Events List for the Academic Year
Event Time:
Friday, December 2, 2022 | 1:30 pm - 3:30 pm
Event Location:
Hennings 318
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2022-12-02T13:30:00
2022-12-02T15:30:00
Computational Modeling and Design of Oligomer Selective Vaccine Candidates for Parkinson’s and Alzheimer’s Disease
Event Information:
Protein aggregation-related diseases, in particular neurodegenerative diseases, are characterized by the aberrant perturbation of the underlying protein conformational ensemble. Effectively presenting epitopes using vaccines, to raise conformationally selective antibodies, is a central problem in treating neurodegenerative diseases. Parkinson’s and Alzheimer’s disease, which pathogenesis has been attributed to aberrant aggregates of α-synuclein and tau protein, respectively, are the two most common neurodegenerative diseases. Designing conformationally selective vaccines in silico often requires: 1.) an effective epitope scaffolding strategy that selectively targets pathologic aggregates known as oligomers while sparing the more abundant healthy monomers, with both the oligomeric and the monomeric forms having essentially identical amino acid sequences, and 2.) efficient methods and software for quantitative comparison of large conformational ensembles, which are currently not readily available.
In this thesis, we apply various computational techniques including those based on information theory and principles of physics to address these two challenges. We computationally modeled and designed cyclic peptide and β-helix protein vaccines to best mimic toxic oligomeric conformational ensembles of α-synuclein and tau protein computationally-predicted epitopes, respectively. In both Parkinson’s and Alzheimer’s disease, our designed vaccines are predicted to be conformationally selective for toxic oligomers. Additionally, we developed a new generalized method for efficient representation and comparison of protein conformational ensembles. The method is up to 88 times faster while utilizing 48 times fewer computing cores than the readily available Encore software on a molecular dynamics-generated ensemble dataset.
The methods developed and results presented in this thesis will not only accelerate the process of in silico conformation-specific vaccine design for protein aggregation-related diseases but have potential applications to antibody drug discovery and development in pharmaceutical biotechnology.
Event Location:
Hennings 318
Event Time:
Thursday, December 1, 2022 | 4:00 pm - 5:00 pm
Event Location:
HEBB 114
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2022-12-01T16:00:00
2022-12-01T17:00:00
Nanoaperture Tweezers: From Single Proteins to Single Quantum Emitters
Event Information:
Abstract:
There is a new class of technologies emerging for observing unmodified proteins in action and at the single molecule level. This colloquium will give an introduction to our nanoaperture optical tweezer approach and overview the developments from other groups also working in the area. I will also review our work on using these nanoapertures to isolate single Erbium emitters in nanocrystals for single photon sources at fiber optic communication wavelengths, and to study resonant energy transfer between two perovskite quantum dots.
Bio:
Dr. Reuven Gordon is a Professor of Electrical and Computer Engineering at the University of Victoria and a recent Canada Research Chair in Nanoplasmonics. Dr. Gordon is an expert in nanoplasmonics: the interaction of light with metal surfaces at tiny scales.
See Dr. Gordon's faculty webpage here: Reuven Gordon - University of Victoria (uvic.ca)
See Dr. Gordon's Nanoplasmonics Research Group here: Home (uvic.ca)
Event Location:
HEBB 114
Event Time:
Thursday, December 1, 2022 | 10:00 am - 11:00 am
Event Location:
BRIM 311
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2022-12-01T10:00:00
2022-12-01T11:00:00
CM Seminar: How Electron Hydrodynamics Can Eliminate the Landauer-Sharvin Resistance
Event Information:
Thomas Scaffidi - University of California Irvine
Title: How Electron Hydrodynamics Can Eliminate the Landauer-Sharvin Resistance
Abstract: What is the ultimate limit of conductance of a metallic device of lateral size W? In the ballistic limit, the answer is the Landauer-Sharvin conductance, which is associated with an abrupt reduction of the number of conducting channels when going from the contacts to the device. However, the ballistic limit is not always the best-case scenario, since adding strong electron-electron scattering can take electrons to a viscous regime of transport for which "super-ballistic" flows were recently studied. In this talk, we will show that by a proper choice of geometry which resembles a "wormhole", it is possible to spread the Landauer-Sharvin resistance throughout the bulk of the system, allowing its complete elimination by electron hydrodynamics. This effect arises due to the interplay between geometry and strong electron-electron scattering, which allows for a net transfer of carriers from reflected to transmitted channels. Finally, we will discuss a recent experiment in a Corbino geometry which realizes one half of this "wormhole" geometry.
