Events List for the Academic Year

Event Time: Monday, April 8, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
Add to Calendar 2024-04-08T16:00:00 2024-04-08T17:00:00 Pushing the frontiers of galaxy formation modeling with multi-scale simulations and machine learning Event Information: Abstract: Supermassive black holes (SMBHs) in Active Galactic Nuclei (AGN) play a key role in the formation of galaxies and large-scale structure, but the triggering and impact of AGN feedback across scales and the origin of the observed SMBH–galaxy connection remain major open questions owing to the multi-scale and multi-physics nature of the problem. AGN feedback can also profoundly affect the properties and spatial distribution of baryons on scales that contain a large amount of cosmological information.  Current and upcoming cosmological surveys will provide unprecedented data to constrain the fundamental cosmological parameters, but uncertainties in galaxy formation physics remain a major theoretical obstacle to extract information from cosmological experiments.  In this talk, I will present new simulation techniques that are pushing the frontiers of galaxy formation modeling towards (1) the smallest scales, developing physically predictive models of SMBH accretion and feedback explicitly at sub-pc resolution in a full cosmological context to interpret a plethora of galaxy and AGN observables, and (2) the largest scales, developing thousands of large-volume simulations exploring a wide range of sub-grid feedback implementations to train robust machine learning algorithms that can maximize the extraction of information from cosmological surveys while marginalizing over uncertainties in galaxy formation physics.  I will demonstrate the feasibility of these orthogonal approaches to address fundamental problems and discuss their potential to significantly advance the fields of galaxy evolution and cosmology. Bio: Dr. Daniel Anglés-Alcázar is an Assistant Professor of Physics at the University of Connecticut, specializing in Computational Galaxy Formation.    Learn More: See his research group website here Read more about his research interests here     Event Location: HENN 318
Event Time: Thursday, March 21, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 202
Add to Calendar 2024-03-21T16:00:00 2024-03-21T17:00:00 Making and measuring macromolecular machines Event Information: Abstract :Molecular machines lie at the heart of biological processes ranging from DNA replication to cell migration. We use single-molecule tracking and manipulation to characterize the structural dynamics of these nanoscale assemblies, and further challenge our understanding by designing and testing structural variants with novel properties that expand the functional range of known biomolecular machines. In the process, we are developing an engineering capacity for molecular motors with tunable and dynamically controllable physical properties, providing a toolkit for precise perturbations of mechanical functions. We have previously developed a family of light-responsive myosin motors, enabling precise control of fast and processive molecular transport in vitro and in living cells. I will describe our ongoing efforts to augment and diversify engineered cytoskeletal motors, including newly developed light-responsive filamentous myosins for control of contractility. I will further discuss our measurements of dynamics and mechanics in CRISPR endonucleases. In the latter work, we have used high-resolution multimodal single-molecule methods to study the process of DNA interrogation by Cas9 and Cas12a.  We have observed intermediate steps in target recognition and probed important effects of DNA torsion on the dynamics and specificity of these nucleoprotein machines.   Bio: Zev Bryant is an Associate Professor of Bioengineering and Structural Biology at Stanford University.  Molecular motors lie at the heart of biological processes from DNA replication to vesicle transport. My laboratory seeks to understand the physical mechanisms by which these nanoscale machines convert chemical energy into mechanical work. We use single molecule tracking and manipulation techniques to observe and perturb substeps in the mechanochemical cycles of individual motors. Protein engineering helps us to explore relationships between molecular structures and mechanical functions. Broad topics of current interest include torque generation by DNA-associated ATPases and mechanical adaptations of unconventional myosins. B.Sc., University of Washington, Biochemistry (1998)Ph.D., UC, Berkeley, Molecular and Cell Biology (2003) Predoctoral Fellowship, Howard Hughes Medical Institute (1999)Harold M. Weintraub Award, FHCRC (2004)Alan Bearden Award, UC, Berkeley (2004)Postdoctoral Fellowship, Helen Hay Whitney Foundation (2005)Director's New Innovator Award, NIH (2008)Pew Scholars Award, Pew Charitable Trusts (2009)   Learn More: Read his Stanford University profile page here See his Stanford Engineering page here   Event Location: HENN 202
Event Time: Thursday, March 21, 2024 | 10:00 am - 11:00 am
Event Location:
BRIM 311
