Events List for the Academic Year
Event Time:
Monday, March 4, 2024 | 12:30 pm - 1:30 pm
Event Location:
HENN 301
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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
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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
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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
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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
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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
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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
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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
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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
Event Time:
Thursday, February 22, 2024 | 11:00 am - 12:00 pm
Event Location:
HENN 318
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2024-02-22T11:00:00
2024-02-22T12:00:00
Sculpting quantum many-body states and quantum error correcting codes with measurements
Event Information:
Abstract:
Quantum mechanics exhibits a stark dichotomy between unitary time-evolution and measurement. These aspects are further contrasted by the fact that traditional many-body quantum theory is developed solely based on unitary aspects. In this talk, I will explore two fruitful synergies that emerge from the interplay between many-body quantum physics and the non-equilibrium quantum dynamics that arises from measurements. First, I will show how measurements can be used to circumvent fundamental constraints imposed by unitary dynamics and efficiently prepare a large class of topological phases of matter. In addition to discovering a new hierarchy of many-body quantum states unseen in the unitary setup and a surprising connection to the unsolvability of the quintic polynomial, our studies also yield practical protocols for quantum processors that led to the first unambiguous observation of non-Abelian anyons. Second, I will show how insights from topological phases of matter can in turn contribute to a physical understanding of the newly introduced "Floquet" quantum error correcting codes, featuring a schedule of anticommuting measurements. I will demonstrate that periodicity in time is in fact not required, unlocking a more general construction of "dynamic codes" that are capable of not just error correction, but also fault-tolerant quantum computation.
Bio:
Nat Tantivasadakarn obtained his undergraduate degree from UC Berkeley, his Master's from the Perimeter Institute for Theoretical Physics and his Ph.D. from Harvard University. He is currently a Burke postdoctoral fellow at Caltech. His research interests explore the interplay between topological phases of matter, quantum error correction and computation, non-equilibrium quantum dynamics and generalized symmetries.
Event Location:
HENN 318
Event Time:
Thursday, February 15, 2024 | 11:00 am - 12:00 pm
Event Location:
HENN 318
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2024-02-15T11:00:00
2024-02-15T12:00:00
Long-lived superconducting quantum circuits toward fault-tolerant quantum computing
Event Information:
Abstract:Superconducting quantum circuits represent fully engineerable quantum systems, positioning them as a leading platform for large-scale quantum computing. Despite recent milestones like surface code demonstrations and achieving quantum supremacy, scaling up to millions of qubits for fault-tolerant operations remains a significant challenge. Our research focuses on enhancing qubit lifetimes within superconducting quantum circuits to reduce resource requirements significantly. We pursue two primary strategies: Firstly, we investigate the loss mechanisms affecting state-of-the-art superconducting qubit lifetimes. By careful optimization of the fabrication process, sample packaging, and cryogenic wiring, we demonstrate long-lived superconducting qubits, recording one of the best qubit lifetimes (> 0.5 milliseconds). By leveraging these long-lived qubits as quantum sensors, we identify a new loss mechanism attributed to mechanical shocks from the pulse tube cooler of a dilution refrigerator. This discovery suggests new error mitigation strategies by isolating superconducting qubits from mechanical environments. Secondly, we introduce mechanical oscillators based on circuit optomechanics, facilitated by a novel nanofabrication process involving silicon-etched trenches. This breakthrough enables the realization of ultra-coherent and highly scalable systems (> 10 milliseconds and > 20 modes), leading to the first demonstrations of tracking the thermalization of a mechanical squeezed state and engineering topological optomechanical lattices. These advancements not only bring insights into decoherence mechanisms but also pave the way for scalable fault-tolerant quantum computing.
Event Location:
HENN 318
Event Time:
Thursday, February 15, 2024 | 9:45 am - 10:45 am
Event Location:
BRIM 311
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2024-02-15T09:45:00
2024-02-15T10:45:00
Frustrated Quantum Devices: understanding how correlations, complex order and boundary states manifest in novel material functionalities
Event Information:
Abstract: Materials at the boundary of critical phase transitions are of significant fundamental interest, not least due because of their connection to unconventional superconductivity and quantum magnetism. One characteristic of such systems is the presence of coupled order parameters that underlie these phase transitions. Here, we explore how this coupling manifests in the response of these materials when driven out of equilibrium by applied currents. We demonstrate how magnetic and charge textures can be electrically manipulated, suggesting possible applications for exotic materials in spintronics technologies.
