Events List for the Academic Year
Event Time:
Thursday, September 26, 2019 | 4:00 pm - 5:00 pm
Event Location:
Hennings 201
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2019-09-26T16:00:00
2019-09-26T17:00:00
Trinity – Klaus Fuchs and the Security Services, from A bomb to Z pinch
Event Information:
Trinity was the codename for the test explosion of the atomic bomb in New Mexico on 16 July 1945. Frank Close tells the story of: the bomb's metaphorical father, Rudolf Peierls (Prof. Close's one time mentor in Oxford); his intellectual son, the atomic spy Klaus Fuchs; and the ghosts of the security services in Britain, the USA and USSR. Frank will reveal new insights from MI5 files in the British National Archives, and documents of the FBI and KGB. He has also overthrown a misconception lasting 60 years that J Edgar Hoover was central to Fuchs' exposure: the real hero was probably Britain's GCHQ. Documents that Fuchs sent to the USSR about the atomic and hydrogen bombs 70 years ago are still classified secret in the UK but access to these has become possible (in one case from Russia itself!), revealing new insights into Fermi's ideas about the hydrogen bomb and supporting a claim that Fuchs was the "grandfather" of the H bomb in the USA, UK and USSR.
Event Location:
Hennings 201
Event Time:
Thursday, September 26, 2019 | 2:30 pm - 4:30 pm
Event Location:
Room 318 Hennings, 6224 Agricultural Road
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2019-09-26T14:30:00
2019-09-26T16:30:00
Final PhD Oral Examination (Thesis Title: “Dawning of Nuclear Magicity in N=32 Seen Through Precision Mass Spectrometry”)
Event Information:
Abstract:
In the early days of nuclear science, physicists were astounded that specific "magic" combinations of neutrons or protons within nuclei seemed to bind together more tightly than other combinations. This phenomenon was related to the formation of shell structures in nuclei. More recently, nuclear shells were observed to emerge or vanish as we inspect nuclei further from stability. The structural evolution of these changing shells has been the object of intense experimental investigation, and their behavior has become a standard ruler to benchmark theoretical predictions.
In this work, we investigated the emergence of shell effects in systems with 32 neutrons (N=32) using mass spectrometry techniques. Evidence for "magicity" was observed in potassium (with 19 protons, or Z=19), calcium (Z=20) and scandium (Z=21), but not in vanadium (Z=23) and heavier elements. In between, the picture at titanium (Z=22) was unclear.
We produced neutron-rich isotopes of titanium and vanadium through nuclear reactions at the ISAC facility and measured their atomic masses at the TITAN facility, in the TRIUMF Laboratory in Vancouver. These measurements were performed with the newly commissioned Multiple-Reflection Time-of-Flight Mass Spectrometer at TITAN facility and were substantiated by independent measurements from the Penning trap mass spectrometer. The atomic masses of 52Ti to 55Ti and 52V to 55V isotopes were measured with high precision, right at the expected emergence of N=32 shell effects. Our results conclusively establish the existence of weak shell effects in titanium and confirm their absence in vanadium, narrowing down the precise onset of this shell closure.
Calculations of the N=32 nuclear shell are within reach of the so-called "ab initio" theories. In these, complex atomic nuclei are described theoretically from fundamental principles, by applying principles of Quantum Chromodynamics to many-body quantum methods. Our data were compared with a few state-of-the-art ab initio calculations which, despite very successfully describing the N=32 shell effects in Ca and Sc isotopes, overpredict its strength in Ti and erroneously assign V as its point of appearance. We hope the deficiencies revealed by our work will guide the development of the next generation of ab initio theories.
