Events List for the Academic Year
Event Time:
Thursday, February 2, 2023 | 10:00 am - 11:00 am
Event Location:
BRIM 311
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2023-02-02T10:00:00
2023-02-02T11:00:00
CM Seminar: Patrick Ledwith – Harvard University: Vortexability Chern bands in Twisted and Strained Graphene
Event Information:
Patrick Ledwith – Harvard University
Title: Vortexability Chern bands in Twisted and Strained Graphene
Abstract: Fractional Chern insulators realize the remarkable physics of the fractional quantum Hall effect (FQHE) in crystalline systems with Chern bands. The lowest Landau level (LLL) is known to host the FQHE, but not all Chern bands are suitable for realizing fractional Chern insulators (FCI). Previous approaches to stabilizing FCIs focused on mimicking the LLL through momentum space criteria. Here instead we take a real-space perspective by introducing the notion of vortexability. Vortexable Chern bands admit a fixed operator that introduces vortices into any band wavefunction while keeping the state entirely within the same band. Vortexable bands admit trial wavefunctions for FCI states, akin to Laughlin states. In the absence of dispersion and for sufficiently short ranged interactions, these FCI states are the ground state -- independent of the distribution of Berry curvature. Vortexable Chern bands were found to emerge naturally in chiral twisted graphene, and fractional Chern insulators were subsequently observed experimentally. They were also recently proposed in periodically strained graphene.
Bio: Patrick Ledwith grew up near Philadelphia, Pennsylvania. He got his undergraduate degree in Physics and Mathematics at MIT. There he worked with Leonid Levitov on electron hydrodynamics, discovering and elucidating long-lived collective excitations in two-dimensional electron gases. He is now a graduate student working in Ashvin Vishwanath's group. Here he has worked on several aspects of moiré materials including fractional Chern insulators, superconductivity, correlated insulators, and topological charge density waves. He has been especially interested in developing analytic approaches to fractional Chern insulators. He has applied these methods to twisted bilayer graphene where they work especially well. He subsequently partnered with Amir Yacoby's group in realizing and understanding experimentally observed fractional Chern insulating states at small magnetic fields. In his free time, he likes to cook and play video games with his dog.
Event Location:
BRIM 311
Event Time:
Monday, January 30, 2023 | 3:00 pm - 4:00 pm
Event Location:
HENN 318
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2023-01-30T15:00:00
2023-01-30T16:00:00
Betelgeuse Is Pretty Cool: Cosmic Questions for our Naked-Eye Neighbor
Event Information:
Abstract:
Betelgeuse's "Great Dimming" in the winter of 2020 quickly became a source of fascination for both professional and amateur astronomers. Drastic enough to be easily detected with the naked eye, the star's drop in brightness was unprecedented in observational memory and revealed the extent to which the workings of red supergiants (RSGs) are still a mystery. RSGs are the coldest and physically-largest members of the massive star population, making them ideal sources for studying the extremes of stellar physics and a key turning point in the evolution of post-main-sequence massive stars. They are also the progenitors of Type II-P supernovae, an intermediate evolutionary phase in the lifetimes of some stripped-envelope supernova progenitors, and a crucial step in the formation of massive binary systems (including those that will ultimately produce compact object binaries and gravitational waves). However, our recent studies of Betelgeuse have forced us to confront the many unanswered questions that still surround RSGs, including their binary fraction and evolution, their place in the larger picture of massive star evolution, and the numerous physical phenomena that drive their variability. Using Betelgeuse and its recent behavior as an archetype, this talk will provide an overview of our current knowledge of RSGs, identify some of the most pressing open questions about these stars, and consider the importance of studying RSGs in the coming decade as the next generation of observatories comes online.
Bio:
Ph.D., Astronomy, University of Hawaii, 2010
S.B., Physics, MIT, 2006
Emily Levesque’s research interests are focused on massive stellar astrophysics and the use of massive stars as cosmological tools. Her current research program includes panchromatic observations and models of star-forming galaxies and their young stellar populations; host galaxy and progenitor studies of massive star transients such as LBVs, supernovae, and long-duration gamma-ray bursts; surveys of evolved massive stars in and beyond the Local Group; and the properties of Thorne-Zytkow objects.
To find our more, please see Emily's website here.
Event Location:
HENN 318
Event Time:
Monday, January 30, 2023 | 11:00 am - 12:00 pm
Event Location:
Henn 318
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2023-01-30T11:00:00
2023-01-30T12:00:00
Follow-up searches for persistent gravitational waves in O3 LIGO data using a hidden Markov model
Event Information:
TALK RECORDING AVAILABLE AT: https://drive.google.com/file/d/12vZ2TNlzaWh3DPdC90Q_vty9crJumDQ3/view?usp=share_link
Abstract:
Continuous waves (CWs) are an as-yet undiscovered class of gravitational waves, characterized as long-lived and nearly monochromatic signals. CWs are believed to be produced by rapidly spinning neutron stars, possibly due to tiny deformations on the neutron star crust (“mountains”), or due to unstable stellar oscillation modes such as r-modes. Present-day gravitational-wave detectors, including Advanced LIGO and Advanced Virgo, may be able to detect CWs from such sources located in our galaxy. CW searches must contend with several challenges, including significant computing requirements and difficulties in accurately modeling the sources of these waves. In this talk, I will discuss basic continuous-wave data analysis, with an emphasis on applying hidden Markov models (HMMs) and frequency tracking to CW searches. I will highlight a semi-coherent search pipeline which I and others have been working on, which leverages HMM techniques to perform follow-up of sub-threshold candidates identified by the LIGO All-Sky All-Frequency radiometer analysis, using LIGO data from the third observing run (O3).