Refs:
Theory: Phys. Rev. Lett. 129, 157701 (2022)
Experiment: Nature 609, 276–281 (2022)
Event Location:
BRIM 311
Event Time:
Monday, November 28, 2022 | 3:00 pm - 4:00 pm
Event Location:
HENN 318
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2022-11-28T15:00:00
2022-11-28T16:00:00
What can high-redshift, infrared-luminous galaxies tell us about galaxy formation physics and cosmology?
Event Information:
Abstract:
Interstellar dust is pervasive throughout the Universe, and most light from young, massive stars is absorbed by dust and reradiated as thermal emission in the infrared. Submillimeter galaxies (SMGs), a class of very infrared-luminous distant galaxies, are some of the most extreme star-forming galaxies known, forming stars at rates hundreds or even thousands of times greater than our own Milky Way. I will review our understanding of this enigmatic population, which has challenged galaxy formation theories since their discovery in the late 1990s. I will highlight how the population provides novel constraints on galaxy formation physics, cosmology, and possibly even the nature of dark matter. I will also show how they serve as beacons of galaxy clusters in the process of formation.
Bio:
I am a theorist who works to answer a wide variety of pressing open questions regarding galaxy formation. I emphasize bridging the gap between theory and observations by predicting observables from hydrodynamical simulations of galaxies through dust radiative transfer. I also do more traditional ‘pure’ theoretical work, ranging from developing an analytic theory for how stellar feedback simultaneously regulates star formation and drives outflows to magnetohydrodynamic simulations of galaxy mergers to detailed comparisons of numerical hydrodynamical methods and 'sub-resolution' implementations of crucial physical processes that cannot currently be treated ab initio in galaxy formation simulations, such as black hole growth.
I am currently an Associate Research Scientist at the Center for Computational Astrophysics, Flatiron Institute, which is funded by the Simons Foundation. Previously, I was a Moore Prize Postdoctoral Scholar in Theoretical Astrophysics at Caltech, where I primarily worked with Prof. Phil Hopkins. From December 2011 until July 2014, I was an independent postdoctoral scholar in Prof. Volker Springel’s group at the Heidelberg Institute for Theoretical Studies. In October 2011, I earned my PhD from Harvard; my supervisor was Prof. Lars Hernquist. Prior to starting at Harvard in September 2006, I spent a year in Cambridge, England, where I earned a Master of Advanced Study in Applied Mathematics and Theoretical Physics (with honors) for surviving Part III of the Mathematical Tripos. My undergrad years were spent at the University of Michigan, where I triple-majored in Astronomy & Astrophysics (highest honors), Physics, and Mathematics (high honors). I had the great fortune to start doing astrophysics research with Prof. Joel Bregman essentially as soon as I arrived at U of M, and I haven’t looked back since!
For more information, please see Dr. Hayward's research website here.
Event Location:
HENN 318
Event Time:
Monday, November 28, 2022 | 11:00 am - 12:00 am
Event Location:
HENN 318
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2022-11-28T11:00:00
2022-11-28T00:00:00
The future of gravitational wave detectors
Event Information:
TALK RECORDING AVAILABLE AT: https://drive.google.com/file/d/1is7783zB9tYQksLkmcAZ5E5NQu7mZvOP/view
Abstract
Just seven years after their first detection, gravitational waves (GWs) have revealed the first glimpses of a previously hidden dark Universe. Using the GW signature of distant compact-object collisions, we have discovered a new population of stellar remnants and unlocked new tests of general relativity, cosmology, and ultra-dense matter. How do we go further, and what might we learn when we do? I’ll discuss planned designs for future ground-based and space-based gravitational wave detectors, and the new science we will gain from detectors that can sense black hole collisions throughout cosmic time.