Event Location:
BRIM 311
Event Time:
Monday, February 12, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
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2024-02-12T16:00:00
2024-02-12T17:00:00
A machine learning lens on galaxy mergers in the nearby Universe
Event Information:
Abstract:
Merger events are thought to interrupt the otherwise gradual evolution of galaxies with short periods of intense change, simultaneously transforming galaxy morphologies, fueling bursts of star formation, and giving rise to high accretion rates onto central supermassive black holes. In this talk, I will demonstrate how machine vision techniques have fundamentally changed the way mergers are identified and studied and highlight new observational results that constrain the influence of mergers on the evolutionary trajectory of galaxies. While some of these results highlight the elegance of the current paradigm for hierarchical galaxy growth, others point to complications brought on by the multi-wavelength diversity of galaxies, stars, and supermassive black holes in the Universe.
Bio:
Bobby Bickley is an astronomy Ph.D. candidate at the University of Victoria (unceded Lekwungen territory, Victoria BC). He also holds a B.Sc. in mechanical engineering from the University of Connecticut. Bobby’s research interests are galaxy evolution, galaxy mergers, supermassive black hole & galaxy co-evolution, and the application of machine learning techniques to problems in astronomy.
Event Location:
HENN 318
Event Time:
Thursday, February 8, 2024 | 2:00 pm - 3:00 pm
Event Location:
TRIUMF Auditorium
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2024-02-08T14:00:00
2024-02-08T15:00:00
Megajoule Fusion Yields at the National Ignition Facility (shared with UBC)
Event Information:
Abstract:
With 192 laser beams delivering over 2 megajoules of energy to target, the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory (LLNL) is the world's most energetic laser system and, for the first time in a controlled laboratory setting, has demonstrated fusion ignition and target gain greater than 1. The NIF generates ignition conditions by precisely firing the lasers onto a target comprising a centimeter-tall cylinder inside of which is a millimeter-scale spherical shell filled with deuterium-tritium fuel. The fuel highly compresses, fusing the deuterium and tritium to release helium and large quantities of neutrons and energy. A series of advances over the course of decades were required to reach this stage - laser optical components, target fabrication precision, and implosion design. Building from here, the momentous demonstration of reproducible ignition paves the way for a new category of ignition science experiments as well as a broad array of materials and nuclear science studies within a novel regime of high energy density physics.
Bio:
Berzak Hopkins is a design physicist at Lawrence Livermore National Laboratory, focusing on inertial confinement fusion experiments on the National Ignition Facility (NIF). She has already has made a mark at NIF as part of the team that performed the first shots to show more energy coming out of the hydrogen fuel than was deposited in it. While still short of ignition – when the energy out is greater than that needed to spark the fusion reaction – it’s a big step forward.
Laura also runs a website designed to connect the public to science research. “My goals continue to be to pursue what challenges me and what I feel passionate about, both in the arena of scientific research as well as in science policy and politics”.
Learn More:
See Laura's bio from the Lawrence Livermore National Laboratory website
Review her research here
Event Location:
TRIUMF Auditorium
Event Time:
Thursday, February 8, 2024 | 10:00 am - 11:00 am
Event Location:
BRIM 311
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2024-02-08T10:00:00
2024-02-08T11:00:00
Ultrafast optoelectronic circuits
Event Information:
Abstract: Ultrafast optoelectronic circuits offer new opportunities for investigating and controlling the electrical responses of microstructured quantum materials and heterostructures at femtosecond timescales and THz frequencies. Based on metal waveguides and laser-triggered photoconductive switches, these chip-scale circuits can be interfaced to quantum materials to directly probe the ultrafast flow of electrical currents or perform near-field THz spectroscopy on length scales orders of magnitude smaller than the diffraction limit.
In this talk, I will present on my group’s activities using these circuits to study the electrical transport properties of quantum materials driven out of equilibrium by femtosecond laser pulses [1]. In monolayer graphene, we observe an anomalous Hall effect induced by circularly polarized light in the absence of an applied magnetic field [2]. The dependence of the effect on a gate potential used to tune the Fermi level reveals multiple features that reflect the formation of a photon-dressed, or “Floquet-engineered”, topological band structure. The results are a critical first step towards realizing and controlling light-induced topological edge states. I will also discuss our recent results on the Weyl semimetal Td-MoTe2, where we observe rectified photocurrents that scale linearly with the applied laser field. This scaling violates the perturbative description of nonlinear optics/transport, but can be explained by the formation of a photon-dressed magnetic Weyl semimetal state.
