemaee, Simon Fraser University
Xiaoxia Fan, University of Waterloo
Marjorie Gonzalez, University of British Columbia
Chen He, McGill University
Catherine Holloway, Institute for Quantum Computing
Natasha Holmes, University of British Columbia
Fayruz Huq, York University
Biljana Indovski, Brock University
Nikta Javanfar, Queen's University
Stacey Jeffery, Institute for Quantum Computing
Ann Kallin, University of Waterloo
Johanna Karouby, McGill University
Jiae Kim, University of British Columbia
Shelby Kimmel, Massachusetts Institute of Technology
Madeline MacGillivray, Acadia University
Chloe Malbrunot, UBC/TRIUMF
Andrea Marshall, University of British Columbia
Mercedes Martinson, University of Saskatchewan
Anna McCoy, Perimeter Institute
Emma McKay, University of Waterloo
Corey Rae McRae, University of Western Ontario
Corina Nantais, Queen's University
Yomna Nasser, University of Waterloo
Brittini Ogden, Wilfrid Laurier University
Jane Panangaden, McGill University
Miok Park, University of Waterloo
Cathryn Parsons, Acadia University
Aleksandra Petrova, Kasan (Volga Region) Federal University
Deanna Pineau, University of Victoria
Sepiedeh Pirasteh, Brock University
Vanessa Punal, Oakland University
Shohreh Rahmati, University of Lethbridge
Sophie Rochette, Sherbrooke University
Hoimonti Rozario, University of Lethbridge
Tamara Rozina, University of Waterloo
Maitagorri Schade, Perimeter Institute
Shivani Sharma, Ryerson University
Marisa Smith, Mount Allison University
Erin Stephenson, University of Guelph
Maryam Taheri, Brock University
Francesca Vidotto, Centre de Physique Thorique Marseille
Di Wan, University of Calgary
Judy Wang, McGill University
Lucy Liuxuan Zhang, University of Toronto
Aida Ahmadi, University of Calgary
Determination of Total C18O Column Density in Orion KL
The large number of high-energy rotational lines of C18O, available via the Herschel Space Observatory, provides an unprecedented ability to model the total C18O column density in hot cores. Using the emission from all the observed lines (up to J=16-15) we use an automated algorithm to model all transitions simultaneously. Under Local Thermodynamic Equilibrium (LTE) assumptions and knowledge of source size, centroid velocity and line width, the model determines the values for total C18O column densities in 4 separate line-of-sight components of Orion KL known as the Extended Ridge, the Outflow/Plateau, the Compact Ridge, and the Hot Core. These values are determined to be: 2.5 X 10^16, 5.9 X 10^16, 1.8 X 10^16, and 6.0 X 10^16 cm^(-2) respectively. We also explain the difficulties in using the said algorithm to model optically thick molecules such as CO which require non-LTE modeling.
Khulud Almutairi, IQIS University of Calgary
Generating Two-Photon Entangled States in a Driven Two-Atom System
We describe a mechanism for a controlled generation of a pure Bell state with correlated atoms that involve two or zero excitations. The mechanism inhibits transitions into singly excited collective states of a two-atom system by shifting them from their unperturbed energies. The shift is accomplished by the dipole-dipole interaction between the atoms. The creation of the Bell state is found to be dependent on the relaxation of the atomic excitation. When the relaxation is not present or can be ignored, the state of the system evolves harmonically between a separable to the maximally entangled state. We follow the temporal evolution of the state and find that the concurrence can be different from zero only in the presence of the dipole-dipole interaction. Furthermore, in the limit of a large dipole-dipole interaction, the concurrence reduces to that predicted for an X-state of the system. A general inequality is found which shows that the concurrence of an X-state system is a lower bound for the concurrence of the two-atom system. With the relaxation present, the general state of the system is a mixed state that under a strong dipole-dipole interaction reduces the system to an X-state form. We find that mixed states admit of lower level of entanglement, and the entanglement may occur over a finite range of time. A simple analytical expression is obtained for the steady-state concurrence which shows that there is a threshold value for the dipole-dipole interaction relative to the Rabi frequency of the driving field above which the atoms can be entangled over the entire time of the evolution.