Event Location:
Room 318 Hennings, 6224 Agricultural Road
Event Time:
Thursday, September 26, 2019 | 2:00 pm - 3:00 pm
Event Location:
BRIM 311
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2019-09-26T14:00:00
2019-09-26T15:00:00
CM Seminar - High field superconducting magnet science for particle and condensed matter physics
Event Information:
Abstract : Magnets are unarguably the "killer app" of superconductivity, with medical imaging magnets comprising an annual $2 billion market that consumes about 1000 tons of superconductor per year, and magnets for large science projects contributing a similar share. Yet, no magnet is ever better than the conductors from which it is wound, making the frontier of magnet technology inseparably connected to limits of conductor manufacturing and basic materials science. The Applied Superconductivity Center (ASC) has played a central role in the advance of conductor and magnet technology for particle physics for over 4 decades, and ASC continues this role in partnership with the US Department of Energy Office of High Energy Physics and the US Magnet Development Program. This presentation will highlight the present status of conductor and magnet technology for the High-Luminosity upgrade of the Large Hadron Collider at CERN, as well as prospects for 2050-era colliders at 100 TeV energy. After moving to the National High Magnetic Field Laboratory (NHMFL) in 2006, the ASC worked in earnest on the challenges of very high field magnets made from high-temperature superconductors (HTS), now being implemented as the world's first all-superconducting user magnet at 32 T. Conductor technology now provides multiple options for magnet technology in the 40 T to 60 T range for condensed matter physics and other user communities, as well as nuclear magnetic resonance opportunities above 30 T and 1.3 GHz. This presentation will also describe ongoing work toward these goals from the point of view of limitations at the conductor level and innovations in magnet technology to overcome them. NHMFL has over 2,000 users annually, most of which are in the condensed matter, chemistry, and biology communities, and for these stakeholders the ability to "sit" at very high magnetic field measurements for long periods of time will transform present experiments. The presentation will highlight some of the NHMFL's science drivers and recent headline results.
Biosketch: Lance Cooley is a professor in the Department of Mechanical Engineering at Florida State University, in addition to his MagLab roles as director of the Applied Superconductivity Center (ASC) and an associate lab director. Cooley began his career in superconducting materials in 1986 at the University of Wisconsin – Madison, in the Applied Superconductivity Center where he explored the ultimate limits of electric current in superconducting wires used for magnets. He earned a National Research Council Postdoctoral Fellowship at the National Institute of Standards and Technology in Boulder, Colorado, and later returned to Madison, Wisconsin, as a member of the research faculty to further investigate limits of superconductors. The discovery of superconductivity in magnesium diboride in 2001 prompted Cooley to move to Brookhaven National Laboratory, where he eventually became head of the Superconducting Materials Group. He moved to Fermilab in 2007 to lead the SRF Materials Group, and later the Superconducting Materials Department. During this time, he coordinated external programs at multiple universities, laboratories and industry to improve performance of superconducting radio-frequency cavities and superconducting wires. This led to specifications and international standards related to niobium commerce, for which he received the International Electrotechnical Commission 1906 Award. He joined Florida State University and MagLab in 2017. He is also the manager of conductor acquisition for the Large Hadron Collider High-Luminosity Accelerator Upgrade Project as well as the head of Conductor Procurement and R&D for the National Magnet Development Program, both in the U.S. Department of Energy Office of High-Energy Physics.
Event Location:
BRIM 311
Event Time:
Thursday, September 26, 2019 | 9:00 am - 11:00 am
Event Location:
Room 203 of the Graduate Student Centre (6371 Crescent Road)
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2019-09-26T09:00:00
2019-09-26T11:00:00
Final PhD Oral Examination (Thesis Title: “Designing Quantum Phases in Monolayer Graphene”)
Event Information:
Abstract:
The physics of quantum materials is at the heart of current condensed matter research. The interactions in these materials between electrons themselves, with other excitations, or external fields can lead to a number of macroscopic quantum phases like superconductivity, the quantum Hall effect, or density wave orders. But the experimental study of these materials is often hindered by complicated structural and chemical properties as well as by the involvement of toxic elements. Graphene, on the other hand, is a purely two-dimensional material consisting of a simple honeycomb lattice of carbon atoms. Since it was discovered experimentally, graphene has become one of the most widely studied materials in a range of research fields and remains one of the most active areas of research today. However, even though graphene has proven to be a promising platform to study a plethora of phenomena, the material itself does not exhibit the effects of correlated electron physics.