Event Location:
HENN 318
Event Time:
Thursday, November 24, 2022 | 4:00 pm - 5:00 pm
Event Location:
HEBB 114
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2022-11-24T16:00:00
2022-11-24T17:00:00
Accelerators as windows to the dark sector: the DarkLight experiment and the hunt for a new boson
Event Information:
Link to join remotely - look for today's date. The live stream will start at 4:00pm.
Abstract:
The nature of dark matter and its relationship to the Standard Model is one of the highest priority open questions in particle physics today. Accelerator-based experiments are a powerful tool in the search for dark matter and the new bosons that may mediate its interactions with the known particles. The DarkLight experiment will search for such a new boson with suppressed couplings to protons in an important uncovered low-mass range. DarkLight will be based at the TRIUMF electron linear accelerator and will pave the way for this unique machine to drive other future experiments.
Bio:
Kate is an experimental particle physicist whose research focuses on searches for new particles. She was a part of the ATLAS collaboration for more than 10 years but is now focusing on the new DarkLight experiment at TRIUMF. She got her BSc from the University of Victoria and her PhD from the University of Oxford. She worked as a postdoc first at Simon Fraser University and then at Duke University before beginning her current position as a TRIUMF research scientist.
For more information on the DarkLight project, see this article: DarkLight: a new particle search at TRIUMF.
Event Location:
HEBB 114
Event Time:
Thursday, November 24, 2022 | 10:00 am - 11:00 am
Event Location:
BRIM 311
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2022-11-24T10:00:00
2022-11-24T11:00:00
CM Seminar: Long Ju - Electron Correlation and Coupling with Phonon in the Trilayer Graphene/hBN Moire Superlattice
Event Information:
Long Ju – MIT Physics Department
Title: Electron Correlation and Coupling with Phonon in the Trilayer Graphene/hBN Moire Superlattice
Abstract: ABC-stacked trilayer graphene/hexagonal boron nitride moiré superlattice (TLG/hBN) has emerged as a playground for correlated electron physics. A spectroscopy study of this system is, however, challenging due to the device configuration. In this talk, I will introduce our recent efforts on FTIR photocurrent spectroscopy measurements of dual-gated TLG/hBN. We observed strong gate-tunable optical transitions that originated from the moire flat band. At half-filling of the valence flat band, a broad absorption peak emerges at ~18 meV, indicating direct optical excitation across an emerging Mott gap. Furthermore, I will talk about a unique moire-enabled interlayer electron-phonon coupling phenomenon in this system. The ZO phonon in hBN hybridizes with electron-hole excitations in trilayer graphene and appear as an asymmetric peak in the photocurrent spectrum. This Fano line-shaped peak evolves continuously as we tune the displacement field. I’ll talk about the implications of this phenomenon to engineering the physics of moire quantum matters.
Bio: Long Ju joined the MIT Physics Department as an assistant professor in January 2019. He received his B.S. in Physics in 2009 from Tsinghua University, China, and his Ph.D. in Physics in 2015 from the University of California, Berkeley. He then moved to Cornell University, where he was a Kavli postdoctoral fellow until December 2018.
Event Location:
BRIM 311
Event Time:
Wednesday, November 23, 2022 | 3:00 pm - 5:00 pm
Event Location:
https://ubc.zoom.us/j/61408939131?pwd=cGxvZDU4Zi9oTmVySjg1RTN2T1E5QT09, Passcode: 524103
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2022-11-23T15:00:00
2022-11-23T17:00:00
Radiative Capture and Decays in Ab Initio Nuclear Theory
Event Information:
Atomic nuclei exhibit many phenomena not limited to excited states, decays, reactions, and clustering. Nuclear processes control the evolution of stars and explain the abundances of chemical elements in the universe. Nuclear physics can be used to answer fundamental questions about underlying particle physics and cosmology, such as the symmetry between matter and antimatter or the nature of neutrinos. The discrepancy between theoretical predictions and observations motivates improved theory and can provide evidence for new physics. A predictive model of nuclei is needed as input for experimental tests and for astrophysical models.