Neta Bahcall, Princeton University
The Dark Side of the Universe
What is the Universe made of? Recent observations suggest surprising results: not only most of the matter in the Universe is dark and unconventional but, more surprisingly, the major component of the Universe may be in the form of 'dark energy' -- a form of energy that opposes the pull of gravity and causes the expansion of the universe to accelerate. By combining recent observations of clusters of galaxies, distant supernovae, and the cosmic microwave background, we find evidence for a Universe that has only 5% 'normal' baryonic matter, 20% non-baryonic dark matter, and 75% 'dark energy'. The observations suggest a Universe that is lightweight, with only 25% of the critical mass-density needed to halt the Universal expansion, and a geometry that is flat with no space curvature. The observations of the dark side of the Universe and their implications will be discussed.
Chloe Bureau-Oxton, Sherbrooke University
Introduction to Spin Qubits in Lateral Quantum Dots
A quantum computer is a computer fabricated using quantum bits (qubits) that uses the quantum properties of matter (entanglement, superposition of states, etc.). Such a computer would allow certain calculations to be done exponentially more quickly than with a classical computer. An electron in a quantum box constitutes a perfect two-level system and can thus be used as a qubit. In my talk, I will give an introduction to lateral quantum dots, their fabrication process and how they can be used as qubits.
Melanie Campbell, University of Waterloo
A Physicist’s View of the Eye
Melanie will discuss how she has and collaborators have applied physics techniques to advance the understanding of the optics of the eye, and to develop novel diagnostic and therapeutic approaches for eye diseases. Her work includes the application of inverse methods used to characterise optical fibres, waveguide theory applied to cone photoreceptors, sinusoidal analysis of circadian rhythms in the eye, adaptive optics, confocal and polarisation imaging used to improve images of the rear of the eye, characterisation of deposits by atomic force microscopy and drug excitation by two photons as a therapy for eye disease.
Using an Abel integral inversion technique applied in optical fibres, Campbell measured for the first time, the gradient refractive index variation in the crystalline lens of the eye. She and her collaborators demonstrated that this distribution can be modified by visual experience. Campbell and her collaborators have also shown that the optical quality of the lens varies with age and that the progressive loss of near vision is lens based. These findings inspired a new design for an IOL lens which replaces the living lens during cataract surgery.
In another example, adaptive optics, originally developed for astronomy, offers a powerful tool for localizing light within the eye. In turn, this has resulted in the correction of the optical imperfections of the eye, giving images of structures at the rear of the eye with improved resolution and contrast.
In addition, adaptive optics can precisely localize light stimuli for therapeutic purposes within the eye. The precise localization of light energy in other at the retina is limited by the optics of the eye. Adaptive optics may enable precise light based therapies in the crystalline lens and retina of the eye.
Fang Chen, McGill University
QCD Confinement at Finite Chemical Potential and the Gravity Dual
Lidia del Rio, ETH Zurich
Thermodynamics and Information
Thermodynamics is, at heart, a probabilistic theory about the state of physical systems. Traditionally, however, our knowledge of systems is modelled implicitly: for instance, it is often assumed that we only have access to a few macroscopic parameters, like the temperature, energy, or volume of a gas, and that all states satisfying those parameters are equally likely.
Another example is Maxwell's demon, an apparent violation of the second law: a demon operates the trapdoor between two boxes filled with a gas at the same temperature. He lets fast particles fly to the right box, cooling the left container and heating the right one at no work cost. The paradox comes from ignoring the demon's memory, a system where he stores his information about the speed of the particles, which has finite capacity. Eventually, he will have to erase his memory, an irreversible operation that costs him work.
Classical and quantum information theory have given us tools to model knowledge explicitly: we use them to analyse the security of cryptographic protocols, or how much information can be sent through a noisy channel, for example. In this talk, I will explore what happens when we apply information-theoretical tools to thermodynamics. In particular, I will discuss the implications of having quantum information about a physical system, with the example of erasure of information.