In this thesis, we show two examples of how epitaxially grown large-scale graphene can be exploited as a platform to design quantum phases through interaction with a substrate and intercalation of atoms. Graphene under particular strain patterns exhibits pseudomagnetic fields. This means the Dirac electrons in the material behave as if they were under the influence of a magnetic field, even though no external field is applied. We are able to create large homogeneous pseudomagnetic fields using shallow nanoprisms in the substrate, which allows us to study the strain-induced quantum Hall effect in a momentum-resolved fashion using angle-resolved photoemission spectroscopy (ARPES). In the second part, we show how the intercalation of gadolinium can be used to couple flat bands in graphene to ordering phenomena in gadolinium. Flat bands near the Fermi level are theorised to enhance electronic correlations, and in combination with novel ordering phenomena, play a key role in many quantum material families. Our ARPES and resonant energy-integrated X-ray scattering (REXS) measurements reveal a complex interplay between different quantum phases in the material, including pseudogaps and evidence for a density wave order.
Event Location:
Room 203 of the Graduate Student Centre (6371 Crescent Road)
Event Time:
Monday, September 23, 2019 | 3:00 pm - 4:00 pm
Event Location:
Hennings 318
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2019-09-23T15:00:00
2019-09-23T16:00:00
Planets Big and Small
Event Information:
From gas-poor Earths to gas-rich Jupiters, planets come in a variety of sizes. I will describe the physics behind the diversity of exoplanets - how the core and gas assembly processes give rise to the observed distribution of radii and orbital periods. Basic astrophysical considerations of gas dynamical friction, gravitational scattering, collisional mergers, and gas accretion by cooling inform us that planets smaller than Neptune likely emerged in situ, in the late stages of disk evolution. Larger planets on the other hand must have nucleated from massive cores that assemble in the early stages of disk evolution. Observations report a comparable population of sub-Saturns as Jupiters, contrary to the expectation of the model of runaway gas accretion. I will discuss the importance of hydrodynamic considerations in halting the runaway.
Finally, I will show how the theory of star-disk-planet interaction can describe the observed planet occurrence rate as it varies across orbital periods, planet radii, and stellar metallicities.
Event Location:
Hennings 318
Event Time:
Monday, September 23, 2019 | 2:00 pm - 3:00 pm
Event Location:
TRIUMF Auditorium
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2019-09-23T14:00:00
2019-09-23T15:00:00
Half Life – the divided life of Bruno Pontecorvo, physicist and spy
Event Location:
TRIUMF Auditorium
Event Time:
Thursday, September 19, 2019 | 4:00 pm - 5:00 pm
Event Location:
Hennings 201
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2019-09-19T16:00:00
2019-09-19T17:00:00
Ensnared Between Hitler and Stalin: Refugee Physicists in the Soviet Union
Event Information:
David Zimmerman is Professor of History at the University of Victoria, British Columbia, Canada. He is the author of "Britain's Shield: Radar and the Defeat of the Luftwaffe"; "Top Secret Exchange: The Tizard Mission and the Scientific War"; "The Great Naval Battle of Ottawa"; "Coastal Fort: A History of Fort Sullivan, Maine"; and "Maritime Command Pacific: The Royal Canadian Navy in the Pacific during the Early Cold War". He has published over twenty articles, on various aspect of naval and military history, the early history of the Society for the Protection of Science and Learning; as well as an article on Canada and the academic refugee crisis. In 2017 he published in the journal War and History "A more creditable way: The Discovery of Active Sonar, the Langevin-Chilowsky Patent Dispute and the Royal Commission on Awards to Inventors". This December his article, "Competitive Cooperation: The Society for the Protection of Science and Learning, the American Emergency Committee, and the Placement of Refugee Scholars in North America," was published in Yad VaShem Studies. He is currently writing a book, "Ensnared Between Hitler and Stalin: Academic Refugees in the USSR." He is President of the Victoria Holocaust Education and Remembrance Society.
