Events List for the Academic Year
Event Time:
Thursday, November 26, 2020 | 2:00 pm - 3:00 pm
Event Location:
Zoom https://ubc.zoom.us/j/65784122083?pwd=U09vVXJMRzNLaTY3bmVXNEFJZ1k3UT09
Meeting code: 657 8412 2083
Passcode: 113399
Meeting code: 657 8412 2083
Passcode: 113399
Add to Calendar
2020-11-26T14:00:00
2020-11-26T15:00:00
CM Seminar - Magnetoelectric generation of a Majorana-Fermi surface in Kitaev's honeycomb model
Event Information:
Title: "Magnetoelectric generation of a Majorana-Fermi surface in Kitaev's honeycomb model"
Abstract: "Recently, Kitaev materials have attracted great interest due to their potential to realize a quantum spin liquid ground state which hosts gapless Majorana excitations. In this talk, after a review of the physics of Kitaev materials, I will discuss the effects of static magnetic and electric fields on Kitaev's honeycomb model. Using the electric polarization operator appropriate for Kitaev materials, I will derive the effective Hamiltonian for the emergent Majorana fermions to second-order in both the electric and magnetic fields. While individually each perturbation does not qualitatively alter Kitaev spin liquid, the magneto-electric cross-term induces a finite chemical potential at each Dirac node, generating a Majorana-Fermi surface. I will argue this gapless phase is stable and exhibits typical metallic phenomenology, such as linear in temperature heat capacity and finite, but non-quantized, thermal Hall response. Finally, I will discuss the potential for realization of this, and related, physics in Kitaev materials such as RuCl3."
Bio: "Jeffrey G. Rau is an assistant professor at the University of Windsor working in the field of theoretical condensed matter physics. He received his Ph.D. from the University of Toronto followed by post-doctoral work at the University of Waterloo and the Max Planck Institute for the Physics of Complex Systems in Dresden. His research broadly falls under the heading of quantum magnetism, with a focus on highly frustrated systems with strong anisotropy."
Event Location:
Zoom https://ubc.zoom.us/j/65784122083?pwd=U09vVXJMRzNLaTY3bmVXNEFJZ1k3UT09
Meeting code: 657 8412 2083
Passcode: 113399
Event Time:
Wednesday, November 25, 2020 | 11:00 am - 12:00 pm
Event Location:
Connect via Zoom
Add to Calendar
2020-11-25T11:00:00
2020-11-25T12:00:00
Renormalizable QFT for gravity
Event Information:
I will start with a review of how General Relativity can be treated as a quantum field theory, as well as some of its limitations. After a general discussion of the Arrow of Causality in QFT, I will turn to gravity with quadratic curvature terms, which is a potential UV completion of General Relativity. This forms a renormalizable QFT, although it is one with some non-standard features. The talk will try to walk us all through some of what is known about these non-standard aspects.
Event Location:
Connect via Zoom
Event Time:
Monday, November 23, 2020 | 3:00 pm - 4:00 pm
Event Location:
Connect via zoom
Add to Calendar
2020-11-23T15:00:00
2020-11-23T16:00:00
Baryonic effects on cosmological large scale structure
Event Information:
Upcoming measurements of large-scale clustering in the universe promise to provide new insights into cosmology and fundamental physics, but a variety of modelling and analysis challenges must be addressed if this promise is to be fully realized. In this talk, I will discuss one such challenge: the modelling uncertainty associated with so-called "baryonic effects," specifically the influence of gas dynamics and feedback from active galactic nuclei on the large-scale distribution of matter. After reviewing the broad picture of these effects provided by hydrodynamical simulations, I will present case studies of their impact on (1) neutrino mass measurements using gravitational lensing of the cosmic microwave background, and (2) generic three-point clustering statistics. I also briefly review different observational avenues for constraining these effects, which will likely play an important role in the success of upcoming cosmological surveys.
Event Location:
Connect via zoom
Event Time:
Thursday, November 19, 2020 | 4:00 pm - 5:00 pm
Event Location:
Connect via zoom
Add to Calendar
2020-11-19T16:00:00
2020-11-19T17:00:00
Wave Energy Testing Off Point Grey, UBC: 10 Year Report
Event Information:
Experimental research in a full-size wave energy system has been conducted over the past 10 years with 6 deployments to solve the problem of producing continuous electrical power for at least 8,000 hours per year from energy dense water waves.