In the second part of my talk, I will present on my group’s efforts in using femtosecond voltage pulses generated on-chip to probe and manipulate gate-tunable van der Waals heterostructures embedded in plasmonic cavities. We perform near-field time-domain THz spectroscopy on these cavities to study the light-matter hybridization. We observe coherent plasmon cavity modes that can be tuned from the weak to ultrastrong coupling regimes with electrostatic gating and cavity geometry. These techniques, which we are extending to mK temperatures and strong magnetic fields, could be used to investigate and control a wide range of topological and strongly correlated phenomena in microstructured quantum materials and heterostructures that fall on the THz/meV energy scale.
Event Location:
BRIM 311
Event Time:
Wednesday, February 7, 2024 | 3:00 pm - 4:00 pm
Event Location:
Henn 318
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2024-02-07T15:00:00
2024-02-07T16:00:00
FPGA-based Data Acquisition and Instrumentation in Astrophysics Experiments
Event Information:
Abstract:
The recent advancement of Field-Programmable-Gate-Array (FPGA) technology has made them more appealing for experimental astrophysics. These experiments typically require fast and parallel processing of huge amount of data with customizable computation in terms of signal-processing chain and bit depth. Today, FPGAs come with a variety of high-speed Analog-to-Digital data converters (ADCs), high-speed serial transceivers and configurable interfaces for standard peripherals: DDR4, PCIe, 10G Ethernet. The integration of these blocks and the programmable fabric on the same chip provides lower power consumption, higher integration (or smaller footprint) which in turn helps scalability and flexibility needed for astrophysics experiments. Here, we present an example implementation of a 2-channel Spectrometer readout on Xilinx RFSoC 4x2 platform.
Event Location:
Henn 318
Event Time:
Wednesday, January 31, 2024 | 3:00 pm - 4:00 pm
Event Location:
Henn 318
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2024-01-31T15:00:00
2024-01-31T16:00:00
Remarks on Gravitational Waves from Spinning Neutron Stars
Event Information:
RECORDING AVAILABLE AT: https://drive.google.com/file/d/1xMX95y1b9v0X1tmEtx-WgEU-keszFKpZ/view?usp=sharing
Abstract:
I have not published on this topic for over 20 years, but I feel it could be useful to critically discuss some old and new articles and ideas.
My aim is to focus on the basic or almost basic physics.
Event Location:
Henn 318
Event Time:
Tuesday, January 30, 2024 | 11:00 am - 1:00 pm
Event Location:
MSL room 226 with a hybrid option
Zoom link: https://ubc.zoom.us/j/3770243649?pwd=Y2VCdXoxM0wyRFhQVWFlQ2RhQWFRQT09&omn=68781685568
Meeting ID: 377 024 3649 Passcode: 514771
Zoom link: https://ubc.zoom.us/j/3770243649?pwd=Y2VCdXoxM0wyRFhQVWFlQ2RhQWFRQT09&omn=68781685568
Meeting ID: 377 024 3649 Passcode: 514771
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2024-01-30T11:00:00
2024-01-30T13:00:00
Studies of supercoiling-induced denaturation within DNA plasmids using single-molecule Convex Lens-induced Confinement microscopy
Event Information:
Abstract: DNA, RNA and proteins, which drive life, have complicated, constantly changing structures. For example, DNA inside cells is supercoiled, and the amount of supercoiling is constantly under flux. This supercoiling can drive structural transitions, such as AT-rich regions in under-twisted DNA denaturing under physiological conditions. Such denatured regions may have important functions. For example, denatured DNA can act as targets for single-stranded binding proteins which help regulate gene expression. Thus, it is important to develop tools and studies to better understand these structures.In this thesis, we use single-molecule Convex Lens-induced Confinement(CLiC) microscopy in conjunction with chemical footprinting to study the biophysics of these denaturation sites, with a particular focus on the Far Upstream Element (FUSE) region of the c-myc oncogene. First, we studied the out-of-equilibrium dynamics of such denaturation after a temperature perturbation. We found that the rate of transition of the denaturation site was dependent on the direction of the perturbation, with plasmids that were heated first exhibiting a slower relaxation than plasmids that were chilled. We hypothesized that unidentified secondary structures caused this hysteresis. Second, we developed a fluorescent probe based on a molecular beacon to improve the CLiC microscopy oligo-DNA binding assay used for detecting single-stranded DNA. The final design was a stemless molecular beacon with a fluorophore on one end and a quencher on the other. This design allowed for a 10- to 100-fold increase in probe concentration used in this assay and enabled simultaneous measurements of the states of two denaturation sites within one plasmid. Finally, we studied competition between two denaturation sites within the same plasmid. We found that at low superhelicities only one site could open, while higher superhelicities allowed both to open within the same plasmid. However, we predicted that adding a specific second denaturation site would suppress the opening of the first, which we did not observe. Overall, this work provides new insights into the behaviour of DNA secondary structures, both out-of-equilibrium and under competition, and develops new tools to better study the structural biology of DNA.