Add to Calendar 2024-03-21T10:00:00 2024-03-21T11:00:00 Equilibrium and far-from-equilibrium properties of bipolaron coupled to dispersive phonons Event Information: Abstract: In the first part of my talk, I will discuss  a Holstein-like model with two electrons nonlinearly coupled to quantum phonons. Using an efficient method based on full quantum approach [1-4] we  simulate the dynamical response of a system subject to a short spatially uniform optical pulse that couples to dipole-active vibrational modes. Nonlinear electron-phonon coupling can either soften or strengthen the phonon frequency in the presence of electron density [5]. When two electrons are free to propagate on a lattice subject to non-linear coupling to phonons that soften phonon frequency, an external optical pulse with well tuned frequency can induce attraction between electrons. Electrons remain bound long after the optical pulse is switched off. Changing the frequency of the pulse the attractive electron–electron interaction can be switched to repulsive. Two sequential optical pulses with different frequencies can switch between attractive and repulsive interaction [6]. In the second part, I will discuss the phase diagram of the bipolaron in the Holstein – Hubbard model in the presence of dispersive phonons. We show that a finite dispersion can stabilize a bound bipolaron even at large Coulomb repulsion U [7]. The sign of the curvature of the optical phonon dispersion plays a decisive role on the bipolaron binding energy and the effective mass in the presence of  U. Finally, I will discuss the influence of U on the ARPES spectral function of the bipolaron. Speaker Bio: Janez Bonca is a Professor and Dean of the Faculty of Mathematics and Physics at the University of Ljubljana, Slovenia. His research interests include theory of incommensurate systems, theory of strongly correlated systems and high temperature superconductors, theory of heavy fermion systems, theory of mesoscopic systems and quantum dots, theory of frustrated spin systems, physics of electron – phonon interaction and theory of polarons and bipolarons, study of systems driven far from equilibrium, thermalization in many-body systems, theory of many-body localization. Prof. Bonca completed his PhD from the University of Ljubljana, and worked as a Post-doctoral Associate at  Los Alamos National Laboratory from 1992-1995. Event Location: BRIM 311
Event Time: Monday, March 18, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
Add to Calendar 2024-03-18T16:00:00 2024-03-18T17:00:00 Emerging Views of the Kuiper Belt from JWST Event Information: Abstract: The Kuiper Belt (also called Trans-Neptunian region) is a large population of sub-planet-sized beyond the orbit of Neptune.  These bodies provide windows into conditions of the outer solar nebula, the process of planet growth and differentiation in icy bodies, and current dynamics and dynamical evolution of the Solar System.  Mapping of their orbits has revealed distinct dynamical structures that indicate that bodies in the Kuiper Belt have been moved and shuffled by significant outward migration of Uranus and Neptune, complicating the task of uncovering links between composition and nebular conditions.  Ground- based visible to near-infrared (VNIR; 0.4 to 2.5 microns) spectra of the largest bodies (Pluto, Eris, Makemake) are dominated by methane. VNIR spectra of smaller (and therefore fainter) Kuiper Belt objects (KBOs) generally have fairly low S/N, precluding detailed compositional analysis.   The James Webb Space Telescope (JWST) opens a new era in spectral observations of KBO.  The NIRSpec instrument extends spectral observations to 5.3 microns, a region that includes strong fundamental vibrational modes of many ices and organics of thought to populate these surfaces, and the sensitivity, even in this new wavelength range, is extraordinary.  In this talk, I will present results of spectroscopy of KBOs and related populations from the first year of JWST observations.  These highlights will include measurement of isotopic signatures in the methane on the largest bodies, discovery of three distinct spectral groups among the smaller bodies that likely map to ice retention lines in the early Solar System, irradiation chemistry on intermediate sized (D~1000 km) bodies, spectral support for binary formation from streaming instabilities, and spectra of Trojan asteroids, which are thought to be KBOs that were scattered inward and stored at 5.2 AU for 4.5 Gyr. Bio: Dr. Emery applies the techniques of astronomical reflection and emission spectroscopy and spectrophotometry of primitive and icy bodies in the near- (0.8 to 5.0 microns) and mid-infrared (5 to 50 microns) to investigate the formation and evolution of the Solar System and the distribution of organic material. The Jupiter Trojan asteroids have been a strong focus of his research, and he also regularly observes Kuiper Belt objects, icy satellites, and other asteroid groups to understand the state of their surfaces as related to these topics. Along with telescopic observations, he contributes to Solar System exploration as a science team member on the OSIRIS-REx asteroid sample return mission, the Lucy Trojan asteroid flyby mission, and the NEO Surveyor Mission infrared telescope mission. Learn More: Read his faculty bio on the Northern Arizona University Astronomy & Planetary Science page Find our more about his experience as a planetary astronomer here Event Location: HENN 318
Event Time: Thursday, March 14, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 202