Globally, wave energy is available to 150 of the 201 countries (75%) provided near shore, low height (avg. 1.5 m) waves can be utilized. The main advantages of Wave energy compared to Solar and Wind are: high energy density per sq. m. hence a tiny area (approx. 6% of Solar & 0.4% of Wind area) is required to produce the same amount of energy; Waves provide a continuous-variable energy input while Solar & Wind provide an intermittent-variable input; and wave devices enhance the sub-sea as well as the above sea environments for birds and marine organisms. The Investigative Use Foreshore Land Contract and recent discussions with BC Hydro will be mentioned.
The 8 wave energy device types with examples of each and comments why they are not being pursued, and a very brief history of the 10 years of device experiments and lessons learned leading up to the final working prototype used in the Vancouver Wave Energy Testing Station will be shown.
A general discussion of some problems encountered: in transferring wave energy formula theory (linear wave & fluid mechanics) to a practical application; the problem of using the “Significant Wave Height” metric (which was created for marine shipping safety), and the solution we have ended up with: simply measure the power and energy obtained. The results of our tank, calculation model, shop tests & the ongoing field tests in the Vancouver Wave Energy Test Station ocean testbed will be shown.
Future: plans for a 1 MW plus wave engine with multi pistons added-on to Wind Turbine mono poles used for continuous electricity, water desalination & hydrogen electrolysis to usher in the beginning of the wave energy industry will be shown with a scatter chart of projected power generated based on experimental verifiable evidence.
Event Location:
Connect via zoom
Event Time:
Thursday, November 19, 2020 | 2:00 pm - 3:00 pm
Event Location:
https://ubc.zoom.us/j/65784122083?pwd=U09vVXJMRzNLaTY3bmVXNEFJZ1k3UT09
Passcode: 113399
Passcode: 113399
Add to Calendar
2020-11-19T14:00:00
2020-11-19T15:00:00
CM Seminar - measuring current-phase relations in exotic Josephson junctions
Event Information:
Abstract: Theorists have proposed various exotic Josephson junctions both for fundamental demonstrations of exotic behaviors and as highly desirable platforms for qubits. The supercurrent, I, versus the phase, ϕ, across the junction is called the current-phase relation (CPR) and reveals fundamental properties of the junction. Using a scanning SQUID, we measure the CPR of individual Josephson junctions. In InAs nanowire Josephson junctions, we find skewed CPRs with small critical currents, indicating few-mode junctions with high transmissions. In gate-tunable junctions, we found that the CPR varied with gate voltage: Near the onset of supercurrent, we observed behavior consistent with resonant tunneling through a single, highly transmitting mode. The gate dependence is consistent with modeled subband structure that includes an effective tunneling barrier due to an abrupt change in the Fermi level at the boundary of the gate-tuned region. These measurements of skewed, tunable, few-mode CPRs are promising both for applications that require anharmonic junctions and for Majorana readout proposals.
Bio: Kathryn A."Kam" Moler is the Vice Provost and Dean of Research, the Marvin Chodorow Professor, and Professor of Applied Physics and of Physics at Stanford University. She conducts research in magnetic imaging, develops tools that measure nanoscale magnetic fields, and studies quantum materials and devices. Among other honors, she received a national Presidential Early Career Award for Scientists and Engineers, held a Packard Fellowship for Science and Engineering, received the William L. McMillan Award “for her fundamental studies of the superconducting pairing state, Josephson vortices, and the role of interlayer coupling in high-temperature superconductors,” and was elected a Fellow of the American Physical Society. To honor her sustained commitment to teaching, the American Association of Physics Teachers awarded her the Richtmyer Award for Outstanding Leadership in Physics Education, and Stanford appointed her as the Sapp Family Fellow in Undergraduate Education. She was previously the Senior Associate Dean of Natural Sciences in the School of Humanities and Sciences and the Director of the Stanford Nano Shared Facilities. She is a member of the NanoFront (TU-Delft/Leiden) Scientific Advisory Board and the Physics Frontier Center—Joint Quantum Institute Advisory Board.