Nuclei are complex strongly-interacting quantum many-body systems.
Accurate theoretical techniques are required to predict the rate of nuclear decay processes, the cross section of nuclear reactions and the distribution of the emitted particles. Ab initio nuclear theory takes advantage of the recent rapid increase in computing power to calculate nuclear structure and reactions solely from realistic interactions between the constituent nucleons.
In this thesis, we first present beta-decay calculations using the ab initio no-core shell model. Our calculations provide an explanation for the quenching of Gamow-Teller beta-decays, provide nuclear structure corrections to the beta-spectrum necessary to interpret experiments seeking to find new physics and provide estimates for the hypothetical process of neutrinoless double-beta decay. Second, we present radiative capture calculations using the no-core shell model with continuum, an extension which places bound and scattering states on equal footing. The rate of radiative capture reactions in big bang nucleosynthesis is required to estimate the abundance of isotopes in the early universe. In addition, anomalies in recent radiative capture experiments claim the discovery of a new boson. Comparing to these experiments requires prediction of the distribution of electron-positron pairs produced by radiative capture.
Event Location:
https://ubc.zoom.us/j/61408939131?pwd=cGxvZDU4Zi9oTmVySjg1RTN2T1E5QT09, Passcode: 524103
Event Time:
Monday, November 21, 2022 | 3:00 pm - 4:00 pm
Event Location:
HENN 318
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2022-11-21T15:00:00
2022-11-21T16:00:00
Machine Learning in the era of Time Domain Astronomy
Event Information:
Abstract:
Astronomy surveys like the Zwicky Transient Facility have been leading to discoveries that are orders of magnitude more than just a decade ago. The
discoveries range from the Solar System (comets, NEAs etc.) to Galactic science (CVs, YSOs, binaries etc.), to extragalactic (distant supernovae, AGN, TDEs) and possible EM counterparts to multi-messenger transients. We will provide an overview of the plethora of discoveries, and the ongoing work. We will describe our plans for ramping up discoveries even further with the aid of machine learning, especially by combining the archives with fresh alerts. With newer surveys, as we go fainter, cover more wavelengths, and go multi-messenger, more novel objects will be found. The rarity of these objects will both push the boundaries of our understanding, and also, due to the lack of statistically significant samples sometimes lead to premature claims, especially when using cutting-edge machine learning. We explore some aspects of time domain astronomy and its inherent biases, and comment on the requirement to explain the results through various techniques often involving post-hoc interpretability.
Find out more about Dr. Ashish Mahabal's research and work here: https://sites.astro.caltech.edu/~aam/
Event Location:
HENN 318
Event Time:
Monday, November 21, 2022 | 11:00 am - 12:00 pm
Event Location:
HENN 318
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2022-11-21T11:00:00
2022-11-21T12:00:00
Black hole evaporation in the Nariai limit
Event Information:
Abstract:
In 1974, Stephen Hawking proposed the existence of Hawking radiation -- blackbody radiation that carries energy away from a black hole. This is thought to be the mechanism behind the evaporation of black holes. But in order for evaporation to happen, the energy needs to be able to go somewhere that is not the black hole. This talk will focus on my on-going research into the evaporation of a 1+1D Schwarzschild-de Sitter spacetime in the limit where the black hole horizon and the de Sitter horizon are degenerate (known as the Nariai limit). We investigate the (de)focusing effects caused by the energy flux of a massless, conformally coupled scalar field using one-loop effective action techniques. At present, we find that the flux does not cause the degenerate horizon to split, suggesting that a SdS black hole in the Nariai limit is stuck there, and will not evaporate.
Event Location:
HENN 318
Event Time:
Thursday, November 17, 2022 | 4:00 pm - 5:00 pm
Event Location:
HEBB 114
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2022-11-17T16:00:00
2022-11-17T17:00:00
Cosmology, Galaxy Formation, and Planets with JWST
Event Information:
Link to join remotely - look for today's date. The live stream will start at 4:00pm.