Add to Calendar 2024-03-14T16:00:00 2024-03-14T17:00:00 Casting a Wide Net for Dark Matter Event Information: Abstract:I will discuss the need to extend the Standard Model of particle physics in order to describe the dark matter, a mysterious substance whose existence can be inferred from cosmological measurements, but whose fundamental nature remains unknown.  I’ll discuss how a broad strategy of searching for dark matter using techniques from particle physics and astronomy maximize our chances of successfully discovering its identity, and what this could mean for future research in particle physics. Bio: Tim M.P. Tait is a Chancellor's Professor of Physics and Astronomy at the University of California, Irvine. His research interests include theoretical investigations of physics beyond the Standard Model of particle physics, particle physics phenomenology, high energy collider physics, and cosmology and involves both exploring new models and new phenomena, as well as theoretical interpretation of experimental results. He is a fellow of the American Physical Society and recipient of the Friedrich Wilhelm Bessel-Forschungspreis from the Alexander von Humboldt Foundation. Tait received a Ph.D. in physics from Michigan State University and did postdoctoral work at Argonne National Lab and the Fermi National Accelerator Laboratory.   Learn More: Discover more from his homepage here See his faculty webpage at the University of California, Irvine here View his CV  Browse through his Wikipedia page Event Location: HENN 202
Event Time: Thursday, March 14, 2024 | 11:00 am - 12:00 pm
Event Location:
HENN 318
Add to Calendar 2024-03-14T11:00:00 2024-03-14T12:00:00 Pushing the Limits of Cosmology with Next-Generation Millimeter-Wave Telescopes Event Information: Abstract: While the Lambda-CDM model is remarkably effective at describing the Universe and its evolution as a whole, foundational questions remain about the origin of the primordial fluctuations, the physics of the present-day acceleration, and the astrophysics of the first billion years. Maps of large-scale structure throughout the full history of the Universe can answer these questions. I will discuss our plans to test cosmic inflation with the "ultimate" ground-based cosmic microwave background experiment, CMB-S4. I will then introduce millimeter-wave line intensity mapping---a new probe for measuring large-scale structure well into the first billion years---and the SuperSpec on-chip mm-wave spectrometer that my team is developing to enable this measurement. Finally I will discuss the SPT-SLIM pathfinder experiment, and how future line intensity mappers will characterize the dynamics of reionization and test the physics of inflation and dark energy. Event Location: HENN 318
Event Time: Thursday, March 14, 2024 | 9:45 am - 10:45 am
Event Location:
BRIM 311
Add to Calendar 2024-03-14T09:45:00 2024-03-14T10:45:00 Multiscale Modeling of Mechanical Deformation in Chemically Complex Alloys Event Information: Abstract: In my presentation, I will give an overview of three primary areas that have been my focal research interests at NOMATEN CoE: i) crystal and amorphous plasticity, ii) transport properties of high-entropy alloys (HEAs), and iii) micro-structural informatics. In i), my research has employed statistical physics to unravel the microscopic basis of plasticity based on the collective dynamics of shear transformation zones in amorphous solids as well as dislocations mechanics in crystalline metals. Within the context of HEAs, my focus has been on the role of chemical complexities (i.e. local disorder/ordering) investigating their impact on alloy strengths. In ii), I have explored the sluggish diffusion of defects in HEAs and its impact on thermo-mechanical properties. In the area of micro-structural informatics in iii), I have utilized the power of machine learning (ML) and graph neural networks GNNs to infer (hardness) properties solely based on the (surface) microstructural information. Building upon these achievements, we are currently expanding the scope of the above studies by i) employing ML to identify relevant microstructural metrics for predicting bulk plastic properties in bulk metallic glasses as well as HEAs within the microstructure-property paradigm, ii) utilizing machine-learned interatomic potentials for accelerated material discovery, and iii) extending the GNN’s capabilities to infer microstructural signatures and defects based on micro/nano mechanical response (as input data) in different metallic systems and distinct alloy compositions. Speaker Bio: Kamran Karimi is a computational materials physicist working at the National Centre for Nuclear Research, Otwock Poland. Event Location: BRIM 311
Event Time: Tuesday, March 12, 2024 | 5:30 pm - 7:30 pm
Event Location:
HENN 200
Add to Calendar 2024-03-12T17:30:00 2024-03-12T19:30:00 Undergraduate Science Slam Event Information: Science Communication skills are key for success in all sciences! Being able to explain a complex scientific idea, or theory clearly to a general audience can show your mastery of a subject, sell your research, or successfully launch a start-up! PHAS Outreach has partnered with Science Slam Canada to bring this science communication opportunity to our students! Cheer on our physics & astronomy undergrads as they compete in 5-minute challenges for science clarity as they share their mastery with you! If you understand the science...they get points. There will be prizes for audience members and the top slammer. For undergrad students in Science or Arts - come see what science communication is all about. Cheer on our slammers! Want to learn more about our programs? Stay after the competition to meet students and advisors and learn what we have to offer.  Pizza and drinks included in this evening event! Registration required as space is limited - Sign up today!  Event Location: HENN 200