Event Location:
https://ubc.zoom.us/j/65784122083?pwd=U09vVXJMRzNLaTY3bmVXNEFJZ1k3UT09
Passcode: 113399
Event Time:
Monday, November 16, 2020 | 3:00 pm - 4:00 pm
Event Location:
Connect via zoom
Add to Calendar
2020-11-16T15:00:00
2020-11-16T16:00:00
Merging Galaxies & Supermassive Black Hole Binaries: Multi-Messenger Astrophysics with Pulsar Timing Arrays
Event Information:
Pulsar timing arrays (PTAs) are galactic-scale low-frequency (nHz - μHz) gravitational wave (GW) observatories, which aim to directly detect GWs from supermassive black hole (SMBH) binaries (≥ 107 M⊙). SMBH binaries are predicted products of galaxy mergers and are a crucial step in galaxy formation theories. The primary source of gravitational radiation in the nHz regime is expected to be a stochastic background formed from the cosmic population of SMBH binaries. In this talk, I will discuss the current state-of-the-art detection approaches to searching for a gravitational wave background in pulsar timing data, including a novel approach to account for errors in Solar System ephemerides, and present the results obtained by analyzing the newest data release from the North American Observatory for Gravitational Waves (NANOGrav). Our analysis shows a strong preference for a stochastic process with a common spectrum in all pulsars. However, the evidence is only slightly higher for a spatially correlated process. Spatial correlations are considered the "smoking gun" of gravitational wave background detection, thus the analysis of this data set remains inconclusive. Assuming the signal is indeed an astrophysical background, I will end my talk with a discussion of the expected growth in future data sets, as well as the astrophysics we expect to constrain in the coming years.
Event Location:
Connect via zoom
Event Time:
Thursday, November 12, 2020 | 4:00 pm - 5:00 pm
Event Location:
Connect via zoom
Add to Calendar
2020-11-12T16:00:00
2020-11-12T17:00:00
Quantum Materials by Design @ UBC-QMI
Event Information:
In most materials, electrons move around and scatter essentially independently of one another. In quantum materials, in contrast, electrons engage in highly correlated motions that resemble a complex dance. These correlations give rise to a wide range of astonishing electronic and magnetic properties that evoke the most profound scientific questions challenging the field of condensed matter physics.
Research at the Stewart Blusson Quantum Matter Institute (QMI) seeks to unravel and exploit the complex phenomena that emerge in novel engineered materials — not only as a result of these strong electronic correlations, but also from other sources of extraordinary behavior, such as topological states or physical structures created artificially at the atomic scale. Our research has advanced beyond merely exploring these materials so we can now begin to rationally design materials with the ideal properties to serve as building blocks for future ultra-high-performance technologies; synthesize these materials; characterize them, developing new experimental and theoretical techniques along the way as needed; and using them to fabricate archetype devices to demonstrate their technological potential.
In this talk, I will provide an overview of the Quantum Materials and Future Technologies program at QMI, funded in 2015 by the Canada First Research Excellence Fund. With unique activities such as the launch of our research Grand Challenges, the development of the Quantum Pathways education initiative, and the creation of industry consortia, QMI brings together research, training, and translation in one holistic coherent effort in quantum materials & quantum technologies.
Event Location:
Connect via zoom
Event Time:
Thursday, November 12, 2020 | 2:00 pm - 3:00 pm
Event Location:
https://ubc.zoom.us/j/65784122083?pwd=U09vVXJMRzNLaTY3bmVXNEFJZ1k3UT09
Meeting ID: 657 8412 2083
Passcode: 113399
Meeting ID: 657 8412 2083
Passcode: 113399
Add to Calendar
2020-11-12T14:00:00
2020-11-12T15:00:00
CM Seminar - Designing, Synthesizing, and Characterizing Novel Quantum Magnets:
Event Information:
Abstract: Just as the discovery of semiconductors revolutionized the electronic industry in the twentieth century, Quantum Materials hold the key to advanced technological properties. There is much basic scientific research still necessary to unveil the tantalizing potential of Quantum Materials. To that end, my research program is focused on advancing our ability to design, synthesize and characterize Quantum Materials, in particular Quantum Magnets. This talk will be focused on two main topics: (1) Our efforts to study the properties of a specific class of Quantum Magnets, the so-called Rare-Earth-based “Quantum Spin Liquid” (QSL) candidates. In QSLs the spins of the constituent electrons are predicted to become strongly entangled and fail to form a static ordered state as in a conventional magnet. (2) Our work to investigate the underlying properties of a recently discovered class of Quantum Magnets, the so-called “Topological Magnon Insulators (TMI),” and to develop a recipe to design and synthesis the perfect TMI candidates, while advancing experimental techniques to probe their topological nature directly and unambiguously.