Event Location:
Henn 318
Event Time:
Thursday, January 26, 2023 | 4:00 pm - 5:00 pm
Event Location:
Zoom only
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2023-01-26T16:00:00
2023-01-26T17:00:00
STEP UP: Supporting Teachers to Encourage the Pursuit of Undergraduate Physics for Women
Event Information:
Abstract:
In the US, nearly half of students taking physics in high school are women, but only a fifth of the students interested in physics majors in college are women. This issue has persisted over decades. As such, the STEP UP project (www.stepupphysics.org) launched a nationwide initiative in the US to mobilize and help physics educators better engage women in physics by disrupting narrow perceptions of physics and promoting supportive classroom cultures. This talk will present some of the research evidence used by STEP UP to develop, test, and promote strategies that facilitate the physics identity development and future physics intentions of young women. These evidence-based strategies are being used by physics educators as part of the national campaign, which has grown to include a network of more than three thousand physics teachers, faculty, students, and community members, to inspire a new generation of women physicists. (Supported by the Moore Foundation and National Science Foundation under Grant No. 1720810, 1720869, 1720917, and 1721021).
Bio:
Zahra Hazari is a Professor in the Department of Teaching & Learning and STEM Transformation Institute as well as affiliate faculty in the Department of Physics at Florida International University. She holds a B.S. in physics and mathematics, M.S. in physics, and Ph.D. in physics education. Her doctoral and postdoctoral work were at the University of Toronto and the Harvard Smithsonian Center for Astrophysics. Dr. Hazari’s research focuses on reforming physics learning environments in an effort to improve inclusivity for marginalized groups in physics, especially women. This work has led to her being elected a fellow of the American Physical Society (APS) and earned her a National Science Foundation (NSF) CAREER Award. She has served on several Editorial Boards (Physical Review PER, JRST, AERJ) and Committees for Women in Physics (APS, AAPT).
See more on Dr. Hazari's website page: Zahra Hazari | College of Arts, Sciences & Education | Florida International University (fiu.edu)
Event Location:
Zoom only
Event Time:
Thursday, January 26, 2023 | 10:00 am - 11:00 am
Event Location:
BRIM 311
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2023-01-26T10:00:00
2023-01-26T11:00:00
CM Seminar: Dr. Alannah Hallas - Entropy engineering and tunable magnetic order in the spinel high entropy oxide
Event Information:
Dr. Alannah Hallas - UBC
Title: Entropy Engineering and Tunable Magnetic Order in the Spinel High Entropy Oxide
Abstract: The field of high entropy oxides (HEOs) flips traditional materials science paradigms on their head by seeking to understand what properties arise in the presence of profound configurational disorder. This disorder, which emerges as the result of multiple elements sharing a single crystalline lattice, can take on a kaleidoscopic character due to the vast numbers of possible elemental combinations and appears to imbue some HEOs with functional properties that far surpass their conventional analogs. While experimental discoveries abound, efforts to characterize the true magnitude of the configurational entropy and understand its role in stabilizing new phases and generating superior functional properties have lagged behind. Understanding the role of configurational disorder in existing HEOs is the crucial link to unlocking the rational design of new HEOs with targeted properties. In this talk, I will discuss our group's efforts to establish a framework for articulating and beginning to address these questions towards achieving a complete understanding of the true role of entropy in HEOs.
Bio: Alannah Hallas is an Assistant Professor in the Department of Physics & Astronomy at UBC, a Principal Investigator at the Stewart Blusson Quantum Matter Institute, and a CIFAR Azrieli Global Scholar in Quantum Materials. Alannah’s research program is focused on the design, discovery, and crystal growth of new quantum materials, leveraging a wide range of advanced crystal growth techniques. Her group characterizes the quantum magnetic properties of their materials using x-ray and neutron scattering as well as muon spin relaxation techniques.
Event Location:
BRIM 311
Event Time:
Wednesday, January 25, 2023 | 10:00 am - 12:00 pm
Event Location:
https://ubc.zoom.us/j/64229865355?pwd=d2RFMlh2eGlUUThOTW8zN0RIMGpFUT09
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2023-01-25T10:00:00
2023-01-25T12:00:00
Collective Modes of the Superconducting Condensate
Event Information:
When a continuous symmetry is spontaneously broken, collective modes emerge. Usually, their spectrum is dominated by the low-energy physics of massless Goldstone modes. Superconductors, that break U(1) symmetry, are different. Here, the Goldstone boson is gapped out due to the Anderson-Higgs mechanism. The superconducting condensate can therefore host a zoo of massive collective excitations that are stable for lack of a gapless decay channel. The most prominent of them is the Higgs mode. Spectroscopy of collective modes can be a probe to reveal the nature of the superconducting state. In this thesis, we study the signatures of collective modes in nonlinear optical experiments. We ex- plore the theoretical description of a new excitation scheme. We show how impurity scattering significantly enhances the optical Higgs mode response. We apply group theoretical methods to multi-order-parameter theories and investigate the microscopic signature of coupled modes in third harmonic generation experi- ments. Finally, we study the phenomenology and collective mode spectrum of an exotic system of twisted cuprate bilayers that supports topological superconductivity.