Event Time: Monday, March 11, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
Add to Calendar 2024-03-11T16:00:00 2024-03-11T17:00:00 Surveying the Sky with Rubin Observatory Event Information: Abstract: Rubin Observatory is on track to start operations of the Legacy Survey of Space and Time (LSST) in fall 2025, setting off a rush of data that will be massive (20TB per night) and nonstop for ten years. The LSST will survey approximately 20,000 square degrees of sky in ugrizy bandpasses, with highly accurate astrometry and photometry, with individual images reaching depths of about 24.5 in r band. Construction of Rubin has been a long road, starting around 2000, becoming one of the top priorities of the 2010 Astronomy and Astrophysics Decadal Survey recommendations, pushing through COVID -- but commissioning starts this summer and survey operations are on track to start in fall 2025. The core science drivers for the LSST are constraining dark energy and dark matter, mapping the Milky Way and Local Volume, inventorying the Solar System, and opening new windows on the Transient and Variables Sky. To support these goals, the LSST footprint includes a "Wide Fast Deep" (WFD) region that will receive on the order of 800 visits per pointing, along with additional "mini-survey" coverage of the ecliptic, the galactic plane, and the south celestial pole. The survey plan also includes five Deep Drilling Fields, a few hundred square degrees which receive more than 10x the coverage of the WFD, as well as the possibility for additional "micro-surveys" requiring less than ~1% of the total survey time.  Final (10 year) coadded depths for the 18,000 square degrees in the WFD footprint of the survey will reach approximately 27th magnitude in r band. Photometric redshift measurements are expected to be accurate to 1-3% over a range of 0.2 to 3 in redshift. On the order 20 billion galaxies and 17 billion resolved stars will be reported in the resulting catalogs. Astrometry is expected to be accurate to about 50 mas (10 mas relative precision) with photometric accuracy of 10 mmag. "Alerts" for each visit, coming from difference imaging, will provide immediate insight into real-time events captured by the survey. On the order of 10 million alerts are expected per night. With multiple measurements per night, typically supplemented by additional visits in the next few days, including information from multiple bandpasses, the alert stream passes a rich source of information about transient and variable phenomenon to the astronomical community. Moving objects will be linked into detections of Solar System objects, with approximately 6 million objects expected to be discovered -- a large fraction of which will be characterized with lightcurve measurements, allowing determination of colors, rotation periods, and phase curves.  Bio:                       Lynne Jones is the LSST Performance Scientist, working with Rubin Observatory. She is currently working on the optimization of the LSST survey strategy. She studies small objects throughout the Solar System, with a particular interest in surveys for distant TransNeptunian Objects and lightcurve properties of asteroids. She is currently located in Victoria, BC.    Learn More: See Lynne's Bio from the Institute for Data Intensive Research in Astrophysics & Cosmology (DiRAC) Explore the Rubin Observatory Explore the Legacy Survey of space and time (LSST)    Event Location: HENN 318
Event Time: Monday, March 11, 2024 | 11:00 am - 12:00 pm
Event Location:
HENN 318
Add to Calendar 2024-03-11T11:00:00 2024-03-11T12:00:00 Visualizing Quantum Matter with Cryogenic Electron Microscopy Event Information: Abstract:  Quantum-mechanical effects and strong electron-electron interactions give rise to solids with superb electronic properties and a vast potential for future technologies. In many of these strongly interacting materials, electrons self-organize into new spatial patterns that break the symmetry of the underlying crystal. A grand challenge in the field is to understand the nature of these symmetry-breaking states and to overcome their tendency to form inhomogeneous textures at the nanoscale. Towards that goal, atomic-resolution transmission electron microscopy techniques hold immense promise for advancing quantum materials research; however, progress has been hindered by the lack of low-temperature capabilities that are necessary to study quantum systems.  Here I will show vivid atomic-scale visualizations of electronic order in strongly correlated oxides enabled by the development of cryogenic scanning transmission electron microscopy (cryo-STEM). This novel technique enables direct visualizations of (i) the picoscale atomic displacements governing electronic transitions in quantum materials, (ii) the nature and symmetry of charge/orbital order, and (iii) a complex nanoscale landscape involving topological defects, phase competition, and inhomogeneity. Finally, I will describe our recent and unique approach that has enabled cryogenic electron microscopy with liquid helium cooling and atomic resolution. These capabilities pave the way for novel explorations of ultra-low temperature quantum phenomena in the electron microscope.    Bio:  Ismail El Baggari is a Principal Investigator and Fellow at the Rowland Institute at Harvard. He obtained his Ph.D. and M.S. in Physics from Cornell University working with the late Prof. Lena Kourkoutis and a Bachelor of Science in Applied Physics from Yale University. His research focuses on the development of in situ cryogenic electron microscopy for understanding quantum materials and devices. Event Location: HENN 318