Abstract:The modern standard cosmology ΛCDM describes almost perfectly the cosmic microwave background observations, but the resulting expansion rate of the universe (the Hubble parameter) is in serious disagreement with local measurements. This Hubble tension can perhaps be resolved by a brief episode of dark energy contributing about 10% of cosmic energy density for just a few thousand years about 50,000 years after the Big Bang. This high-redshift Early Dark Energy (EDE) scenario can be tested at lower redshifts, since new N-body simulations show that EDE predicts earlier structure formation than ΛCDM, for example 50% more clusters at redshift z ∼ 1 and 10x more galaxies at z ~ 10. Such predictions are being tested by new observations, including by James Webb Space Telescope. JWST’s infrared capabilities allow its cameras to see starlight from even the highest-redshift galaxies. JWST’s better resolution than Hubble Space Telescope is also revealing new aspects of galaxy and planet formation. Earth is a Goldilocks planet, in the Sun’s habitable zone and also with just the right amount of radioactive heating by thorium and uranium for a long-lived magnetic field and plate tectonics — both of which may be necessary for the evolution of complex life. Such Goldilocks exoplanets, taking into account the abundance of Th and U deduced from the star’s spectrum, should be among the first planets to be searched by JWST for biosignatures.
Bio:
Dr. Joel R. Primack specializes in the formation and evolution of galaxies and the nature of the dark matter that makes up most of the matter in the universe. After helping to create what is now called the "Standard Model" of particle physics, Primack began working in cosmology in the late 1970s, and he became a leader in the new field of particle astrophysics. His 1982 paper with Heinz Pagels was the first to propose that a natural candidate for the dark matter is the lightest supersymmetric particle. He is one of the principal originators and developers of the theory of Cold Dark Matter, which has become the basis for the standard modern picture of structure formation in the universe. With support from the National Science Foundation, NASA, and the Department of Energy, he has been using supercomputers to simulate and visualize the evolution of the universe and the formation of galaxies under various assumptions and comparing the predictions of these theories to the latest observational data. He organized and led the University of California systemwide Center for High-Performance AstroComputing (UC-HiPACC) 2010-2015.
Primack has received a multitude of accolades over the years (including the APS Forum on Physics and Society Award in 1977, APS 1988, AAAS 1995) and has served on numerous boards, executive committees and advisory panels including such organizations as the APS Division of Astrophysics, the Federation of American Scientists, AAAS Committee on Scientific Freedom and Responsibility, the AAAS Science and Human Rights program, the AAAS Program of Dialogue on Science, Ethics, and Religion and the National Academy of Sciences.
Primack was one of the main advisors for the Smithsonian Air and Space Museum's 1996 IMAX film Cosmic Voyage, and he has worked with leading planetariums to help make the invisible universe visible. In addition to more than 240 refereed technical articles in professional journals, Primack has written a number of articles aimed at a more popular audience.
For more information about Dr. Joel R. Primack, please see his UC Santa Cruz research website.
Event Location:
HEBB 114
Event Time:
Thursday, November 17, 2022 | 10:00 am - 11:00 am
Event Location:
BRIM 311
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2022-11-17T10:00:00
2022-11-17T11:00:00
CM Seminar: Professor Kai-Mei Fu - Quantum point defects: Can these defects be less defective?
Event Information:
Professor Kai-Mei Fu - University of Washington
Title: Quantum point defects: Can these defects be less defective?
Abstract: Point defects in crystals are the solid state analog to trapped ions. Thus these “quantum defects”, which can be integrated into solid-state devices, have gained popularity as qubit candidates for scalable quantum networks. In this talk, I will introduce some of the basic quantum defect properties desirable for quantum network applications. I will highlight my own group’s efforts at understanding and controlling the properties of defects in diamond including (1) synthesis, frequency and emission control of deep-level vacancy complexes in diamond and (2) properties of shallow-level donors in ZnO, including single donors and intentionally synthesized donors in ZnO.