Event Location:
MSL room 226 with a hybrid option
Zoom link: https://ubc.zoom.us/j/3770243649?pwd=Y2VCdXoxM0wyRFhQVWFlQ2RhQWFRQT09&omn=68781685568
Meeting ID: 377 024 3649 Passcode: 514771
Event Time:
Monday, January 29, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
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2024-01-29T16:00:00
2024-01-29T17:00:00
What do JWST Observations infer about Galaxy Formation and LCDM?
Event Information:
Abstract:
The biggest news story from the first year of the James Webb Space Telescope is the existence of many more high-redshift galaxies than previously expected. This has sometimes been taken to extreme levels by suggesting that our understanding of galaxy formation in the cold dark matter model is fundamentally broken. I will discuss some of these first year results and explain what they are really telling us. I will show several results from the CAnadian NIRISS Unbiased Cluster Survey, CANUCS, and discuss their impact on this area of research.
Bio:
I am a Senior Research Officer (Astronomer) working in the Canadian Astronomy Data Centre group. My research interests are primarily in cosmological evolution, particularly the growth of black holes and massive galaxies. I use data from radio to X-rays to identify and understand galaxies and quasars up to the highest redshifts known. I am involved in the development of future observatories the James Webb Space Telescope and the Square Kilometre Array.
Learn More:
See Chris' Herzberg website here
See his personal website here
Read more about the Canadian Astronomy Data Centre
Event Location:
HENN 318
Event Time:
Friday, January 26, 2024 | 12:00 pm - 1:00 pm
Event Location:
HENN 318
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2024-01-26T12:00:00
2024-01-26T13:00:00
The Callan Rubakov Effect
Event Information:
Abstract:
The Callan Rubakov Effect describes the interaction between (massless) fermions and a smooth monopole in 4d gauge theory. In this scenario, the fermions can probe the UV physics inside the monopole core which leads to interesting effects such as proton decay in GUT models. However, the monopole-fermion scattering appears to lead to out-states that are not in the perturbative Hilbert space. In this talk, we will review this issue and propose a new physical mechanism that resolves this long-standing confusion.
Bio:
T. Daniel Brennan is a Physics postdoc at UC San Diego. His research focuses on applying the framework of generalized global symmetries to study strongly coupled quantum field theories. Daniel was previously a postdoctoral fellow at the University of Chicago and received his PhD from Rutgers in 2019.
Event Location:
HENN 318
Event Time:
Thursday, January 25, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 202
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2024-01-25T16:00:00
2024-01-25T17:00:00
Discussion: The TA Experience in our Department
Event Information:
Abstract:
In our first colloquium next week, our course coordinator Megan Bingham will host a discussion about the TA experience in our department. At the end of 2023, we learned that filling TA positions, particularly Head TA positions, has been challenging. There are, of course, many different reasons why this is the case, including the need for TAs to focus on research and finishing their theses. However, there could be other issues that have to do with what being a TA actually entails and so an open discussion could be helpful. We therefore want to encourage our grad students to participate in the discussion and tell us about their good and not so good experiences. An important question in this context is how the department and instructors can support TAs better. (Think of it as a start/stop/keep survey). We invite instructors to listen and contribute productive ideas, but the bulk of the contributions should come from TAs.
The overall goal of the discussion will be to collect ideas that could lead to more enjoyable TA experiences; in turn, benefiting the students. To help us organize the discussion around common themes. we invite our grad students to provide input via an anonymous one-question survey on Qualtrics or an email to Megan (megan.bingham@ubc.ca) that will be treated confidentially. You will find the link here.
Event Location:
HENN 202