Monika Deivat, University of Calgary
On the Existence of a Residue Entangled State in eLOCC Transformations
Quantum entanglement is a valuable resource in the field of quantum information science and allows one to accomplish many information processing tasks. In quantum transformations an entangled state A can be converted to another state B through local operations assisted by classical communication (LOCC). It has also been demonstrated that there exist entangled states A, B, C such that state A cannot be converted to a state B, but A otimes C can be converted to B otimes C by LOCC, where C is a suitably chosen entangled state acting as the catalyst. This is known as entanglement assisted LOCC or eLOCC. I will show that for certain A and B it is possible to obtain an extra entangled state R, called the residue entangled state in an eLOCC transformation. That is to say A otimes C can be converted to B otimes R otimes C even though A cannot be converted to B by LOCC. I will discuss the necessary and sufficient conditions for such a transformation to occur.
Miriam Diamond, Carleton University
Exploring Dark Matter in a Leptophilic Two-Higgs-Doublet Model
A recent analysis of gamma rays from the centre of our galaxy has provided possible evidence for a dark matter annihilation signal, with the dark matter taking the form of low-mass WIMPs annihilating predominantly to taus. We study an extended Higgs model proposed to yield such a dark matter candidate. Scanning over parameter space in this model, we find suitable areas that feature fairly little fine-tuning. In favoured areas, the cross-sections for invisible decays of neutral Higgses are predicted to be too low for detection atcolliders. However, dark matter direct detection experiments are currently becoming relevant for constraining parameter space in the model.
Marjorie Gonzalez, University of British Columbia
Spatial Analysis of Positron Emission Tomography Images using 3D Moment Invariants
3D moment invariants (3DMIs) are mathematical spatial descriptors designed to be invariant to scaling, translation and rotation. We propose to characterize the spatial distribution of positron emission tomography (PET) images using 3DMIs. We have used 3DMIs to characterize the spatial distribution of PET brain images recorded from subjects with Parkinson's Disease (PD) and healthy controls. 3DMIs were found to accurately describe the 3D texture of PET images despite changes in the size and orientation of the participating subjects in the PET scanner. In addition, we were able to find differences in the 3DMIs of PD patients distinct from those of healthy volunteers. These changes suggest that disease-related variations in the spatial distribution measured using PET can be quantitatively described with the proposed method. Therefore, this method shows great promise to extract additional information from PET data with a wealth of potential applications to disease diagnosis, staging, treatment assessment and more. The quantification of the observed disease-related changes for PD subjects is currently under way.
Alina Chen He, McGill University
Searching for Neutron Stars in Disguise with NASA's Chandra X-ray Observatory
Neutron stars are the collapsed cores of massive stars that went under supernova explosions. They are found with high surface magnetic fields, rapid but steady rotation and high density comparable to that inside an atomic nucleus. In the past 20 years, many different classes of neutron stars have been discovered. One of the most enigmatic classes of neutron stars is the compact central objects (CCOs). Only seven of them have been discovered and their emission process are still not well understood. Three of them have magnetic field estimates which are found to be significantly lower than those of the other neutron stars of comparable age. I will describe our project searching for more of these mysterious objects with NASA's Chandra X-ray Observatory. We compiled a list of eleven nearby weak-field neutron stars to look for CCO-like X-ray emission. Chandra carried short observations of six of them and no x-ray emission was found. The physical implications of the results will be discussed.
Catherine Holloway, Institute for Quantum Computing
Quantum Key Distribution Over Active Telecom Fibres
Quantum Key Distribution is a form of public-key cryptography where the security comes from the unique properties of quantum mechanical systems: entanglement and the no-cloning theorem, rather than computational complexity. With increased adoption of fibre optic networks, it may be possible to implement QKD in parallel with classical data traffic. Many research projects have demonstrated QKD over fibre optic networks at the same wavelengths as existing network traffic. These projects require sophisticated noise cancellation due to wave mixing between quantum and classical signals, as well as having to use complex non-silicon based photodiodes. Our research uses lower wavelengths for QKD over active telecom fibres to avoid these problems. Entangled lower-wavelength photons are combined with telecom wavelength laser signals carrying a large amount of traffic, and passed through single mode telecom fibres. We show that data bandwidth usage has a negligible effect on the quantum bit error rate (QBER) and visibility for distances up to 6km. We find key rates of 61 bits per second with QBER rates of 10% at 6km. This research demonstrates the simplicity and applicability of QKD to existing fibre optic infrastructure in corporate, government, and academic campuses.