Event Location:
Hennings 201
Event Time:
Thursday, September 19, 2019 | 2:00 pm - 3:00 pm
Event Location:
TRIUMF Auditorium
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2019-09-19T14:00:00
2019-09-19T15:00:00
Challenges in gravitational wave astronomy
Event Information:
Advanced LIGO and Advanced Virgo are currently in the middle of their third observing run, and releasing open public event alerts for the first time. The LIGO-Virgo collaboration has issued 28 un-retracted candidate event alerts as of September 11th, 2019, potentially adding dozens more known compact binary object mergers to the eleven confident detections from the first two Advanced-era observing runs. I'll give an overview of the process of detecting, characterizing, and assessing the significance of gravitational wave signals registered in Advanced LIGO data. I’ll review novel results from LIGO-Virgo to date, and the challenges of extracting interesting new physics from noisy detector data. Finally, I'll summarize the roadmap to future gravitational wave detectors on Earth and in space.
Event Location:
TRIUMF Auditorium
Event Time:
Thursday, September 19, 2019 | 2:00 pm - 3:00 pm
Event Location:
BRIM 311
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2019-09-19T14:00:00
2019-09-19T15:00:00
CM Seminar - Band Structure Movies of Electrical Surface Currents
Event Information:
Abstract:
Time-resolved photoelectron spectroscopy combines femtosecond pump-probe techniques with angle-resolved photoelectron spectroscopy (ARPES). I will show how this method can be used to perform measurements of electron transport at surfaces and interfaces in a contact-free fashion and with femtosecond time-resolution [1-3]. As the main example, I will discuss Dirac surface states of topological insulators. We induce electrical currents in these states with strong THz transients and directly access their dynamics in momentum space with subcycle time resolution. As a result of spin-momentum locking, the accelerated spin-polarized electrons reach ballistic mean free paths of several hundreds of nanometers. Our results show that topological insulators are promising materials for future lightwave-driven electronics operating at THz clock rates [3].
[1] J. Güdde, M. Rohleder, T. Meier, S. W. Koch, and U. Höfer, Science 318, 1287 (2007).
[2] K. Kuroda, J. Reimann, J. Güdde, and U. Höfer, Phys. Rev. Lett. 116, 076801 (2016).
[3] J. Reimann, S. Schlauderer, C. P. Schmid, F. Langer, S. Baierl, K. A. Kokh, O. E. Tereshchenko, A. Kimura, C. Lange, J. Güdde, U. Höfer, and R. Huber, Nature 562, 396 (2018).
Biography:
Ulrich Höfer received a doctoral degree in physics in 1989 from the Technical University of Munich, Germany. After spending two years as a visiting scientist at the IBM Thomas J. Watson Research Center in Yorktown Heights, New York, he joined the Max-Planck-Institute for Quantum Optics in Garching, Germany. In 1999 he became a full professor for experimental physics at the Philipps University in Marburg. His main research interests are laser spectroscopy of surfaces and interfaces, coherence and ultrafast phenomena at surfaces, and the dynamics of elementary adsorbate reactions. Since 2013 he is the spokesman of a collaborative research center on the structure and dynamics of internal interfaces.
Event Location:
BRIM 311
Event Time:
Thursday, September 19, 2019 | 10:30 am - 12:30 am
Event Location:
Room 158, Irving K. Barber, 1961 East Mall
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2019-09-19T10:30:00
2019-09-19T00:30:00
Final PhD Oral Examination (Thesis Title: “Dissertation Title: Exploring the Tumour Microenvironment with Non-Invasive Magnetic Resonance Imaging Techniques”)
Event Information:
Abstract:
This thesis comprises development and application of several MRI techniques to improve our understanding of tumour growth, drug distribution, and drug effect using pre-clinical tumour models in mice. In the first part of the thesis, a novel high molecular weight contrast agent, HPG-GdF is introduced. This molecule is a hyperbranched polyglycerol labeled with an MRI contrast agent (Gd-DOTA) as well as a fluorescent tag. After injecting the agent into mice within an MRI scanner, contrast-agent kinetics were quantified using a two-parameter linear model and validated with quantitative immunohistochemistry via direct fluorescence imaging of HPG-GdF.