Bio: Sara Haravifard is a William M. Fairbank Assistant Professor of Physics and Assistant Professor of Mechanical Engineering and Materials Science at Duke University. She received her B.Sc., M.Sc. and Ph.D. from McMaster University in Canada. She conducted her graduate research work under the supervision of Prof. Bruce Gaulin, focusing on the neutron scattering studies of singlet ground state quantum magnets. Following her graduation, she spent three years as postdoctoral associate at the University of Chicago and Argonne National Laboratory – working jointly with Prof. Thomas Rosenbaum and Dr. George Srajer. Following her postdoctoral appointment, she was promoted as an Assistant Physicist at the Argonne National Laboratory. During this time her research centered on performing transport techniques as well as Xray and neutron scattering studies of quantum magnets under extreme sample environments of high-pressures, high-magnetic fields and ultra-low temperatures. In July 2015, Sara joined Duke university as an assistant professor of physics and the William M. Fairbank chair in experimental condensed matter. She joined the department of Mechanical Engineering and Materials Science in 2017, and in 2018 she was awarded the honorary title of associate of Duke Initiative for Science & Society. Her current research aims to develop a deeper understanding of geometrically frustrated quantum materials, especially those exhibiting quantum phase transitions as a function of chemical doping, pressure, and magnetic field.
Event Location:
https://ubc.zoom.us/j/65784122083?pwd=U09vVXJMRzNLaTY3bmVXNEFJZ1k3UT09
Meeting ID: 657 8412 2083
Passcode: 113399
Event Time:
Monday, November 9, 2020 | 3:00 pm - 4:00 pm
Event Location:
Connect via zoom
Add to Calendar
2020-11-09T15:00:00
2020-11-09T16:00:00
Planetesimals in the Kuiper Belt
Event Information:
Kuiper Belt Objects (KBOs), in the outer Solar System, provide a unique laboratory for studying the formation of small bodies. I will summarize our state of understanding of planetesimal formation in the Kuiper Belt as informed by: the size distribution of KBOs as measured through reflected optical light and occultations; the dynamical stability of Kuiper Belt binaries; the orbital stability of the classical Kuiper Belt; and the imaging returned from the New Horizons mission. These lines of evidence provide compelling evidence for a streaming instability process as the trigger of planetesimal formation, but there are details that remain discordant.
Event Location:
Connect via zoom
Event Time:
Thursday, November 5, 2020 | 4:00 pm - 5:00 pm
Event Location:
Connect via zoom
Add to Calendar
2020-11-05T16:00:00
2020-11-05T17:00:00
On Growth, Success and Well-being in Academia
Event Information:
Abstract:
"Good is the enemy of great." There are bad, good and great ways of being an academic scientist and faculty member. In this talk, we aim to provide some perspectives and insights on growth, success and well-being in the academic context. It is important for trainees and junior faculty members to be well informed of what may lie ahead in the academic world, and for all of us to share information, experience and perspectives on how to navigate successful and satisfying careers.
Objectives:
1) To discuss challenges, opportunities, and subtleties within academia.
2) To discuss the importance of seeking mentorship and putting oneself in the company of balanced high-achievers.
3) To discuss an array of ideas towards more effective, successful publications, grants, lab/team formation, training, etc.