Event Time: Friday, March 8, 2024 | 10:30 am - 12:30 pm
Event Location:
BUCH D319 (Buchanan Bldg, 1866 Main Mall)
Add to Calendar 2024-03-08T10:30:00 2024-03-08T12:30:00 Control of Molecular Rotation in Superfluid Helium Event Information: Abstract: This work outlines the control of molecular rotation in superfluid helium using nonresonant laser fields. Experiments within bulk superfluid 4He demonstrate control over the rotational frequency and direction of rotation of electronically excited helium dimers (excimers), which are created in nanometre-scale bubbles in the fluid. The excimers rotate for thousands of rotational periods, indicating relatively weak but nonzero coupling to the surrounding helium. Controlling the rotation of molecules therefore serves as a probe of superfluid helium, and its coupling to impurities. The weak coupling is attributed to the fact that helium dimers rotate with rotational energy well above that of the expected excitations of the surrounding helium.  By studying other molecules embedded in helium nanodroplets, we are able to explore the rotation of molecules below, near, and above this energy scale. The influence of strong coupling to the helium becomes extreme when the energies are comparable, severely distorting observed rotational spectra.  Results presented here demonstrate that the rotation of molecules in helium nanodroplets may be controlled in the same manner as molecules in the gas phase. Experiments using an optical centrifuge to attempt to control molecular rotation in helium nanodroplets, and analysis regarding the results, are presented, as well as the first experiments studying rotationally excited nitrogen in helium nanodroplets. Experimental results rotationally exciting nitric oxide dimers in helium nanodroplets present a suitable candidate as a molecule for further study. Alignment of the molecule offers insights to its anisotropic polarizability, and upon rotational excitation, long-lasting rotation exhibits a stronger observable than previously-studied molecules whose rotational energy may be controlled within the desired range.  Event Location: BUCH D319 (Buchanan Bldg, 1866 Main Mall)
Event Time: Monday, March 4, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
Add to Calendar 2024-03-04T16:00:00 2024-03-04T17:00:00 Shedding Light on Electromagnetic Counterparts Across the Gravitational Wave Spectrum Event Information: Abstract:  Gravitational wave astronomy is entering a golden era of discovery, and many key science goals of this new frontier rely on 'multi-messenger’ observations that leverage the combination of both 'cosmic messengers' of gravitational waves and light.  I will discuss two recent advances from my research group in understanding the electromagnetic counterparts of gravitational waves across the gravitational wave spectrum. First, I will discuss how the origins of the heaviest elements can be probed, through inferring the abundance pattern of r-process elements produced in binary neutron star mergers from optical spectroscopy of their resultant kilonova explosions. Second, I will discuss how to identify the host galaxies of supermassive black hole binaries that will soon be detected by pulsar timing array experiments, based on their unique morphological and stellar kinematic properties. Bio:   I am a multi-wavelength astronomer, and my research group is focused primarily on using multi-messenger gravitational wave observations to study kilonova astrophysics, r-process nucleosynthesis, black hole accretion, and cosmology. Most recently, I have become interested in applications of machine learning to computationally-intractable inference problems in astrophysics. For more information, please see the ‘Research Program’ page. I began my research career as an undergraduate at Columbia University in New York, NY, and did my PhD at the University of Washington in Seattle, WA. For my PhD, I worked primarily on observations of active galactic nuclei variability, but also dabbled in a diverse variety of other areas, including cosmological simulations of galaxy formation, cosmic microwave background secondary anisotropies, and software infrastructure for the Sloan Digital Sky Survey. I then moved to McGill University in Montréal, QC, as a McGill Space Institute Postdoctoral Fellow. There, I began working in the exciting new field of multi-messenger gravitational wave astrophysics, before finally joining the faculty at Bishop’s University in Sherbrooke, QC.   Learn More: View his website here Read Bishop's University article: Dr. John Ruan is Appointed Canada Research Chair in Multi-Messenger Astrophysics See Bishop's University blog on Prestigious scholars here Event Location: HENN 318