HPG-GdF was used to assess whether vascular function plays a role in how a chemotherapy (Herceptin) distributes within a tumour. Tumour vessel permeability and fractional plasma volume were quantified using the HPG-GdF and no relationship was found between vascular function and presence of drug. HPG-GdF was then applied to show that Avastin (an antiangiogenic agent) decreased vessel permeability in tumours. Using histological methods, a dramatic reduction in hypoxia (oxygen deficiency in tissues) was observed in treated tumours. Unfortunately, existing MRI methods to evaluate oxygenation were time-intensive and lacked sensitivity. In the second part of this thesis, we introduce, develop, validate, and apply a new method to assess tumour oxygenation using MRI.
Oxygen (O2) is a paramagnetic molecule that shortens the longitudinal relaxation time (T1) of protons in MRI. This subtle effect has been widely reported in the literature but its applications in cancer have been limited. Our technique - dynamic oxygen-enhanced MRI (dOE-MRI) - uses T1 weighted signal intensity images acquired during a cycling gas challenge (air or oxygen) and independent component analysis (ICA). Hypoxia staining with pimonidazole correlated strongly with dOE-MRI values in a murine tumour model (SCCVII) and only weakly in a colorectal xenograft model (HCT-116). Finally, we provide compelling evidence that treatment with Avastin improves tumour oxygenation in subcutaneous tumours. With dOE-MRI the sensitivity and speed of existing techniques was greatly improved. Since our technique requires no injectable contrast agent, special sequences or hardware, we anticipate that this technique can be quickly translated into the clinic.
Event Location:
Room 158, Irving K. Barber, 1961 East Mall
Event Time:
Wednesday, September 18, 2019 | 9:00 am - 11:00 am
Event Location:
Room 200, Graduate Student Centre (6371 Crescent Road)
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2019-09-18T09:00:00
2019-09-18T11:00:00
Final PhD Oral Examination (Thesis Title: “High Resolution Two-Photon Spectroscopy of 129Xe for Precision Optical Magnetometry”)
Event Information:
Abstract:
This dissertation presents high precision two-photon xenon spectroscopy of the 5 p5 (2 P3/2 )6 p 2 [3/2]2 ← 5 p6 (1 S0 ) transition. Specific attention is paid to the F = 3/2 hyperfine level of 129Xe, motivated by the new experiment at TRIUMF to measure the electric dipole moment of the neutron. A non-zero value of the nEDM would partially confirm the existence of the baryon asymmetry in the universe as predicted by theories beyond the standard model. To achieve this measurement, 129Xe is proposed for use in a cohabiting 199Hg/129Xe dual species optical comagnetometer. To date no laser system has existed to probe the xenon 5p5(2P3/2)6p 2[3/2]2 ← 5p6 (1S0) transition required for this measurement.
We developed a novel continuous-wave 252.4 nm ultra-violet (UV) laser system with the power and precision to selectively probe the hyperfine levels of 129Xe. Using this laser system, we observed the first high resolution two-photon transition spectrum of xenon, which is comprised of ten tran- sition peaks across the six most abundant isotopes, including the hyperfine levels of the 129Xe and 131Xe. Detailed analysis of this spectrum revealed the hyperfine constants of the 5p5(2P3/2)6p2[3/2]2 excited state and other constants relating to the isotope shift. Furthermore, utilizing this laser sys- tem, we describe initial observations into the pressure dependencies of the spectral lineshape from 15–980 mTorr. The 129Xe pressure in the nEDM experiment is limited to 3 mTorr, making it es- sential to characterize the xenon signal at low pressures to maximize comagnetometer sensitivity. Intriguingly, our results suggest that 129Xe qualitatively exhibits nonlinear pressure broadening at ultra-low pressures - a phenomenon reminiscent of some other gases. However, further investigation is required to fully conclude the pressure broadening effects in 129Xe.