Natasha Holmes, University of British Columbia
Physics Education Research: Helping Students Become Better Scientists
Physics Education Research (PER) is a blossoming subfield of physics that is changing the way students become physicists. Our research involves the transformation of the lab portion of a first-year enriched physics course through the implementation of “invention activities:” discovery-learning activities that ask students to “invent” a solution to a problem before being taught the expert solution. The combination of invention activities and tell-and-practice methods has been shown to lead to better student learning and performance on transfer tasks, as compared to tell-and-practice methods alone (Roll, Aleven & Koedinger, 2009; Schwartz & Martin, 2004). In addition, scaffolding invention activities using domain-independent metacognitive prompts can support students through the invention process, leading them to attend to more features of the domain and reason at a deeper level (Roll, Holmes, Day & Bonn; submitted). Our current study further investigates this theory by expanding the treatment across a four-month term and using faded levels of scaffolding. Using interactive learning environments (ILE), five inventions in the domains of statistics and data-analysis were given to students and various assessments were administered to measure performance on domain-level knowledge and “invention skills.” I will present preliminary results from this and previous studies.
Biljana Indovski, Brock University
Structural, Electronic, Magnetic, and Thermal Properties of Pb2-xLaxCrO5
Pb2CrO5 have received considerable interests due to their potentials applications in UV radiation measuring devices, visible and UV light photodetectors. In this research we are examining the structural, electronic, magnetic, and thermal properties of polycrystalline Pb2-xLaxCrO5. Samples have been prepared using a solid state solution technique. The temperature dependent magnetic measurements reveal a transition in the Pb2CrO5 and La doped samples near 300 K. To understand the possible origin of such transition, we measured thermal properties using Differential Scanning Calorimetry (DSC) technique. These results reveal an endothermic transition close to 285 K in the parent sample and in La doped sample. We have also measured the temperature dependent resistance in 300K-900K range.
Nikta Javanfar, Royal Military College of Canada
Detection of Magnetic Fields in Cool Supergiants
Magnetic fields of stars can provide insight on their structure and evolution. These magnetic fields can be detected by exploiting the Zeeman effect. The theory behind detection and the method of Lease Squares Deconvolution will be described and preliminary results will be presented.
Stacey Jeffery, Institute for Quantum Computing
A Brief Introduction to Quantum Cryptography
By exploiting the properties of quantum mechanical systems, two parties can achieve cryptographically secure communication in a manner not possible in a purely classical world, through the process of quantum key distribution. In this talk, I will briefly introduce the field of cryptography and explain one of the most fundamental applications of quantum mechanics to cryptography.
Johanna Karouby, McGill University
Radiation Instability for a Matter Bounce
In this talk I will discuss an alternative to infation models, namely non singular bouncing models.Their advantage is to supress both the transplanckian problem and the big bang singularity. It also gives a scale invariant power spectrum in the case of amatter bounce.First we will study a toy model, the non singular matter bounce. Then we will try to see what is the effect when we add upradiation through a gauge fields. To do that we add up a coupling term between the scalar fields and the gauge fields to see if it destroys the bounce or not.
Vicky Kaspi, McGill University
Neutron Stars and Fundamental Physics
Neutron stars are collapsed remnants of massive stars. One form of neutron star, pulsars, produce clock-like radio pulses, a result of their rotation combined with a misalignment of their rotation and magnetic axes. These pulses can be used in a variety of experiments in fundamental physics, including tests of gravity theories, constraining the properties of supranuclear density matter, and gravitational wave detection. In this talk, I will describe pulsar properties and explain how the above experiments are carried out, as well as show interesting recent results.
Jiae Kim, University of British Columbia
Neutrino Mass and Oscillation
In the standard Model, neutrinos are massless. But now we know that is not true any more. Neutrino has mass even though it is too small. And it leads neutrino flavor mixing. In other words, one flavor neutrino can transform to the other flavor neutrino. I will give theoretical back ground and brief idea how to measure this phenomena in real experiment.