Event Location:
https://ubc.zoom.us/j/64229865355?pwd=d2RFMlh2eGlUUThOTW8zN0RIMGpFUT09
Event Time:
Monday, January 23, 2023 | 3:00 pm - 4:00 pm
Event Location:
HENN 318
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2023-01-23T15:00:00
2023-01-23T16:00:00
Next-generation gravitational-wave astronomy: challenges and opportunities
Event Information:
Abstract:
The observation of compact binary mergers by the LIGO/Virgo/KAGRA collaboration marks the dawn of a new era in astronomy. Next-generation ground-based detector (Cosmic Explorer and the Einstein Telescope) will allow us to peer far deeper, and LISA will expand our gravitational wave "senses" by opening a new window at low frequencies. Observations of the gravitational waves emitted by compact binary systems in these two frequency windows can lead to new astrophysical insights and new tests of strong-field gravity. I will highlight some of the new challenges and opportunities presented by next-generation detectors. If time allows it, I will discuss: (i) the challenges of parameter estimation in the presence of waveform systematics and multiple overlapping sources, (ii) improvements in tests of general relativity, and (iii) the current observational status of black hole spectroscopy.
Bio:
Emanuele Berti received a Ph.D. from the University of Rome "La Sapienza” in 2002. He held postdoctoral positions at the Aristotle University of Thessaloniki, the Institut d’Astrophysique de Paris, Washington University in Saint Louis, and JPL/Caltech. He joined the faculty at the University of Mississippi in 2009, and he moved to Johns Hopkins as professor in 2018.
Berti is a theoretical physicist who specializes in gravitational physics and gravitational-wave astronomy. His research interests include the structure, stability, dynamics and formation of black holes and neutron stars; gravitational-wave signatures of modified theories of gravity and physics beyond the Standard Model; using gravitational waves to understand black hole binary astrophysics and cosmology; and preparing for the challenge of detecting gravitational waves in space with LISA.
Berti is a Fellow of the American Physical Society (APS) and of the International Society on General Relativity and Gravitation (ISGRG). He served on the Chair line of the APS Division of Gravitational Physics (2016-2019) and he is currently President Elect of the ISGRG. He is also a Divisional Associate Editor in Gravitational Physics for Physical Review Letters, and a member of NASA’s U.S. LISA Study Team.
Please see Dr. Berti's webpage here.
Event Location:
HENN 318
Event Time:
Monday, January 23, 2023 | 11:00 am - 12:00 am
Event Location:
Henn 318
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2023-01-23T11:00:00
2023-01-23T00:00:00
Beyond standard sirens: Gravitational wave cosmology without electromagnetic counterparts
Event Information:
Mervyn Chan (mervync@phas.ubc.ca)
**We welcome everyone to this event, from upper-level undergraduate students, post-docs and faculty to the general public. Come join us!**
Event Location:
Henn 318
Event Time:
Thursday, January 19, 2023 | 4:00 pm - 5:00 pm
Event Location:
HENN 201
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2023-01-19T16:00:00
2023-01-19T17:00:00
Testing Fundamental Physics with the Event Horizon Telescope
Event Information:
Abstract:
New horizon-scale images of the Galactic Center black hole Sagittarius A* (Sgr A*) recently published by the Event Horizon Telescope (EHT) allow for new strong-field tests of the Kerr metric in a previously unexplored regime. I will discuss the recent EHT observations of Sgr A* with a particular focus on how these new results can be used to test fundamental physics. I will briefly touch upon the earlier M87 results as well.
Bio:
Dr. Medeiros is a computational high-energy astrophysicist interested in compact objects. She completed her undergraduate education at the University of California-Berkeley in Physics and Astrophysics, then received her Masters and PhD in Physics from the University of California-Santa Barbara. During her PhD, she spent three years at the Steward Observatory at The University of Arizona and one year at the Black Hole Initiative at Harvard. Dr. Medeiros then went on to an NSF Astronomy and Astrophysics Postdoctoral Fellowship, and is currently a 5-year member of the IAS at Princeton.
Find out more about Lia's research, publications and public speaking topics, here: Lia Medeiros, Phd.