Event Time: Monday, March 4, 2024 | 12:30 pm - 1:30 pm
Event Location:
HENN 301
Add to Calendar 2024-03-04T12:30:00 2024-03-04T13:30:00 Higgs-Confinement Transitions in QCD from Symmetry Protected Topological Phases Event Information:   Bio: Thomas Dumitrescu received a B.A. in Physics and Mathematics from Columbia University in 2008, and a Ph.D. in Physics from Princeton University in 2013, under the supervision of Professor Nathan Seiberg at the Institute for Advanced Study. Before coming to UCLA, he was a five-year postdoctoral fellow at Harvard University. Professor Dumitrescu has broad interests in theoretical physics. His research spans many aspects of quantum field theory, including applications to particle and condensed matter physics, as well as supersymmetry, string theory, and mathematical physics. He is particularly interested in developing new theoretical tools for analyzing strongly-coupled quantum field theories, which are beyond the reach of conventional perturbation theory. Contact: Thomas Dumitrescu, Assistant Professor, Mani L. Bhaumik Presidential Endowed Term Chair in Theoretical PhysicsTEPOffice: PAB 4-939Phone: 310-825-3162Email: tdumitrescu@physics.ucla.edu Website: https://www.pa.ucla.edu/faculty-websites/dumitrescu.html   Event Location: HENN 301
Event Time: Monday, March 4, 2024 | 11:00 am - 12:00 pm
Event Location:
HENN 318
Add to Calendar 2024-03-04T11:00:00 2024-03-04T12:00:00 Beyond the Standard Model: Being Precise about the Unknown Event Information: Abstract: The Standard Model of particle physics cannot be the final word on how to understand fundamental particles theoretically. The missing pieces, intriguing patterns and extreme hierarchies of the Standard Model demand explanations, but any new theory must tread a tightrope of increasingly precise measurements.   In this talk I will describe recent work to chart the allowed space of new particles and interactions. By confronting general principles of field theory with the full array of experimental tests, this talk will highlight promising directions to uncover new physics. Bio: Sophie Renner is a particle theorist, whose work focuses on possible new particles and interactions beyond those of the Standard Model, and how they may be discovered at experiments. She received her PhD in 2016 from the University of Cambridge, and held postdoctoral research appointments at the University of Mainz, SISSA (Trieste), and CERN. She is currently a lecturer at the University of Glasgow.   Event Location: HENN 318
Event Time: Thursday, February 29, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 202
Add to Calendar 2024-02-29T16:00:00 2024-02-29T17:00:00 A new vision for the Center for Astrophysics | Harvard & Smithsonian Event Information: Abstract:I will present the latest discoveries and developments at the Center for Astrophysics | Harvard & Smithsonian (CfA).  Our discoveries cover solar astrophysics, star formation and evolution, galaxy formation & evolution, extrasolar planets, black holes, and cosmology.  I will describe the latest ground and space-based technological developments at the CfA, including new space satellites, and compelling new instrumentation for current and future ground-based telescopes in the optical, infrared, IR, and X-rays, as well as for climate science.  I will discuss our challenges with Petabyte scale datasets and the application of AI to astronomical problems.  Finally, I will provide an overview of the diversity, inclusion and culture initiatives that are being implemented at the CfA, using evidence-based studies from the literature. Bio:   Lisa Kewley is Director of the Center for Astrophysics | Harvard & Smithsonian.  She is Director of the Smithsonian Astrophysical Observatory, Director of the Harvard College Observatory, and Professor of astrophysics at the Harvard Department of Astronomy. Kewley obtained her PhD in 2002 from the Australian National University on the connection between star-formation and supermassive black holes in galaxies.  She was a Harvard-Smithsonian Center for Astrophysics Fellow and a NASA Hubble Fellow.  Her awards include the 2006 American Astronomical Society Annie Jump Cannon Award, the 2008 American Astronomical Society Newton Lacy Pierce Prize, and the 2020 US National Academy of Science James Craig Watson Medal. In 2014, Kewley was elected Fellow of the Australian Academy of Science “for her fundamental advances in understanding of the history of the universe, particularly star and galaxy formation”, and in 2015, Kewley was awarded an ARC Laureate Fellowship, Australia’s top fellowship to support excellence in research. In 2020, Kewley was awarded the US National Academy of Sciences James Craig Watson Medal, in 2021 she was elected to the US National Academy of Sciences, and in 2022 she was elected to the American Academy of Arts and Sciences.  From 2017-2022, Kewley implemented her scientific vision through her Australian Research Council Centre of Excellence in All-Sky Astrophysics in 3D (ASTRO 3D). In July 2022, Kewley became Director of the Center for Astrophysics | Harvard & Smithsonian.  At the CfA, she is implementing an ambitious new vision for the next generation space and ground-based telescopes, petabyte-scale data handling, new diversity and inclusion initiatives, and nation-wide education and outreach programs.   Learn More: See her webpage at the Center for Astrophysics View her bio at the Smithsonian Read her wikipedia page  Event Location: HENN 202