Shelby Kimmel, Massachusetts Institute of Technology
Super-polynomial Speed-up for a Quantum Computer on Boolean Trees
We can prove that for certain problems, quantum computers do better than classical computers. I will introduce the query complexity framework, which lets us compare classical and quantum computers, and then describe a problem where quantum computers do better than classical. The problem I will discuss is evaluating boolean trees with a promise on the input.
Chloe Malbrunot, University of British Columbia, TRIUMF
Measurement of the Pion Branching Ratio at TRIUMF : A Sensitive Probe in the Search for New Physics
Study of rare decays is an important approach for exploring physics beyond the Standard Model (SM). The branching ratio of the helicity suppressed π → eυ decay, is one of the most accurately calculated decay process involving hadrons and has so far provided the most stringent test of the hypothesis of electron-muon universality in weak interactions. The branching ratio has been calculated in the SM to better than 0.01% accuracy to be R = 1.2353(1).10^4 .The PIENU experiment at TRIUMF, which started taking physics data in September 2009, aims to reach an accuracy five times better than the previous PSI and TRIUMF experiments so as to confront the theoretical calculation at the level of 0.1%. If a deviation from the SM branching ratio is found, “new physics” beyond the SM, at potentially very high mass scales (up to 1000 TeV), could be revealed. Alternatively, sensitive constraints on hypotheses can be obtained for pseudoscalar or scalar interactions, or on the mass and couplings of heavy neutrinos.So far, around five millions pion to electron decay events have been accumulated by the PIENU experiment. Data taking will continue in 2011 to increase the statistics to the 10^7 level.The presentation will outline the physics motivations, describe the apparatus and techniques designed to achieve high precision and present the status of the analysis.
Fotini Markopoulou, Perimeter Institute
Creating Spacetime
Our understanding of the physical world at the most fundamental level is based on two theories: quantum theory and general relativity. They are impressively successful but only when each is considered on its own. In situations where both play a role, we are reduced to puzzles and absurdity. Hence the search for a quantum theory of gravity, the currently missing theory that will work sensibly in exactly these situations. To the great frustration of researchers in this field, candidate quantum theories of gravity tend to produce more puzzles instead of answers. We shall take a tour of some of the problems, focusing on the role of spacetime and causality. We will consider the possibility that spacetime did not always exist but is instead emergent and explore how one can create a spacetime from a world with no notion of "here" and "there".
Mercedes Martinson, University of Saskatchewan
Density Functional Theory: A New Computational Approach for XAS of Solids
Anna McCoy, Perimeter Institute
Gamma Ray Bursts and the Principle of Relative Locality
Corey Rae McRae, University of Western Ontario
Exploring the Viscoelastic Properties of PAA Phantoms
A gel that has similar thermodynamic properties to human tissue is necessary for determining the safety of implanted medical devices during magnetic resonance imaging (MRI). One particular gel recommended by the ASTM standard (F218209) is the polyacrylic acid (PAA) phantom. In this work, PAA mixtures were characterized by measuring viscosity (as a function of shear rate), electrical conductivity, thermal conductivity, and elastic and viscous moduli (as a function of frequency). Experiments compared samples with blend times between 30 seconds and 9 minutes, and measurements were taken over a period of weeks to document the aging process in the phantoms. Results suggest that 3 minutes or more of blending 500 mL quantities causes the sample to transform from a gel (which has a well-defined yield stress) into a viscous liquid. The same transformation was observed in a single sample over a period of two weeks. These results are important because the current ASTM standard does not specify blending time in detail. It is therefore possible that variability in the gel preparation methods could affect the results of experiments to determine the safety of implanted medical devices. These results will help to strengthen the ASTM standard procedure in future revisions.
Michele Mosca, Perimeter Institute
Introduction to Quantum Information Processing
Information processing is a physical process, and thus the powers and limitations of an information processing device depend on the laws of physics. The “classical” framework for physics has long been replaced by quantum physics. Over the past century we have moved from observing quantum phenomena to controlling quantum phenomena. Remarkable progress has been made in recent years.