For more information about the Event Horizon Telescope, please see here: Event Horizon Telescope
Event Horizon Telescope Press Release (April 10, 2019): Astronomers Capture First Image of a Black Hole: Press Release (April 10, 2019): Astronomers Capture First Image of a Black Hole | Event Horizon Telescope
Chandra X-Ray Observatory: "Sagittarius A*
Event Location:
HENN 201
Event Time:
Thursday, January 19, 2023 | 10:00 am - 11:00 am
Event Location:
BRIM 311
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2023-01-19T10:00:00
2023-01-19T11:00:00
CM Seminar: Prof. Mark Rudner - University of Washington
Event Information:
Prof. Mark Rudner - University of Washington
Title: “The Lindblad Quantum Master Equation: Not Just for quantum Optics Anymore"
Abstract: With the exception of the universe as a whole, the evolution of a quantum system is generically non-unitary due to the coupling between the system and its environment. In quantum optics, the powerful framework of Lindblad master equations has been developed and employed for many years to describe the effective evolution of atomic-like systems in the presence of electromagnetic and other environmental degrees of freedom. Importantly, explicit derivations of Lindblad master equations have traditionally relied on highly restrictive assumptions on energy level spacings that limit its applicability to few-level/few-body systems. In this talk I will review the basic features of evolution of open quantum systems, and describe a new route to obtaining the Lindblad equation which circumvents all restrictive assumptions on the nature of the system at hand. This "universal Lindblad equation" can therefore be applied to a wide range of many-body systems, including emerging quantum hardware with several to many coupled qubits and many-body systems driven far from equilibrium. The explicit expressions for the "jump operators" that describe incoherent processes induced by the bath have a natural interpretation in terms of an operator spreading picture, akin to that which has recently provided much insight into thermalization of closed quantum systems. I will conclude with a discussion of future prospects and applications of this new framework.
Bio: Mark Rudner is the Kenneth K. Young Memorial Professor of Physics at the University of Washington. His research interests span a broad range of topics in theoretical condensed matter physics and quantum dynamics. Following his PhD at MIT, in which he studied classical and quantum control in solid state spin and superconducting qubits, as well as transport in graphene, in 2008 Mark moved to Harvard for a postdoctoral fellowship. During this time, he developed foundational works on topological phenomena in both driven ("Floquet") and open (non-Hermitian) quantum systems. In 2012, Mark moved to Copenhagen, where he joined the Center for Quantum Devices at the Niels Bohr Institute and took charge of the Condensed Matter Theory group at the Niels Bohr International Academy. Over the next decade, Mark maintained a role as one of the leaders in the emerging fields of Floquet engineering and non-equilibrium quantum dynamics, while further exploring novel (linear and non-linear) collective phenomena that arise from the interplay of quantum geometry and interparticle interactions. In 2021 Mark joined the University of Washington, where he is continuing these efforts while expanding into new directions in collaboration with his experimental and theoretical colleagues.
Event Location:
BRIM 311
Event Time:
Tuesday, January 17, 2023 | 9:45 am - 11:00 am
Event Location:
Henn 318
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2023-01-17T09:45:00
2023-01-17T11:00:00
Special Gravity Seminar: Hydrodynamic rotating black holes
Event Information:
Abstract:
We will discuss experimental results studying the wave-vortex interaction arising from rotating fluid
and superfluid flows. The dynamical equation describing the wave-vortex interaction can be mapped to
scalar fields propagating on an effective rotating black hole. This opens the possibility of studying a
variety of rotating black hole processes in hydrodynamic systems. I will summarise our experimental
efforts resulting in the detection of geodesic motion, quasi-normal modes and superradiance in normal
fluids at room temperature and pressure. I will end by introducing by presenting our new experimental
system, based on superfluid optomechanics, allowing us to study rotating black hole effects in the
quantum domain.
Event Location:
Henn 318
Event Time:
Monday, January 16, 2023 | 3:00 pm - 4:00 pm
Event Location:
Henn 318
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2023-01-16T15:00:00
2023-01-16T16:00:00
Quantum Spacetime in the Cosmos: The Endgame
Event Information:
Abstract:
The past century of progress in Physics and Astronomy has witnessed development of hugely successful programs in theory, observations, experiments, and phenomenology. While it is perfectly justified to celebrate these advances, we must not lose sight of the big picture, one that includes ever-widening chasms amongst our best models of nature: dark matter, vaccum, the big bang, particle physics and quantum gravity. Will either observations or experiments ever be able to bridge these divides, or are we still missing key analytic ingredients? Do we even have the right language or tools? I will ponder these deep questions, and what I see as trickles of hope for an endgame.
Bio:
Dr. Niayesh Afshordi is a professor in the Astrophysics and Gravitation group at the Department of Physics and Astronomy, University of Waterloo, Associate Faculty in the Cosmology and Gravitation group at the Perimeter Institute for Theoretical Physic (PI) and founding faculty member at the Waterloo Centre for Astrophysics (WCA).
"I dabble in Astrophysics, Cosmology, and Physics of gravity. I am obsessed with observational hints that could help address problems in fundamental physics. In particular, I have found anomalous signatures of dark energy and dark baryons in the cosmic microwave background radiation. With other collaborators, I have also developed a curious theory for an incompressible dark energy, named cuscuton (after the Latin name for the parasitic plant of dodder). I am currently trying my hand in solving the cosmological constant problem through a new theory of gravity that can surprisingly relate the formation of astrophysical black holes to today’s acceleration of cosmic expansion. In a related inquiry, I am also exploring the relation of cuscuton and quantum gravity. My most exciting discoveries (so far) might be the Cosmological non-Constant problem, the most predictive theory of Big Bang, or Echoes from the Abyss!" Find out more about Dr. Afshordi's research and interests here.
Find research publications here. You can also find public talks, popular articles and youtube videos here.