Overall, these results define the expected signal size and relative transition frequency to the F = 3/2 hyperfine level of 129Xe for precision laser tuning. Collectively, this work contributes to optical magnetometry in nEDM experiments, as well as to precision spectroscopy and theories of atom-atom interactions.
Event Location:
Room 200, Graduate Student Centre (6371 Crescent Road)
Event Time:
Monday, September 16, 2019 | 3:00 pm - 4:00 pm
Event Location:
Hennings 318
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2019-09-16T15:00:00
2019-09-16T16:00:00
Exploring 10000 of the Nearest Star Systems
Event Information:
The nearest stars and their companions provide the fundamental framework upon which all of stellar astronomy is based, for individual stars, stellar multiples, and entire stellar populations. We live in exciting times, as our map of the Sun's neighbors becomes enriched with details of other solar systems that will ultimately play key roles in our search for life elsewhere.
The RECONS (REsearch Consortium On Nearby Stars, www.recons.org) team endeavors to understand the nature of the Sun's nearest stellar neighbors, both individually and as a population. We reveal "missing" members of the (very) local neighborhood, focusing on the 10 parsec sample, a distance horizon that corresponds to 32.6 light years. To date, we have found 44 new star systems in this sphere, accounting for one of every seven systems in the sample. In the process, we have learned that 75% of all stars are the Sun's smaller, cooler cousins, known as red dwarfs of spectral type M, which dominate our Milky Way Galaxy.
As leaders of the SMARTS Consortium, RECONS uses telescopes at the Cerro Tololo Inter-American Observatory located in the foothills of the Chilean Andes for two long-duration surveys of K and M dwarfs. We are revealing key astrophysical insights about the nearest stars, including the orbital architectures of multiple systems, the long-term variability of red dwarfs, and the identification of young stars near the Sun. One ultimate goal is to understand how the populations of companions to stars - stellar, brown dwarf, and planetary - relate to one another. In particular, while many planets have yet to be detected, we now know that the solar neighborhood is dominated by small stars that are potentially orbited by many small, as yet unseen, planets.
Event Location:
Hennings 318
Event Time:
Friday, September 13, 2019 | 11:00 am - 12:00 pm
Event Location:
BRIM 311
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2019-09-13T11:00:00
2019-09-13T12:00:00
Seminar: Generative training of quantum Boltzmann machines with hidden units
Event Information:
We provide the first method for fully quantum generative training of quantum Boltzmann machines with both visible and hidden units while using quantum relative entropy as an objective. This is significant because prior methods were not able to do so due to mathematical challenges posed by the gradient evaluation. We present two novel methods for solving this problem. The first proposal addresses it, for a class of restricted quantum Boltzmann machines with mutually commuting Hamiltonians on the hidden units, by using a variational upper bound on the quantum relative entropy. The second one uses high-order divided difference methods and linear-combinations of unitaries to approximate the exact gradient of the relative entropy for a generic quantum Boltzmann machine. Both methods are efficient under the assumption that Gibbs state preparation is efficient and that the Hamiltonian are given by a sparse row-computable matrix.