Very importantly, the quantum features of nature lead to qualitatively different and apparently more powerful models of computation and communication. Quantum computers can efficiently solve problems that were previously believed to be intractable. Quantum information also enables communication and cryptographic tasks that would otherwise not be possible. I will introduce quantum information processing and summarize the state of the art.
Corina Nantais, Queen's University
Measurement of the Radiopurity of Acrylic for the DEAP-3600 Dark Matter Experiment
The DEAP-3600 single-phase liquid argon detector at SNOLAB will increase the sensitivity to spin-independent WIMP-nucleon scatters by two orders of magnitude, allowing for the possibility of dark matter particle detection. The spherical detector will contain 3600 kg of liquid argon in an 85 cm radius acrylic vessel surrounded by 255 photomultiplier tubes (PMTs). After a collision between a WIMP and an Ar-40 nucleus, the scintillation light from the recoiling nucleus will be collected by PMTs. The separation of background events from WIMP events is critical. Detector materials contain levels of uranium and thorium, and these decay chains contain alpha, beta, and gamma decays. Alpha particles near the surface of the acrylic vessel are perhaps the most difficult background. A fraction of the alpha energy, or the recoiling nucleus from the alpha decay, could misreconstruct in the fiducial volume and result in a false candidate dark matter event. The maximum concentrations in the DEAP-3600 acrylic are 0.3 ppt, 1.3 ppt, and 1.1 x 10^-8 ppt for U-238, Th-232, and Pb-210, respectively. The concentrations of U-238, Th-232, and Pb-210 in the bulk acrylic will be measured by vaporizing acrylic, collecting the residue, and counting the contamination in a high-purity germanium well detector.
Miok Park, University of Waterloo
Deformations of Lifshitz Holography in Higher Dimensions
(n+1)-dimensional Lifshitz spacetime is deformed by logarithmic expansions in the way to admit a marginally relevant mode in which z is restricted by n=z+1. According to the holographic principle, the deformed spacetime is assumed to be dual for quantum critical theories, and then thermodynamics of generic black holes in the bulk describe the field theory with a dynamically generated momentum scale $Lambda$. This is a basically UV-expanded theory considered in higher dimensions of the Lifshitz holography from the previous works. By finding the proper counterterms, the renormalized action is obtained and by performing the numerical works, the free energy and energy density is expressed in terms of $T/Lambda^2$.
Cathryn Parsons, Acadia University
MnSi Epitaxial Thin Films: Structure and Magnetic Properties
Epitaxial MnSi grown on Si (111) offers new opportunities in the development of spin-dependent transport in helical magnets. Helical magnets are a class of noncollinear structures that have shown promise as a material for spin-dependent electron transport studies.The helical magnets are of particular interest in spintronics because in these magnets the electron spins spiral about a particular crystallographic direction, this property can allow for control over electron spin. Many interesting magnetic properties can be studied with the combination of thin-film heterostructures and helical magnets. Through use of x-ray diffraction, SQUID magnetometry and transmission electron microscopy, we have observed the structural and magnetic properties of crystalline MnSi thin-films to determine the effects of strain on the magnetic properties. As a result, we have found that epitaxially induced tensile strain results in an increase in the unit-cell volume, and that the atypical strain relaxation behaviour is correlated with a magnetic response.The talk will give a brief outline of the theory/techniques used, and the results gathered.
Aleksandra Petrova, Kasan (Volga Region) Federal University
Quantum Vacuum Polarization Effects and the Estimation of the Stabel Vacuum Lifetime in the Field of a Superheavy Necleus
The vacuum polarization effects in superstrong Coulomb and laser fields are considered from the point of view of the generalized quantum dynamics formalism. The vacuum decay time in superstrong electromagnetic field is discussed.