Bio: Kai-Mei Fu is the Virginia and Prentice Bloedel Professor of Physics and Electrical and Computer Engineering at the University of Washington and holds a dual appointment with the Pacific Northwest National Laboratory. Kai-Mei received their PhD in Applied Physics in 2007 from Stanford University. Their research focuses on the synthesis, characterization and control of optically active quantum defects in crystals, with applications in quantum networks and sensing. At UW, Kai-Mei is the Director of UW’s NSF National Research Training Program: Accelerating Quantum-Enabled Technologies and the co-chair of UW’s interdisciplinary QuantumX Steering Committee. They are also the Deputy Director of the Department of Energy National Quantum Initiative (NQI) Co-design Center for Quantum Advantage. In their free time, Kai-Mei enjoys spending time with their family outdoors in the beautiful Pacific Northwest.
Event Location:
BRIM 311
Event Time:
Monday, November 14, 2022 | 3:00 pm - 4:00 pm
Event Location:
HENN 318
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2022-11-14T15:00:00
2022-11-14T16:00:00
Detecting Pulsars with Neural Networks
Event Information:
Abstract:
Pulsars are rotating neutron stars which emit faint beams of electromagnetic radiation. In pulsar searches large effort is expended to discover these pulses in time- and frequency-resolved data from radio telescopes. Simultaneously recovering the frequency-dependent delay (dispersion) and the periodicity of the signal is a complex and demanding task, which is further exacerbated by the presence of various types of radio-frequency interference (RFI) and observing-system effects.
I present a novel approach for the analysis of pulsar search data. I developed a neural-network-based pipeline that is able find pulsars directly in time- and frequency resolved data. The pipeline combines a convolutional neural network using dilated convolutions with standard algorithms for periodicity search such as the Fast Fourier Transform (FFT) and the Fast Folding Algorithm (FFA). This architecture can be trained in an end-to-end manner to identify faint pulses with an unknown amount of dispersion using a combination of simulated pulsars and unlabelled survey data as the training data. I present my training approach which allows the network to detect strong pulsars after a small amount of time and increase the sensitivity in subsequent training steps.
Bio:
Lars Künkel is a new post-doc here at PHAS.
email: lkuenkel@phas.ubc.ca
office: Hennings 324
Event Location:
HENN 318
Event Time:
Monday, November 14, 2022 | 11:00 am - 12:00 pm
Event Location:
HENN 318
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2022-11-14T11:00:00
2022-11-14T12:00:00
Quiet Coatings: Towards high throughput testing of mirror coating materials for gravitational wave detectors
Event Information:
TALK RECORDING AVAILABLE AT: https://drive.google.com/file/d/1mADq5Za4GFPS_9Y9er3nZivHHMcqEn_k/view?usp=share_link
Abstract:
Future generations of gravitational wave detectors will need improved mirror coatings so that they can be more sensitive than current detectors. These new mirror coatings must have a low mechanical loss so that they are as low noise – or as ‘quiet’ – as possible. There is a huge number of potential materials to test, so how can we do this testing quickly and efficiently, with as little material waste as possible? One approach, which I will present, is to miniaturize the devices onto which we put the coating materials. We can fabricate tiny mechanical microresonators, with hundreds of microresonators on one chip, and use these to measure coating loss via either free-space optics or integrated (on-chip) waveguides. I will give an overview of this work including device fabrication, the measurement technique and its unique advantages, and recent progress with our measurement system.
Event Location:
HENN 318
Event Time:
Thursday, November 10, 2022 | 10:00 am - 11:00 am
Event Location:
BRIM 311
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2022-11-10T10:00:00
2022-11-10T11:00:00
CM Seminar: Joyce Poon - Visible-light Silicon Integrated Photonics for Future Computing
Event Information:
Joyce Poon - Max Planck Institute of Microstructure Physics
Title: Visible-light Silicon Integrated Photonics for Future Computing
Abstract: The emerging demands of computing require hardware advances to realize new types of computing architectures and interfaces. Foundry silicon photonics leverages the maturity of microelectronics manufacturing to fabricate photonic integrated circuits. Today, silicon photonics is mostly used in the short-wave infrared spectrum for optical communications. I will discuss how foundry silicon photonics in the visible spectrum is an enabling technology for future computing, addressing applications such as displays, neural implants, and quantum computing.