Event Location:
BRIM 311
Event Time:
Thursday, September 12, 2019 | 4:00 pm - 5:00 pm
Event Location:
Hennings 201
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2019-09-12T16:00:00
2019-09-12T17:00:00
Understanding Complex Quantum Dynamics Using Machine Learning
Event Information:
In recent years, quantum experiments have become increasingly complicated, with modern experiments pushing the limits of even our best supercomputers to simulate. This increased complexity has made quantum devices challenging to model, which in turn makes them both difficult to control in quantum technologies and also exceedingly difficult to understand. In this talk, I will show how ideas from machine learning and statistical inference can be used to probe complex quantum systems. In particular, we will show how these methods can allow us to identify common pathologies in devices, as well as infer Hamiltonian dynamics for quantum systems. This latter ability has led to a world record for room-temperature magnetometry using Nitrogen vacancy centers, which was achieved not by engineering a new device but rather through the use of machine learning to extract a weak signal from noisy data. These results illustrate the growing importance of machine learning techniques to quantum science and technology and suggest a new methodology for analyzing as well as controlling physical systems.
Event Location:
Hennings 201
Event Time:
Thursday, September 12, 2019 | 2:00 pm - 3:00 pm
Event Location:
Brim 311
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2019-09-12T14:00:00
2019-09-12T15:00:00
CM Seminar - Hydrodynamic transport in Luttinger semi-metals
Event Information:
Abstract: In the hydrodynamic regime it is possible to investigate the universal collision-dominated dynamics of the isolated electron fluid, while the couplings to the lattice and to impurities becomes secondary. An important transport property is the shear viscosity which describes whether the electron fluid behaves laminar or turbulent. The ratio shear viscosity over entropy is bounded from below and is an indicator for how strongly the system is interacting [Kovtun]. We determine the shear viscosity in Luttinger metals which are semimetals with a quadratic energy band touching point. Especially we focused on the determination of the shear viscosity in the Luttinger-Abrikosov-Beneslavskii phase [Moon]. This phase occurs upon adding the long-range Coulomb interaction to the system and it is an interacting, scale invariant, and non-Fermi-liquid phase. Upon combining the Boltzmann formalism with an RG analysis, we find that the ratio viscosity over entropy comes very close to the lower bound which makes the Luttinger metals a nearly perfect electron fluid.
Biosketch: Julia Link did her Bachelor and Master studies in physics at the University of Heidelberg in Germany from 2007 to 2012. For her doctoral studies, she changed to the Karlsuhe Institute of Technology where she finished her PhD under the supervision of Jörg Schmalian in December 2017. During her PhD she studied the effects of the Coulomb interaction on transport properties of isotropic and anisotropic Dirac systems in the optical and the hydrodynamic regime. Since September 2018 she is a Postdoctoral researcher at SFU in the group of Igor Herbut where she studies the hydrodynamic transport of Luttinger semimetals.
Event Location:
Brim 311
Event Time:
Thursday, September 12, 2019 | 2:00 pm - 3:00 pm
Event Location:
TRIUMF Auditorium
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2019-09-12T14:00:00
2019-09-12T15:00:00
Searching for Muon to Electron Conversion in a Muonic Atom - Quest for new physics
Event Information:
Muon to electron conversion is a process which violates the conservation of charged lepton flavor. It is forbidden in the Standard Model, but new physics beyond the SM predict its sizable rate. New experiments under preparation in Japan and the US will start soon in a few years, aiming at improvement of four orders of magnitude, with new innovative muon sources. This talk will discuss Its physics motivation, and an outlook on the experiments.
Special seminar in honour of Toshio Numao.
Event Location:
TRIUMF Auditorium
Event Time:
Tuesday, September 10, 2019 | 2:00 pm - 3:00 pm
Event Location:
TRIUMF Auditorium
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2019-09-10T14:00:00
2019-09-10T15:00:01
Probing the Higgs – China's Initiative on Future Colliders
Event Information:
We found a Higgs boson and are learning more its properties with collision data from the Large Hadron Collider (LHC) and its future upgrade HL-LHC. But to unveil the fundamental nature of this particle and to explore potential new physics, we would need high energy electron-positron colliders with high luminosity. In this talk, I will introduce such an initiative from China, the Circular Electron Positron Collider (CEPC). I will discuss its science case, the conceptual design, and the status and prospects of the project.