Adriana Predoi-Cross, University of Lethbridge
Progress and Challenges for Canadian Women Physicists
In recent years there has been an increase in the number of women in all academic levels in physical and applied sciences in Canada. Despite the modern feminist movement the number of women in physics continues to be less than the number of men, particularly in higher and leadership positions. As there is no rational reason for women to trail men in achieving new scientific discoveries or excel in academic teaching, the cause of this is attributed to existing gender biases in the perception and practice of science. Thus increasing the number of women in physics as well as emphasising their relevance in physics has emerged as a women’s issue. At the national level, the overall climate for women physicists both in academia and industry has improved significantly over the past decade. Balancing a family and career is not easy, and in particular not for academics or physicists. Even though a number of universities have programs, leaves, and flexibility of teaching duties in place for parents, balancing the demands of a university or governmental/industrial research position and a newborn child can be very challenging. This talk will cover a variety of topics from the importance of starting outreach activities at a young age, to national physics associations’ role in addressing women’s issues and the challenges facing spouses who are both pursuing academic careers.
Vanessa Punal, Oakland University
A Perturbation Solution Of The Mechanical Bidomain Model
This research focuses on finding analytical solutions to the mechanical bidomain model of cardiac tissue. In particular, a perturbation expansion is used to analyze the equations, with the perturbation parameter being inversely proportional to the spring constant coupling the intracellular and extracellular spaces. The results indicate that the intracellular and extracellular pressures are not equal, and that the two spaces move relative to each other. This calculation is complicated enough to illustrate the implications of the mechanical bidomain model, but is nevertheless simple enough to solve analytically. The zeroth-order of the perturbation expansion reveals that the intracellular and extracellular displacements are equal, thus making it unnecessary to account for either space on an individual basis. Yet, in the first-order of the expansion we see a shift and the intracellular and extracellular displacements are unequal. One application of the calculation is to the mechanical behavior of active cardiac tissue surrounding an ischemic region. Also, a hypothesis for the physical meaning of the pressure inequality is if this inequality is held for an extended period of time it may cause fluid to flow across the cell membrane and in the tissue.
Shohreh Rahmati, University of Lethbridge
Vacuum Polarization in Quantum Gravity
The objective of our project is to study Hawking radiation which is produced from vacuum polarization in the vicinity of the horizon.
Sophie Rochette, University of Sherbrooke
Introduction to Spin Control in Lateral Quantum Dots and Micro-Magnets Characterization
Development of quantum computing promises, among other things, improvement of scientific computation performance. Indeed, a computer exploiting the proprieties of quantum mechanics would allow for computation power exponentially greater than a classic computer.We develop double lateral quantum dots with micro-magnets to control spin orientation of electrostatically confined electrons. In this talk, an introduction to the mechanisms used in the spin control will be given. Then, methods used to characterize the micro-magnets will be described. Finally, we will present the results obtained with Hall effect devices for the micro-magnets.
Hoimonti Rozario, University of Lethbridge
Spectroscopic Study of Atmospheric Trace Gases
Molecular spectroscopy offers the tools and instrumentation needed to unveil the structure and characteristics of molecules that are found within planetary atmospheres. In order to do this we examine the frequencies of light that these molecules either absorb or emit. It is the fine structure of these absorption or emission features that give us information about their physical state.. In our lab we use a near-infrared source to probe various molecules and examine absorption features and their dependency on both temperature and pressure. In this study we plan to retrieve the N2-broadened widths, pressure-induces N2-shifts and N2-broadened line mixing coefficients for twenty two transitions in the P branch of the ν1+ν3 band of acetylene mixed with nitrogen. The gas mixture has been selected to be 10% acetylene and 90 % nitrogen. We will record spectra using a 3 channel tuneable diode laser spectrometer. The system contains a temperature controlled single pass absorption gas cell of fixed length, a room temperature cell filled with pure acetylene gas used to create a reference spectra and a third background cell. The system is controlled by LabVIEW software which will be discussed.Simulations have been performed on the v1+v3 band using data obtained from the HITRAN database and will be presented. . From the simulations we determined that we can measure twenty two lines in the P-branch of this band. These lines are all within the interval of P(1)-P(31). For each line we will record spectra at pressures of 100, 250, 400 and 500 torr and for each pressure we plan on measuring 7 different temperatures ranging from -60 to 60C. From these recorded spectra we hope to obtain line parameters using a nonlinear least squares fitting routine. The routine will allow for use of several different line shape models. This study will be the first one over a range of temperatures.