Biography: Joyce Poon is the Managing Director at the Max Planck Institute of Microstructure Physics, a Professor of Electrical and Computer Engineering at the University of Toronto, and an Honorary Professor in the Faculty of Electrical Engineering and Computer Science at the Technical University of Berlin. She currently serves as a Director-at-Large for Optica (formerly the Optical Society, OSA). She and her team specialize in integrated photonics on silicon. Prof. Poon obtained the Ph.D. in Electrical Engineering from Caltech in 2007. She is a Optica Fellow and a Fellow of the IEEE.
Event Location:
BRIM 311
Event Time:
Monday, November 7, 2022 | 3:00 pm - 4:00 pm
Event Location:
HENN 318
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2022-11-07T15:00:00
2022-02-07T16:00:00
3D Hydrodynamic Simulations of Convection and Internal Gravity Waves in Massive Stars
Event Information:
Abstract:
It is quite satisfying to tackle old problems with new techniques and finally get answers that we previously thought impossible to get. I will report on our latest generation of simulations of massive main-sequence stars that finally reveal in unprecedented detail and realism the properties of the turbulent flow in the convective core and the topology of the convective boundary that consists of a substantial almost adiabatic penetration layer. Through these simulations we can also understand properties of recently discovered low-frequency power excess in asteroseismic satellite observations of massive stars and we can constrain mixing due to internal gravity waves excited in the stable layers above the convective core.
Bio:
Falk Herwig leads the Computational Stellar Astrophysics group to conduct research in a range of topics related to the evolution, hydrodynamics and nuclear astrophysics of stars and stellar explosions of single and binary stars. The CSA group participates in the NSF Physics Frontier Center Joint Institute for Nuclear Astrophysics - Chemical Evolution of the Elements and is an active member of the NuGrid collaboration. The CSA computational research is supported by Compute Canada high-performance computing time allocations on the Niagara supercomputer.
Dr Falk Herwig, Professor
Dept of Physics & Astronomy
University of Victoria
https://www.uvic.ca/research/centres/arc/people/faculty/herwig-falk.php
https://www.ppmstar.org
https://canpan.ca
Email: fherwig@uvic.ca
Tel: +1 (250) 721-7743
Twitter: @fherwig
Event Location:
HENN 318
Event Time:
Monday, November 7, 2022 | 11:00 am - 12:00 pm
Event Location:
HENN 318
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2022-11-07T11:00:00
2022-11-07T12:00:00
Decoherence of Matter by Infrared Radiation
Event Information:
Abstract:
In this talk, I will discuss how matter systems can lose quantum coherence by interacting with an environment consisting of low-energy photons or gravitons. This process will be illustrated using a simple model of an interferometry experiment. I'll focus particularly on how earlier results - which identified a relationship between "soft" photons/gravitons and boundary terms in the electromagnetic and gravitational matter currents - allows one to easily quantify precisely how much decoherence is caused by "leading" and "sub-leading" soft radiation.
Event Location:
HENN 318
Event Time:
Thursday, November 3, 2022 | 4:00 pm - 5:00 pm
Event Location:
HEBB 114
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2022-11-03T16:00:00
2022-11-03T17:00:00
Space Weapons and Challenges to Global Security
Event Information:
Link to join remotely - look for today's date. The live stream will start at 4:00pm.
Abstract:
Space plays a major role in society. Whether advancing science, communications, search and rescue, climate monitoring, weather tracking, resource management, navigation, or verification of international agreements, space-based infrastructure has become indispensable to our daily lives. Space has further facilitated international cooperation, even in the face of hostilities on Earth. Examples include the Apollo-Soyuz program, the International Space Station, COSPAS-SARSAT, and many international science-based missions. Yet, peace in space is not guaranteed. Indeed, as soon as nations began accessing space, they also began developing counterspace capabilities. Such capabilities include jamming or dazzling, which can temporarily deny users access to space-based assets. But they also include cyberattacks, disabling ground-based infrastructure, and the intentional destruction of satellites. In this talk, I will first provide a short overview of many challenges we face in the sustainable development of space. I will then focus on the growing concern of conflict in space, including past and present space weapon tests. We will also discuss how a security dilemma is emerging from new stages of space exploration, particularly with plans for sustained lunar programs. Fortunately, there are ongoing international processes working to establish norms of behaviour in space and avoid conflict, with the aim to keep the use of space for peaceful purposes only.