Event Location:
Henn 318
Event Time:
Monday, January 16, 2023 | 11:00 am - 12:00 pm
Event Location:
HENN 318
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2023-01-16T11:00:00
2023-01-16T12:00:00
Non-linear Horndeski analysis with Hi-COLA
Event Information:
TALK RECORDING AVAILABLE AT: https://drive.google.com/file/d/15V37wrgQQb0mN6MrBIZ9dQhZZeqYgWDI/view?usp=share_link
Abstract:
Upcoming data from surveys such as the Legacy Survey of Space and Time (LSST) will give us some of the first opportunities to probe the behaviour of gravity on non-linear scales. Such data will prove to be invaluable in constraining the space of modified gravity theories with screening mechanisms, properties of these theories that cause them to behave like General Relativity in regions where the local energy density is high (such as the Solar system), which manifest on non-linear scales. Thus, there is a need to be able to produce predictions for such theories in order to compare with observations - and this is what Hi-COLA (Horndeski-in-COLA) aims to do. Hi-COLA is an approximate simulation code designed to produce matter power spectra valid on mildly non-linear scales for a wide class of Horndeski theories for the first time, and at low computational cost. I will discuss how Hi-COLA works, and the conclusions about the clustering behaviour of Horndeski theories we have derived through our usage of Hi-COLA.
Event Location:
HENN 318
Event Time:
Monday, January 16, 2023 | 10:30 am - 12:30 pm
Event Location:
https://ubc.zoom.us/j/63397566153?pwd=MEgyK0JvaFIyb1JLSWxrV3I5UWo3QT09
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2023-01-16T10:30:00
2023-01-16T12:30:00
Development of statistical tools for studies of the astrophysical rapid neutron capture process
Event Information:
Abstract:
The rapid neutron capture process (r-process) is a complex nucleosynthesis mechanism for the creation of heavy nuclei, which occurs under extreme astrophysical conditions, such as binary neutron star mergers and some types of core-collapse supernovae. An accurate understanding of the r-process is crucial for explaining the abundances of roughly half the elements heavier than iron in the solar system. Not only are the predictions of the r-process abundance pattern affected by the thermodynamical conditions of such astrophysical events, significant uncertainty also arises from the properties of thousands of neutron-rich nuclides involved in the process. While many of the neutron-rich nuclei may become experimentally accessible in the near future, it is essential to quantify the uncertainty originating from theoretical descriptions of atomic nuclei and identify key nuclear physics inputs of the numerical simulations of the r-process.
In this thesis, several statistical methods have been applied to tackle the uncertainty of nuclear physics inputs in the studies of the r-process nucleosynthesis. Variance-based sensitivity analysis method identifies influential nuclear physics inputs in a statistically rigorous manner and probes their effect on elemental abundance patterns. Ensemble Bayesian model averaging method provides a simple framework for combining competing theoretical nuclear physics models based on experimental data and quantifying their uncertainty. Furthermore, emulation of r-process abundance calculations has been performed using artificial neural networks, which dramatically speeds up the calculations of abundance patterns, potentially allowing for scaling up various statistical analyses. While the effectiveness of these methods has been shown for the specific features of the observed solar abundance pattern and nuclear physics observables, they are readily applicable to broader aspects of the studies of the r-process nucleosynthesis.
Event Location:
https://ubc.zoom.us/j/63397566153?pwd=MEgyK0JvaFIyb1JLSWxrV3I5UWo3QT09
Event Time:
Monday, December 12, 2022 | 3:00 pm - 4:00 pm
Event Location:
HENN 318
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2022-12-12T15:00:00
2022-12-12T16:00:00
Recent Developments in Instruments for High Redshift 21cm and Exoplanets
Event Information:
Abstract:
Being an introduction and a status report on HERA the 21cm array, the SPARCS M-dwarf exoplanet-host flare monitor cubesat, and space-based testing of 21cm instruments.
Observation of 21cm radio emission from neutral hydrogen from before reionization is a promising window on the early universe and has received considerable experimental attention. The Hydrogen Epoch of Reionization Array (HERA) has reported limits which constrain galaxy formation models and is now observing after an upgrade. I will review these improvements. An essential 21cm experiment is its location; almost nowhere on Earth is suitable. Longer wavelengths can only be observed from space. The same is true in the ultraviolet. Recent advances have encouraged a new generation of UV instruments. Stellar flares, which are extremely bright in the UV, have a strong impact on the atmospheres of exoplanets. The Star Planet Activity Research CubeSat (SPARCS) will monitor flare M-Dwarf stars, one of the most common planet host. This cubesat is currently under construction aiming for a launch in early 2024. I will describe the design and some interesting particulars of this miniature space telescope. The lessons and technical capability we are building with SPARCS are training us for a future of space-based radio observations. The first such experiment will be the DORA cubesat which carries a prototype 21-cm receiver set to launch Dec 2023.
Bio:
Danny Jacobs is an Assistant Professor at the School of Earth and Space Exploration at Arizona State University, co-director of the Low Frequency Cosmology lab studying high redshift cosmology at low radio frequencies, and Associate Director of the ASU Interplanetary Initiative where he serves as Director of the II Lab which supports cubesats and other small space missions.
For more information, please visit Danny's homepage.