Marisa Smith, Mount Allison University
Using Antimatter to Aid in the Design of Safer more Efficient Nuclear Power Plants
We are doing research on the chemical reaction of the hydrogen atom with water under sub- and supercritical conditions. Supercritical water is water above the critical point (373.9 C and 220.6 bar). This reaction is one of the most important reactions in the next generation of nuclear reactors called Gen IV, where supercritical water will be used as a coolant. We have been studying this reaction by the SR experimental technique. SR is the only technique that is able to work under these extreme conditions to provide kinetics data and it can be a billion times more sensitive than other techniques. TRIUMF, the particle accelerator in Vancouver is the facility that we used to collect data.
Maryam Taheri, Brock University
Impact of Gd-site Doping on Magnetic, Transport and Specific Heat Behavior of Multi-Ferroic Gd2CuO4
The magnetic properties of ceramic samples of Gd1.98R0.02CuO4 R= Ca Sr Th were studied and compared with Gd2CuO4. The results showed weak ferromagnetic ordering in all samples. We observed two magnetic ordering temperatures in the heat capacity measurement a sharp peak at TN(Gd) 6.5 K that can be attributed to the Neel temperature of Gd3+ ions and the second transition temperature at about 20 K that suggested to the magnetic interactions of Gd-Cu. The third anomaly was seen at TN(Cu)=280 K in susceptibility measurements. Investigations indicated that 0.02% mole substitution for Gd was not much effective on the transition temperature of compounds although we bserved significant change in the magnitude of heat Capacity susceptibility and magnetization of samples as well as their conductivities.
Francesca Vidotto, Centre de Physique Thorique, Marseille
What's the Entropy of Gravity?
I present a proposal, originally motivated by a result in graph theory: the entropy function of a density matrix naturally associated to a simple undirected graph, is maximized, among all graphs with a fixed number of links and nodes, by regular graphs.I recover this result starting from the Hamiltonian operator of a non-relativistic quantum particle interacting with the loop-quantized gravitational field and setting elementary area and volume eigenvalues to a fixed value. This operator provides a spectral characterization of the physical geometry, and can be interpreted as a state describing the spectral information about the geometry available when geometry is measured by its physical interactionwith matter. It is then tempting to interpret the associated entropy function as a genuine physical entropy: I discuss the difficulties of this interpretation and I present a possible viable definition of quantum-gravitational entropy.
Di Wan, University of Calgary
Scattering Kernel for Aperture Modulated Total Body Irradiation
The goal of Total Body Irradiation (TBI) is to deliver a uniform dose of radiation to the entire body, to destroy cancerous cells. Since the human body is not uniform in either density or thickness, it is difficult to deliver a uniform dose. A novel, Aperture Modulated, Total Body Irradiation (AMTBI) technique was introduced by researchers at the Tom Baker Cancer Centre to address this problem. The AMTBI technique reduces the dose deviation along the midline in the longitudinal direction to less than 5%, as compared to 15% with conventional TBI. This improvement in dose homogeneity is achieved by dynamically changing the apertures of the Multi-Leaf Collimator (MLC) according to the radiative area’s radiological depth. The dose at a point in a medium can be analyzed in two parts: primary and scattered components. Up to now, the calculation did not include the scattered components. By analyzing experimental data, I determined scattering kernels to optimize the field sizes using MLC. This will allow us to deliver a more homogenous dose at the midline.
Xiaoya Judy Wang, McGill University
Theory of Heavy-Hole Spin Echoes
Heavy-hole spin states have been proposed as a robust qubit candidate. Nevertheless, the coupling of the hole spins to nuclei in the surrounding medium likely limits hole-spin coherence and has, until very recently, been overlooked. We describe the spin decoherence of a heavy-hole in a semiconductor quantum dot, subject to spin echo pulses. We do so both analytically and numerically for an experimentally realistic number (10^4) of nuclear spins. Including the (previously neglected) nuclear Zeeman term in the Hamiltonian, we observe novel effects uniquely characterizing the decoherence mechanisms under study. In particular, we find a nontrivial dependence of the decay on the applied magnetic field, as well as novel predictions for motional narrowing and envelope modulation, which could significantly extend the hole-spin memory time in near-future experiments.
Lucy Liuxuan Zhang, University of Toronto
Mathematics and Topological Quantum Computation