Bio:
Dr. Boley is an Associate Professor in the Department of Physics and Astronomy at UBC, a Canada Research Chair in Planetary Astronomy, and co-founder and co-director of the Outer Space Institute, which focuses on the sustainable development of Space.
Event Location:
HEBB 114
Event Time:
Thursday, November 3, 2022 | 10:00 am - 11:00 am
Event Location:
BRIM 311
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2022-11-03T10:00:00
2022-11-03T11:00:01
CM Seminar: Professor Romain Vasseur - Anomalous Diffusion in Quantum Spin Chains
Event Information:
Professor Romain Vasseur – University of Massachusetts, Amherst
Title: Anomalous diffusion in quantum spin chains
Abstract: High-temperature quantum transport is usually assumed to be incoherent and diffusive. In this talk, I will explain how anomalous transport in quantum spin chains can emerge from proximity to special integrable limits, due to a hierarchy of long-lived quasiparticle excitations. I will summarize our understanding of finite-temperature transport in integrable spin chains, and argue that integrability-breaking perturbations can generically lead to either super- or subdiffusion up to very long-time scales.
Bio: Romain Vasseur is an Associate Professor in the Physics Department of the University of Massachusetts, Amherst. He is a condensed matter theorist working on strongly correlated quantum systems and quantum information, with a focus on the interplay of strong interactions and quantum entanglement, leading to new emergent phenomena both in thermal equilibrium and in non-equilibrium quantum systems. Before moving to Amherst, Dr. Vasseur was a Postdoctoral Fellow at Lawrence Berkeley National laboratory (2013-2017), working in the Condensed Matter Theory Center at the University of California, Berkeley. He obtained his PhD at IPhT (CEA, Saclay) and LPTENS (ENS, Paris) in 2013. Prof. Vasseur has been recognized as a fellow of the Alfred P. Sloan Foundation (2019) and an Early Career Award of the US Department of Energy (2018). He is also the recipient of a Young Investigator Award of the US Air Force Office of Scientific Research (2020).
Event Location:
BRIM 311
Event Time:
Monday, October 31, 2022 | 3:00 pm - 4:00 pm
Event Location:
HENN 318
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2022-10-31T15:00:00
2022-10-31T16:00:00
How to take direct images of Exoplanets?
Event Information:
Abstract:
Exoplanets are planets that orbit stars other than the Sun. As of today, more than 5000 exoplanets have been discovered in our Milky Way galaxy alone. NASA’s statistics state that each of the 300 billion stars in our galaxy has at least one planet orbiting it. Such exoplanet discoveries are already helping us to understand how planets form and evolve and what the atmospheres of exo-worlds look like, however, finding signs of life outside of Earth is still an unachievable feat.
One way to find exoplanets is the direct imaging method, which translates into taking family portraits of extra-solar systems using the current ground-based telescopes (5-10-meters). Exoplanets are roughly thousand to ten billion times fainter than their stars and finding such dim signals in the presence of overwhelmingly bright stars is technically challenging. Moreover, the light of a star-planet pair that traverses through the Earth is blurred by the atmospheric layers of different temperatures, humidity, and wind speeds. The structure of telescopes also vibrates due to the motion of motors and local wind, which collectively, makes it difficult to disentangle exoplanetary signals from the starlight. This makes direct imaging biased towards finding exoplanets that shine their own light and reside far away (farther than Sun-Saturn distance) from their parent stars. The first and foremost requirement for capturing signs of life is to find closer-in exoplanets by overcoming the technical challenges faced by state-of-the-art direct imaging instruments. In this talk, I will discuss how the current instruments overcome these challenges and acquire images of exoplanets. I will also discuss the cutting-edge research being performed at NRC-HAA to improve the performance of such instruments.
Find out more about Dr. Garima Singh's research and work here: https://guiding-honu.github.io/GarimaSingh/profession/
Event Location:
HENN 318