Event Location:
TRIUMF Auditorium
Event Time:
Monday, September 9, 2019 | 3:00 pm - 4:00 pm
Event Location:
Hennings 318
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2019-09-09T15:00:00
2019-09-09T16:00:00
Hot Atmospheres and Black Hole Activity in Massive Galaxies
Event Information:
Most galaxies comparable to or larger than the mass of the Milky Way host hot, X-ray emitting atmospheres, and many such galaxies are radio sources. Hot atmospheres and radio jets and lobes are the ingredients of radio-mechanical active galactic nucleus (AGN) feedback. While a consensus has emerged that such feedback suppresses cooling of hot cluster atmospheres, less attention has been paid to massive galaxies where similar mechanisms are at play. I will review the results of X-ray and multi-wavelength observations of galactic atmospheres, including their chemical composition, dynamics, development of thermal instabilities, AGN heating and the correlations of their properties with the central supermassive black holes.
Event Location:
Hennings 318
Event Time:
Friday, September 6, 2019 | 9:30 am - 11:30 am
Event Location:
Room 309, Hennings Bldg
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2019-09-06T09:30:00
2019-09-06T11:30:00
Final PhD Oral Examination (Thesis Title: “Measurement of the Arterial Input Function from Radial MR Projections”)
Event Information:
Abstract:
DCE-MRI provides a non-invasive method to probe the health status of tissue and help identify diseases, such as cancer. Biologically relevant information is extracted by fitting the data to a pharmacokinetic model. The accuracy of the fit parameters is highly sensitive to the quality of the input curves: the contrast-time curve in the tissue of interest, and the arterial input function, which characterizes the contrast kinetics of a blood vessel feeding the tissue. The AIF is difficult to measure in pre-clinical studies in mice due to their small body size and limited number of vessels of sufficient size. As a result, several groups use a population averaged AIF from the literature. This curve does not account for inter or intra individual differences, and is specific to a particular injection protocol.
This thesis presents a projection-based measurement that measures the AIF from a single trajectory in k-space, which provides a temporal resolution equal to the repetition time (TR). The projection-based AIF allows for acquisition of DCE-MRI data between successive measurements, while maintaining a high temporal resolution of both data sets. A dual-coil experimental platform is set up to acquire a projection-based AIF in the mouse tail, concurrently with DCE-MRI data at a tumour implanted on the hind flank. The results show that an AIF, with a temporal resolution of 100 ms, may be acquired in the mouse tail. Using this curve in the model fit provided K_trans = 0.145 min^-1, and v_e = 0.269. These values are consistent with other studies involving tumours.
Event Location:
Room 309, Hennings Bldg
Event Time:
Thursday, September 5, 2019 | 4:00 pm - 5:00 pm
Event Location:
Hennings 201
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2019-09-05T16:00:00
2019-09-05T17:00:00
Dragonfly: NASA's Rotorcraft Lander mission to Saturn's Moon Titan
Event Information:
NASA recently selected the Dragonfly quadcopter, on which I serve as Deputy Principal Investigator, as the fourth mission in its New Frontiers program of planetary missions. Dragonfly will land on the surface of Saturn's hazy moon Titan to explore prebiotic chemistry, to evaluate its habitability, and look for chemical biosignatures. Titan is one of just 4 planetary bodies that has both a thick atmosphere and a solid surface - Venus, Earth, and Mars are the others. Among these, only Titan and Earth have active hydrological cycles with clouds, rain, and surface lakes and seas, though Titan's contain methane and ethane instead of water. I will discuss the present state of our knowledge about Titan's geology, chemistry, and meteorology, as well as discuss the Dragonfly mission and how it will answer outstanding questions. (1) How far has prebiotic chemistry progressed toward life? (2) What potentially habitable biomes might Titan posess, both with respect to water-based life and methane/ethane-based "life, but not as we know it"? And (3) is there chemical evidence for past or extant life on Titan?
Event Location:
Hennings 201