Event Location:
Connect via zoom
Event Time:
Thursday, November 5, 2020 | 2:00 pm - 3:00 pm
Event Location:
https://ubc.zoom.us/j/65784122083?pwd=U09vVXJMRzNLaTY3bmVXNEFJZ1k3UT09
Meeting ID: 657 8412 2083
Passcode: 113399
Meeting ID: 657 8412 2083
Passcode: 113399
Add to Calendar
2020-11-05T14:00:00
2020-11-05T15:00:00
CM Seminar - Microscopic evidence for a chiral superconducting order parameter in the heavy fermion superconductor UTe2
Event Information:
Abstract: Topological superconductors represent a fundamentally new phase of matter. Similar to topological insulators, the non-trivial topological characteristics of a topological superconductor dictate the presence of a topological edge states composed of Bogoliubov quasiparticles which live inside and span the superconducting gap. The intense interest in these materials stems from the fact that Bogoliubov excitations inside the gap of a topological superconductor are predicted to have all the characteristics of Majorana Fermions. A chiral p-wave superconductor which is topologically non-trivial is a natural platform for realizing these Majorana modes. In this talk I present scanning tunneling microscopy (STM) data on the newly discovered heavy fermion superconductor, UTe2 with a TC of 1.6K. I will show signatures of coexisting Kondo effect and superconductivity which show competing spatial modulations within one unit-cell. STM spectroscopy at step edges show signatures of chiral in-gap states, predicted to exist at the boundaries of a topological superconductor. Combined with existing data indicating triplet pairing, the presence of chiral edge states suggests that UTe2 is a strong candidate material for chiral-triplet topological superconductivity.
Event Location:
https://ubc.zoom.us/j/65784122083?pwd=U09vVXJMRzNLaTY3bmVXNEFJZ1k3UT09
Meeting ID: 657 8412 2083
Passcode: 113399
Event Time:
Tuesday, November 3, 2020 | 11:00 am - 12:00 pm
Event Location:
ZOOM - https://ubc.zoom.us/j/66656386980?pwd=QnV0WkJrVHpGNnNqRXE5U21tMUlLUT09, Passcode: 243095
Add to Calendar
2020-11-03T11:00:00
2020-11-03T12:00:00
Single-molecule microscopy platform for therapeutics research and development: the next level of resolution
Event Information:
Molecular interactions lie at the core of biochemistry and biology, and their understanding is crucial to the advancement of biotechnology, therapeutics, and diagnostics. Most existing tools make “ensemble” measurements and report a single result, typically averaged over millions of molecules or more. These measurements can miss rare events, averaging out the natural variations or sub-populations within biological samples, and consequently obscure insights into multi-step and multi-state reactions. The ability to make robust and quantitative measurements on single molecules, cellular complexes and cells is a critical unmet need. In this talk, I will introduce a general method called “CLiC” imaging to image molecular interactions one molecule at time with precision and control, without tethers, and under cell-like conditions. CLiC works by mechanically confining molecules to the field of view in an optical microscope, isolating them in nanofabricated features, and eliminates the complexity and potential biases inherent to tethering molecules. By directly imaging the trajectories of many single molecules simultaneously and in a dynamic manner, CLiC allows us to investigate and discover the design rules and mechanisms which govern how therapeutic molecules (or molecular probes) interact with target sites on nucleic acids, and how molecular cargo is released inside cells from lipid nanoparticles. In the outlook of this talk, I will discuss applications of our single-molecule platform to help develop and understand emerging classes of genetic medicines as well as gene editing and drug delivery systems, and highlight applications to connect our observations from the level of single molecule to single cells.
Event Location:
ZOOM - https://ubc.zoom.us/j/66656386980?pwd=QnV0WkJrVHpGNnNqRXE5U21tMUlLUT09, Passcode: 243095
Event Time:
Monday, November 2, 2020 | 3:00 pm - 4:00 pm
Event Location:
Connect via zoom
Add to Calendar
2020-11-02T15:00:00
2020-11-02T16:00:00
Binary star evolution: a multi-wavelength, multi-messenger puzzle
Event Information:
Recent observations of binary black hole and binary neutron star mergers have ignited interest in the formation and evolution of compact-object binary systems. However, by the time a compact-object binary merges and produces gravitational-wave/electromagnetic signals that we can observe, much of the evolutionary history of the stellar progenitors is washed away. By combining binary population synthesis simulations with observations, we can work to constrain the uncertain processes that govern the evolution of binary stars, from zero age main sequence through to compact object formation. In this talk I will introduce a community-developed population synthesis code: COSMIC and highlight some recent work which explores how to combine binary population simulations with future data from gravitational wave and electromagnetic surveys to constrain the formation and evolution of compact-object binaries across the HR Diagram.