Event Location:
HENN 318
Event Time:
Monday, December 12, 2022 | 11:00 am - 12:00 pm
Event Location:
HENN 318
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2022-12-12T11:00:00
2022-12-12T12:00:00
Searching for compact binary coalescences using gravitational waves
Event Information:
TALK RECORDING AVAILABLE AT: https://drive.google.com/file/d/1ozuIcU_1hSFvQL-3egYoTBEkIIlMsbSi/view?usp=share_link
Abstract:
With nearly a hundred confident detections over three observing runs, we are well into the era of gravitational wave astronomy. As the upcoming observing run (scheduled to begin in spring 2023) approaches, we are poised to make even more detections of gravitational waves from black holes and neutron stars merging far beyond our galaxy. In this talk, I will provide an overview of gravitational waves and then discuss current techniques for detecting gravitational wave events from compact binary coalescences that will be used by the LIGO, Virgo, and KAGRA detectors in the next observing run.
Event Location:
HENN 318
Event Time:
Friday, December 9, 2022 | 1:30 pm - 3:30 pm
Event Location:
Henn 318
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2022-12-09T13:30:00
2022-12-09T15:30:00
Biophysics of disease and evolution: Molecules to Organisms
Event Information:
This thesis describes applications of computer simulation and bioinformatics techniques in conjunction with experiments to understand various biological systems.
In Chapter 2, we used molecular dynamics simulations to uncover the structural details of an experimentally observed interaction between the ALS-associated protein superoxide dismutase 1 (SOD1), and TNF receptor-associated factor 6. Residues present in their heterodimer binding interface were predicted through unbiased and metadynamics simulations and tested in cultured cells.
In Chapter 3, we used a quick computational scan to identify two de novo mutations of SOD1, A89R and K128N that were expected to be destabilizing and stabilizing respectively. Expression in cell cultures and zebrafish confirmed that A89R produces pathologies similar to the ALS-associated mutant A4V, and that K128N is WT-like. Interestingly, unlike WT-SOD1, K128N rescued the aberrant phenotype of zebrafish motor neurons when coinjected with A4V-SOD1. To explain this, we used computational alchemy to calculate heterodimerization free energies for A4V-SOD1 with WT-SOD1 and K128N-SOD1, but could not confirm a "heterodimer-rescue" mechanism.
In Chapter 4, we studied the conformational landscape of the SARS-CoV-2 spike protein. The conserved residues 980--990, normally buried under the receptor binding domain, have been reported to be transiently accessible to antibodies. Through umbrella sampling simulations we found that direct exposure of the epitope through dynamic motions is not a likely mechanism for this accessibility. Further, glycans play an important role in preventing such dynamics. During its normal function, this epitope undergoes a large-scale conformational change from a bent to an extended state. To aid development of a vaccine antigen containing the conserved fragment, we studied the free energy cost of this change and found that a bent pre-fusion-like conformation is preferred.
Moving on from protein studies, in Chapter 5 we were interested in the biophysics of genome organization, and its evolution in early ancestors of all animals. The basal metazoan Mnemiopsis leidyi is well-suited for such studies but has not been standardized as a model organism. We developed protocols for laboratory culture of this organism, and obtained a highly contiguous reference genome for an inbred lineage.
Event Location:
Henn 318
Event Time:
Friday, December 9, 2022 | 8:30 am - 10:30 am
Event Location:
https://ubc.zoom.us/j/62811600818?pwd=WlJyS09SQ0gva3EwZ1N3dmNDdmZlQT09 Passcode: 459642
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2022-12-09T08:30:00
2022-12-09T10:30:00
Magnetic resonance imaging to measure myelin: orientation dependence and application to spinal cord injury
Event Information:
Myelin, the lipid-rich sheath which wraps around axons, has complex and unique physical and chemical properties which can be used to produce magnetic resonance imaging (MRI) contrast. Developing MRI to quantitatively measure myelin is vital for monitoring the brain and spinal cord in health and disease. This thesis explores four MRI techniques sensitive to myelin; myelin water imaging (MWI), magnetisation transfer (MT), inhomogeneous magnetisation transfer (ihMT) and diffusion imaging.
First, these metrics were measured in regions throughout the healthy adult and pediatric brain. Reproducibility, dynamic range and correlations between metrics were investigated. Healthy adult and pediatric atlases of the metrics were made publicly available for other neuroimaging researchers.
Next, the orientation dependence of MWI, MT and ihMT was quantified. White matter is anisotropic, consisting of fiber bundles which vary in angle to the MRI main magnetic field. This can affect MRI metrics through the susceptibility of lipid-rich myelin, anisotropic vasculature, iron content, dipole-dipole and magic angle effects. We found that the orientation dependence curve for each metric varied between brain regions, suggesting that microstructural parameters other than fibre angle are affecting the orientation dependence. Then, we investigated the orientation dependence of ihMT in more detail, using a phospholipid bilayer sample rotated in a nuclear magnetic resonance (NMR) spectrometer to measure the variation with angle of the breadth of the lipid spectrum and dipolar order relaxation time. We found that the lipid linewidth had a greater effect on ihMT than the dipolar order relaxation time under our experimental conditions.
Finally, ex vivo human spinal cord injury (SCI) tissue from the International SCI Biobank was scanned at 7 Tesla to obtain MWI, ihMT and diffusion. This tissue then underwent histological staining for myelin lipids and inflammatory cells. We performed correlations between the MRI metrics and the digitised histological staining to validate the metrics’ specificity to myelin and sensitivity to inflammation processes. We measured the MRI metrics in motor and sensory white matter tracts along the cord, which provided a first glimpse into the possible utility of these techniques as biomarkers to assess the impact of SCI on myelin and axons in vivo.