Event Time: Thursday, February 29, 2024 | 11:00 am - 12:00 pm
Event Location:
HENN 318
Add to Calendar 2024-02-29T11:00:00 2024-02-29T12:00:00 Observation of Pines' Demon in Sr2RuO4 Event Information: Abstract:Electrons confined in a material exhibit rich quantum behavior with no counterpart in free space. In particular, electron-electron interactions give rise to quantized collective particles which we can use to fundamentally understand the properties of materials. For metals, the primary collective mode of electrons is the plasmon - a quantized excitation where all the electrons move together in synchrony. In 1956, David Pines predicted another particle, known as the "demon", inside multiband metals where electrons of different "flavors" move out-of-phase with each other. For over 66 years, the demon remained undetected because demons are both gapless (i.e. massless) and do not couple to light. Nevertheless, demons are predicted to be responsible for diverse phenomena ranging from phase transitions in mixed-valence materials, "soundarons" in Weyl semimetals, and superconductivity in, for example, metal hydrides. In this talk, I will present evidence for the demon in Sr2RuO4 using the newly developed technique of Momentum-resolved Electron Energy-Loss Spectroscopy (M-EELS). Our study confirms the existence of Pines' demon and indicates that demons may be a pervasive feature of multiband metals. Finally, I will discuss emerging experimental efforts for discovering new collective particles in quantum materials that have escaped experimental identification. Bio:Ali Husain received his B.S. in Physics from the University of California, Berkeley in 2014. In 2020, he completed his Ph.D at the University of Illinois at Urbana-Champaign in condensed matter physics focusing on the problem of charge dynamics in so-called "strange" metals. From 2020-2022, Ali was the SBQMI Postdoctoral Prize Fellow at the University of British Columbia working with George Sawatzky and Steven Dierker to develop new methods for studying quantum materials using electron microscopy and spectroscopy. Since 2022, Ali has been an AMO research scientist at Quantinuum building next-generation trapped-ion quantum computers. Event Location: HENN 318
Event Time: Thursday, February 29, 2024 | 9:45 am - 10:45 am
Event Location:
BRIM 311
Add to Calendar 2024-02-29T09:45:00 2024-02-29T10:45:00 Quantum sensing in the solid-state: from one spin to many spins Event Information: Abstract: Sensors that leverage quantum phenomena to measure physical quantities harbor many attractive features beyond classical sensors. Solid-state quantum sensors, with the nitrogen-vacancy (NV) center in diamond a forefront technology, are particularly attractive for their compatibility with biological and condensed matter systems, offering ultra-high spatial resolution and sensitivity over a wide temperature range, while being quantitative and non-invasive. Here I first present our group’s work on NV-center-based scanned probe imaging of electron flow patterns in graphene, revealing the presence of hydrodynamic electron flow. A frontier of quantum sensing is the utilization of entangled quantum sensors for metrological advantage, a goal not yet realized in the solid-state. I also discuss our group’s progress towards realizing novel many-body states of entangled spins, both diamond-based qubits and novel chemically-assembled molecular spin systems. Speaker Bio: Ania Bleszynski Jayich is a professor of physics at the University of California Santa Barbara, where she holds the Bruker Endowed Chair for Science and Engineering, the Elings Endowed Chair for Quantum Science, and is co-director of the Quantum Foundry, an NSF Q-AMASE-I center. Her research interests include quantum assisted sensing and imaging on the nanoscale, spin-coupled optomechanics, and hybrid quantum systems for sensing and quantum information. Before coming to UCSB, Ania was a postdoctoral researcher at Yale University, and received her PhD in physics from Harvard in 2006 and a B.S. in physics and mathematical and computational science from Stanford in 2000. Event Location: BRIM 311
Event Time: Tuesday, February 27, 2024 | 11:00 am - 12:00 pm
Event Location:
HENN 318
Add to Calendar 2024-02-27T11:00:00 2024-02-27T12:00:00 New frontiers in error correction and many-body physics: non-equilibrium quantum matter and non-Euclidean geometries Event Information: Abstract:  Error correction is a key ingredient towards realizing scalable quantum computation and is also of fundamental interest due to its close connection to exotic quantum phases of matter. In my talk, I will discuss some recent results at the interface of quantum error correction and quantum many-body physics. In the main part of the talk, I will discuss the problem of realizing error correction in a fully local way, without the need for non-local communication between a classical processor and the quantum device. This fits into the broader problem of classifying quantum phases of matter in dissipative open systems. I will formulate conditions for the stability of phases in open systems, putting it on a footing similar to the analysis of quantum phases of matter at zero temperature. In the last part of the talk, I will briefly discuss