Event Location:
Connect via zoom
Event Time:
Friday, October 30, 2020 | 9:00 am - 11:00 am
Event Location:
via Zoom
Add to Calendar
2020-10-30T09:00:00
2020-10-30T11:00:00
"Adaptive Radiotherapy Treatment Corrections to Account for Patient-Specific Systematic Soft Tissue Deformations: Prostate, Lung, and Head & Neck Cancer”
Event Information:
Departmental Doctoral Oral Examination
Abstract: (see this link)
Event Location:
via Zoom
Event Time:
Thursday, October 29, 2020 | 4:00 pm - 5:00 pm
Event Location:
Connect via zoom
Add to Calendar
2020-10-29T16:00:00
2020-10-29T17:00:00
Supermassive Black Holes as Revealed by LISA: How Gravitational Wave Astronomy Will be a Game Changer
Event Information:
Astronomers now know that supermassive black holes are in nearly every galaxy. Though these black holes are an observational certainty, nearly every aspect of their evolution - from their birth, to their fuel source, to their basic dynamics - is a matter of lively debate. Fortunately, LISA, a space-based gravitational wave observatory set to launch in 2034, will revolutionize this field by providing data that is complementary to electromagnetic observations, as well as data in regimes that are electromagnetically dark. This talk will touch on our current understanding of how SMBHs form, evolve, and alter their galaxy host, and will outline the theoretical, computational and observational work needed to make the most of LISA observations.
Event Location:
Connect via zoom
Event Time:
Thursday, October 29, 2020 | 2:00 pm - 3:00 pm
Event Location:
https://ubc.zoom.us/j/65784122083?pwd=U09vVXJMRzNLaTY3bmVXNEFJZ1k3UT09
Meeting ID: 657 8412 2083
Passcode: 113399
Meeting ID: 657 8412 2083
Passcode: 113399
Add to Calendar
2020-10-29T14:00:00
2020-10-29T15:00:00
CM Seminar : Quantum supremacy using a programmable superconducting processor
Event Information:
Abstract: The promise of quantum computers is that certain computational tasks might be executed exponentially faster on a quantum processor than on a classical processor. A fundamental challenge is to build a high-fidelity processor capable of running quantum algorithms in an exponentially large computational space. Here we report the use of a processor with programmable superconducting qubits to create quantum states on 53 qubits, corresponding to a computational state-space of dimension 2^53 (about 10^16).
Measurements from repeated experiments sample the resulting probability distribution, which we verify using classical simulations. The Google Sycamore processor takes about 200 seconds to sample one instance of a quantum circuit a million times—our benchmarks currently indicate that the equivalent task for a state-of-the-art classical supercomputer would take approximately 10,000 years. This dramatic increase in speed compared to all known classical algorithms is an experimental realization of quantum supremacy for this specific computational task, heralding a much-anticipated computing paradigm.
Biography: John Martinis did pioneering experiments in superconducting qubits in the mid 1980’s for his PhD thesis. He has worked on a variety of low temperature device physics during his career, focusing on quantum computation since the late 1990s. He was awarded the London Prize in Low temperature physics in 2014 for his work in this field. From 2014 to 2020 he worked at Google to build a useful quantum computer, culminating in a quantum supremacy experiment in 2019.
Event Location:
https://ubc.zoom.us/j/65784122083?pwd=U09vVXJMRzNLaTY3bmVXNEFJZ1k3UT09
Meeting ID: 657 8412 2083
Passcode: 113399
Event Time:
Wednesday, October 28, 2020 | 2:00 pm - 4:00 pm
Event Location:
via Zoom
Add to Calendar
2020-10-28T14:00:00
2020-10-28T16:00:00
“Reductions in finite-dimensional quantum mechanics: from symmetries to operator algebras and beyond”
Event Information:
Departmental Doctoral Oral Examination
Abstract:
The idea that symmetries simplify or reduce the complexity of a system has been remarkably fruitful in physics, and especially in quantum mechanics. On a mathematical level, symmetry groups single out a certain structure in the Hilbert space that leads to a reduction. This structure is given by the irreducible representations of the group, and in general it can be identified with an operator algebra (a.k.a. C*-algebra or von Neumann algebra). The primary focus of this thesis is the extension of the framework of reductions from symmetries to operator algebras, and its applications in finite-dimensional quantum mechanics.