Event Location:
https://ubc.zoom.us/j/62811600818?pwd=WlJyS09SQ0gva3EwZ1N3dmNDdmZlQT09 Passcode: 459642
Event Time:
Thursday, December 8, 2022 | 4:00 pm - 5:00 pm
Event Location:
HEBB 114
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2022-12-08T16:00:00
2022-12-08T17:00:00
Use of Indigenous Elements in Teaching Mathematics and Science
Event Information:
Abstract:
This presentation is based on materials collected within my research and community-based projects at the First Nations University of Canada and targets three groups of audience: learners, educators and researchers. The materials have been created in three formats: publications, Power Point Presentations and Videos. My intention is to address the importance, doability and advantage of the holistic way of teaching the Science and Mathematics in an example of the integration of modern Science and Indigenous Knowledge elements.
Bio:
Dr. Sardarli joined the First Nations University of Canada in 2007. He led a number of community-based projects. Dr. Sardarli uses Indigenous elements in his teaching. He co-authored the first Cree Dictionary of Mathematical with elements of Indigenous Art. In 2008, Dr. Sardarli initiated a nationwide annual Wiseman Mathematics Contest. He coordinated the research project on mathematical modeling of water quality using Indigenous knowledge. Dr. Sardarli’s projects have been supported by agencies, such as NSERC, SSHRC, Health Canada, and Canadian Heritage. He received The Recognition Event Awards of The Regional Centre of Expertise (Saskatchewan) for his innovative Indigenous community-based projects
Outline:
It is remarkable that the word "Science" that we, educators use as a title for the group of subjects (Physics, Biology, Chemistry, etc.) taught in academia, is translated into many languages (Arabian, Ukrainian, Turkish ...) as "Knowledge", giving the meaning of gaining and analysis of integrated information about both, Nature and Community. This is not just a linguistic nuance. I try to bring elements of the Indigenous Knowledge and Art to the teaching of my post-secondary Mathematics and Science courses in order to add this missing piece to the puzzle, combining the so-called "Western" and Indigenous Knowledge. My view of this integration is very close to the "Etuaptmumk" - Two-Eyed Seeing principle explained by Elder Albert Marshall, which refers to "learning to see from one eye with the strengths of Indigenous knowledge and ways of knowing, and from the other eye with the strengths of Western knowledge and ways of knowing ... and learning to use both these eyes together, for the benefit of all".
In collaboration with my colleagues from the First Nations University of Canada and the University of Regina, I have developed examples with Indigenous elements for Physics, Mathematics and Statistics courses of our universities. Within my research and community-based projects I interviewed Indigenous Elders and Knowledge Keepers in order to collect the information for these examples. The examples are included in the textbooks that I co-authored and course materials offered by the First Nations University of Canada and the University of Regina. These projects were supported by The Natural Sciences and Engineering Research Council of Canada (NSERC), Health Canada, Heritage Canada, First Nations University of Canada and the University of Regina.
Modern technologies allow us to incorporate the original interviews into the teaching materials in various media formats.
Projects:
1. Wiseman Mathematics Contest
I initiated the Wiseman Mathematics Contest was in 2008 at the First Nations University of Canada. The start-up of the project was supported by The Natural Sciences and Engineering Research Council of Canada within the PromoScience program. Since then, thousands of First Nations students from across Canada in grades 4, 5, and 6 across Canada have participated. The purpose of the Contest is to motivate young students in First Nations schools in Saskatchewan and other provinces to learn Mathematics in a competitive environment.
The Wiseman Mathematics Contest meets the needs of Mathematics teachers in First Nations Schools who want to assess their students' problem-solving skills in a competitive environment. Along with the contests, First Nations University also develops and delivers preparatory materials. Mathematics teachers prepare their students for the contest using these materials, but can also use the materials to immerse the students in alternative problem-solving, expanding on curriculum. Many teachers use these materials for extracurricular activities.
Students participate in the project voluntarily. The contest provides the opportunity to work on non-traditional problems in a non-mandatory but competitive environment, which is atypical for Western schools.
In 2016, the Regional Centre of Expertise (Saskatchewan) on Education for Sustainable Development Recognition Program acknowledged the Wiseman Mathematics Contest as an innovative project. It noted that the project has helped increase the capacity for sustainable development in the Saskatchewan region and contributed to the advancement of the UNESCO Global Action Programme on Education for Sustainable Development.
2. Cree Dictionary of Mathematical Terms
In 2015 – 2021, we developed the first explanatory Cree Dictionary of Mathematical Terms in paper (Willie Ermine, Arzu Sardarli, Ida Swan) and online (Arzu Sardarli, Ida Swan) formats. The project was supported by the First Nations University of Canada and the University of Regina. The Dictionary was reviewed by Elders George McLeod and Jerry Saddleback, Indigenous academics Solomon Ratt and Lionel Peyachew, educators Nelson Benjamin Merasty and Steven Swan. The Indigenous artist Larissa Kitchemonia participated in developing visual examples. This project was recognized by Lyle Benko Future Generations Award of the Saskatchewan Regional Centre of Expertise.
Research projects
I used some findings of my research projects to develop examples with Indigenous elements for my university courses.