recent breakthroughs in the field of quantum low-density parity check (LDPC) codes, which live on highly expanding non-Euclidean graph geometries, and describe how they can be understood in the language of gauge theories, familiar from high energy and condensed matter physics. [1] Defining stable phases of open quantum systems, TR, Sarang Gopalakrishnan, Curt von Keyserlingk, arXiv 2308.15495 [2] The physics of (good) LDPC codes I: Gauging and dualities, TR, Vedika Khemani, arXiv 2310.16032  Bio: Tibor Rakovszky is a Bloch Postdoctoral Fellow in Quantum Science and Engineering at Stanford University. Previously, he completed his PhD at the Technical University of Munich in 2020. His PhD work focused on dynamics in interacting quantum systems, combining ideas from quantum information theory and many-body physics to understand the scrambling of quantum information and its relationship to thermalization and transport in closed quantum systems. He subsequently extended these studies to include the effects of local measurements on quantum dynamics. His more recent interests are at the intersection of quantum error correction and many-body physics. In particular, he is interested in the classification of quantum phases of matter in novel regimes and the use of such phases for storing and manipulating quantum information.  Event Location: HENN 318
Event Time: Friday, February 23, 2024 | 9:30 am - 11:30 am
Event Location:
Henn 318
Add to Calendar 2024-02-23T09:30:00 2024-02-23T11:30:00 Atom-Atom, Atom-molecule and molecule-molecule collisions at ultra-cold and room temperature Event Information: Abstract:  This thesis describes experiments with magnetically and optically trapped  ultra-cold gases of 6Li and 85,87Rb atoms. We describe three distinct areas of investigation, with a common theme of probing collisions: the production of deeply bound 6Li2 dimers and a study of their reactive collisions, the use of ultra-cold atoms as a pressure sensor by measuring the loss rate due to collisions with background gases at room temperature, and progress towards investigating heteronuclear collisional resonances between ultra-cold 6Li and 85,87Rb. We report on the production of deeply bound triplet a(13Σ+u ) 6Li2 molecules in a single quantum state by stimulated Raman adiabatic passage. The ensemble lifetimes for these molecules were found to be limited by dimer- dimer collisions whose rate depends on the ro-vibrational state of the collision partners. The loss rate observed follows a universal prediction for the |v = 0, 5, 8; N = 0, 2⟩ states, and remarkably, a sub-universal rate for the |v = 9; N = 0⟩ state. We find that molecules in the ground state of the triplet potential are also collisionally unstable, consistent with theoretical predictions that molecules in any of the triplet levels are chemically unstable and decay due to a barrier-less trimer formation process.  We also report on a comparative measurement of the cross section for trap loss inducing collisions of 6Li and 87Rb atoms when exposed to various common background gases found in ultra-high vacuum (UHV) environments, including H2, He, Ne, N2, Ar, Kr and Xe. Ultra-cold 6Li and 85,87Rb atoms are used as a sensitive probe of the background gas pressure, with the quantity ⟨σlossv⟩ essential for converting the observed loss rate due to background gas collisions into a pressure measurement.  Finally, we discuss the production of ultra-cold mixtures of 6Li and 85,87Rb atoms, and the progress towards investigating heteronuclear Feshbach resonances. The Feshbach resonances allow us to tune the interaction strength, which is an essential tool for investigating few and many-body physics in these systems. We discuss the particular example of the Efimov effect, which would be a natural topic of study following our investigating of the Feshbach resonance spectrum.  Event Location: Henn 318
Event Time: Thursday, February 22, 2024 | 1:00 pm - 2:00 pm
Event Location:
BRIM 311
Add to Calendar 2024-02-22T13:00:00 2024-02-22T14:00:00 Electrons in twisted layers: design, surprise, and a new set of eyes Event Information: Abstract: When two atomically-thin layers of a material are stacked one atop each other, with a relative twist angle between them, properties can emerge that bear little resemblance to the behavior of the individual layers. Though much can be predicted and designed about such structures, I will share two vignettes about how my students aimed for a particular behavior but found something quite different. The first led to the discovery of the first experimentally-known “orbital magnet”, a ferromagnet in which the tiny microscopic magnets that align with each other are not electron spins but tiny circulating current loops. The second surprise was observation of resistance that skyrocketed with the application of a magnetic field, along with other striking electronic properties — this one took years to figure out, but we’ve recently explained it. Each of these two surprises turned out to be caused by a structural feature of the layered stack which had not previously been considered important. Finally, I’ll describe a refined approach to stacking and a newly-developed technique for mapping the structure of twisted layers, which together might help us get more repeatable control of structure and thus electronic properties in such twisted systems. Event Location: BRIM 311