One of the main technical results that we present is the Scattering Algorithm for analytical derivations of the irreducible representations structure of operator algebras. For applications, we will introduce a symmetry-agnostic approach to the reduction of dynamics where we circumvent the non-trivial task of identifying symmetries, and directly reduce the dynamics generated by a Hamiltonian. We will also consider quantum state reductions that arise from operational constraints, such as the partial trace or the twirl map, and study how operational constraints lead to decoherence. Apart from our primary focus we will extend the idea of reduction beyond operator algebras to operator systems, and formulate a quantum notion of coarse-graining that so far only existed in classical probability theory.
Event Location:
via Zoom
Event Time:
Monday, October 26, 2020 | 3:00 pm - 4:00 pm
Event Location:
Connect via zoom
Add to Calendar
2020-10-26T15:00:00
2020-10-26T16:00:00
A Holistic View of Exoplanets, their Environments, and their Potential to Host Life
Event Information:
Roughly seventy-five billion low-mass stars (a.k.a. M dwarfs) in our galaxy host at least one small planet in the habitable zone (HZ), where surface life might exist. The stellar ultraviolet (UV) radiation from M dwarfs is strong and highly variable, and their planets are exposed to "superflares" daily in their first ~300 Myr. Knowing the UV environments of planets of all sizes is crucial to understand their atmospheric composition and evolution, and provides the needed context for measured exoplanet spectra at all wavelengths. For HZ terrestrial planets, characterization of the UV provides a key parameter in a planet's potential to be habitable and helps us to discriminate between biological and abiotic sources for observed biosignatures. Our efforts to study the UV exoplanet environments photometrically and spectroscopically employ past, present and future space telescopes: GALEX, HST, the upcoming SPARCS cubesat, and the new MidEx-mission concept UV-SCOPE (Ultraviolet Spectroscopic Characterization Of Planets and their Environments). In addition to the study of host stars, UV-SCOPE will be a dedicated telescope to measure UV transmission spectra of exoplanets. It will probe the conditions and composition of their upper-atmospheres, directly measure exospheric escape, and derive the associated impact of stellar UV radiation upon planets.
Event Location:
Connect via zoom
Event Time:
Thursday, October 22, 2020 | 4:00 pm - 5:00 pm
Event Location:
Connect via zoom
Add to Calendar
2020-10-22T16:00:00
2020-10-22T17:00:00
Low rattling: a principle for understanding driven many-body self-organization
Event Information:
Self-organization is frequently observed in active collectives, from ant rafts to molecular motor assemblies. General principles describing self-organization away from equilibrium have been challenging to identify. We offer a unifying framework that models the behavior of complex systems as largely random, while capturing their driven response properties. Such a "low-rattling principle" enables prediction and control of fine-tuned emergent properties in disordered mechanical networks, random spin glasses, and robot swarms.
Event Location:
Connect via zoom
Event Time:
Thursday, October 22, 2020 | 2:00 pm - 3:00 pm
Event Location:
https://ubc.zoom.us/j/65784122083?pwd=U09vVXJMRzNLaTY3bmVXNEFJZ1k3UT09
Meeting ID: 657 8412 2083
Passcode: 113399
Meeting ID: 657 8412 2083
Passcode: 113399
Add to Calendar
2020-10-22T14:00:00
2020-10-22T15:00:00
CM Seminar - Doping a Mott Insulator and Unconventional Superconductivity in a Triangular Adatom Layer on a Silicon Surface
Event Information:
Abstract: The physics of doped Mott insulators is at the heart of some of the most exotic physical phenomena in materials research. The adsorption of a one-third monolayer of Sn atoms on a Si(111) surface produces a triangular surface lattice with half-filled dangling bond orbitals. In this talk, I will show how modulation hole doping of these dangling bonds unveils clear hallmarks of Mott physics [1], including a spectral weight transfer and the formation of dispersive quasiparticles at the Fermi level. I will also discuss the recent observation of superconductivity [2] in the most heavily hole-doped monolayers and evidence for an unconventional d+id chiral order parameter. These observations are remarkably similar to those made in complex oxide materials, including high-temperature superconductors, but highly extraordinary within the realm of conventional sp-bonded semiconductor materials.
Event Location:
https://ubc.zoom.us/j/65784122083?pwd=U09vVXJMRzNLaTY3bmVXNEFJZ1k3UT09
Meeting ID: 657 8412 2083
Passcode: 113399