3. Research project "Developing Mathematical Model of Water Quality Dynamics using Indigenous Knowledge."
This project was conducted in collaboration with the Kahkewistahaw and Peepeekisis First Nations communities. Within the project, we interviewed Indigenous Elders and specified criteria to evaluate the water quality. Community members were asked to evaluate water quality in their communities based on the determined criteria. Using the statistical analysis of the collected data, we developed a mathematical model of the water quality dynamics using the Indigenous way of evaluating the water quality.
4. Research project " Studies of physical parameters of Indigenous artefacts; collecting and preserving the relating oral stories."
This project was conducted by scholars from the First Nations University of Canada, Royal Saskatchewan Museum, University of Regina and University of Saskatchewan in collaboration with Sturgeon Lake and Pelican Narrows First Nations communities in Canada. The objectives of the project were (i) to develop a research ethics protocol for collecting, studying and preserving Indigenous artifacts; (ii) to determine physical parameters of artifacts from communities and Royal Saskatchewan Museum collections; (iii) to collect oral stories in communities. Within the project, we managed consultations with Elders and Indigenous Knowledge Keepers. Two workshops were organized in the communities. Indigenous students were trained to work in the communities. The laboratory measurements were carried out at the Scanning Electron Microscope Laboratory of the University of Alberta, the Saskatchewan Isotope Laboratory of the University of Saskatchewan and the André E. Lalonde Accelerator Mass Spectrometry Laboratory of the University of Ottawa. We analyzed the data obtained from the measurements of physical parameters of artifacts collected in these communities and selected from the Royal Saskatchewan Museum collections. The purpose of the statistical analysis was to determine the similarities of artifacts with respect to their chemical compositions.
REFERENCES:
Books
W. Ermine, A. Sardarli, I. Swan, "Cree Dictionary of Mathematical Terms for Elementary Classes", 170 p, ISBN-13: 978-0-7731-0770-0, University of Regina, 2017
A. Sardarli, I. Swan, "Cree Dictionary of Mathematical Terms with Visual Examples, Online ISBN-13: 978-0-7731-0779-3, University of Regina, 2022
URL: https://opentextbooks.uregina.ca/creemathdictionary/
A. Sardarli, "Studies of Physical Parameters of Indigenous Artifacts. Collecting and preserving the relating oral stories", 160 p, Print ISBN-13: 978-0-7731-0767-0, Online ISBN-13: 978-0-7731-0769-4, University of Regina, 2021
URL: http://indigenous-artifacts.ca/brochure/
A. Sardarli, E. Siegfried, S. Wall, “Studies of Physical Parameters of Indigenous Artifacts. Collecting and preserving the relating oral stories. Catalogue”, 86 p, Print ISBN-13: 978-0-7731-0765-6, Online ISBN-13: 978-0-7731-0766-3, University of Regina, 2021
URL: http://indigenous-artifacts.ca/catalogue/
Articles
"Two-Eyed Seeing", Mi'kmaw Elder Albert Marshall
URL: http://www.integrativescience.ca/Principles/TwoEyedSeeing/
A. Sardarli, Use of Indigenous Knowledge in Modeling the Water Quality Dynamics in Peepeekisis and Kahkewistahaw First Nations Communities, Pimatiswin: A Journal of Aboriginal and Indigenous Community Health 11(1), 2013, 55-63
URL: https://journalindigenouswellbeing.co.nz/use-of-indigenous-knowledge-in-modeling-the-water-quality-dynamics-in-peepeekisis-and-kahkewistahaw-first-nations-communities/
A. Sardarli, S. Pete, T. Ngamkham, S. Suraphee, A. Volodin, The Determinants of Annual Income in Aboriginal and Non-Aboriginal Communities: Comparative Statistical Analysis, Thailand Statistician, 17(2), 2019, 235-241
URL: https://ph02.tci-thaijo.org/index.php/thaistat/article/view/202300/141174
A. Sardarli, A. Volodin, Kh. Osmanli, E. Siegfried, Statistical Analysis of Physical Parameters of Indigenous Artifacts, Lobachevskii Journal of Mathematics, 42 (13), 2021, 3224-3229
URL: https://link.springer.com/article/10.1134/S1995080222010188
Project Websites
Wiseman Mathematics Contest | URL: https://www.facebook.com/WisemanContest
Studies of Physical Parameters of Indigenous Artifacts. Collecting and preserving the relating oral stories | URL: http://indigenous-artifacts.ca/
Event Location:
HEBB 114
Event Time:
Monday, December 5, 2022 | 3:00 pm - 4:00 pm
Event Location:
HENN 318
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2022-12-05T15:00:00
2022-12-05T16:00:00
A Revolution in Stellar Astrophysics, and the Remaining Challenges
Event Information:
Abstract:
ESA's Gaia mission has provided distances to around 1.5 billion stars and revolutionized stellar astrophysics. Gaia has finally revealed the population
of faint white dwarf stars in the solar neighborhood. We use this dataset to answer fundamental questions about the nature of white dwarfs, including their
mass distribution, cooling physics (crystallization), and ultracool white dwarfs. I will highlight the current challenges in the physics of white dwarf stars and
our efforts to solve them.
Bio:
Mukremin Kilic is an associate professor in the Department of Physics & Astronomy at the University of Oklahoma.
Event Location:
HENN 318