Events List for the Academic Year

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: 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 | 11:00 am - 12:00 pm
Event Location:
HENN 318
Add to Calendar 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
Add to Calendar 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: Monday, February 12, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
Add to Calendar 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
Add to Calendar 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
Add to Calendar 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
Add to Calendar 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
Add to Calendar 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
Add to Calendar 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
Add to Calendar 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
Add to Calendar 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
Add to Calendar 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
Event Time: Thursday, January 25, 2024 | 10:00 am - 11:00 am
Event Location:
AMPL 311
Add to Calendar 2024-01-25T10:00:00 2024-01-25T11:00:00 Many-Body Exciton Polariton Quantum Dynamics in Optical Microcavities based on two-dimensional Metal-Halide Semiconductors Event Information: Abstract: Two-dimensional analogs of metal-halide perovskites represent a promising platform for exciton-polariton-based technologies. They sustain strongly bound excitons that are stable at room temperature, readily enabling strong light-matter coupling at ambient conditions. In the strong coupling limit, uncoupled excitons have been mainly regarded as a reservoir for the polariton population. In this work, we posit that there is a bidirectional interplay between the uncoupled exciton dynamics and the polariton quantum dynamics. We fabricated a Fabry-Pérot microcavity, enclosing a two-dimensional hybrid organic-inorganic lead-iodide semiconductor, and resolved the multi-particle correlations of exciton-polaritons — that is their population and coherence dynamics — employing excitation correlation photoluminescence and two-dimensional coherent excitation spectroscopies. We find (i) an increased exciton bimolecular scattering rate of the exciton reservoir in the microcavity relative to the bare semiconductor; (ii) ultrafast population transfer from the uncoupled exciton states and the middle polariton to the lower polariton; and (iii) two-quantum correlations between polaritons and uncoupled excitons. Our work quantifies many-body correlations between bare excitons and exciton-polaritons, which are fundamental in mechanisms of the formation of polariton condensates. Speaker Bio: Carlos Silva-Acuña is the Director of the Courtois Institute and a Professor at the Department of Physics at Université de Montréal. Event Location: AMPL 311
Event Time: Wednesday, January 24, 2024 | 3:00 pm - 4:00 pm
Event Location:
Henn 318
Add to Calendar 2024-01-24T15:00:00 2024-01-24T16:00:00 Searching for continuous gravitational-wave emission associated with stochastic radiometer candidates Event Information: Abstract: Continuous gravitational waves (CWs) from spinning, non-axisymmetric neutron stars can reveal novel insights into the physics of neutron star interiors, but have so far gone undetected. Searches for CWs in gravitational-wave interferometer data generally assume a phase-coherent signal over the observation period. Un-modelled methods, such as the All-Sky All-Frequency (ASAF) radiometer search for stochastic gravitational waves, may reveal CW signals which randomly wander in frequency, e.g. due to spin-up glitches or accretion torques. I will present results from a CW search of Advanced LIGO data from the third observing run (O3), which targets these ASAF sub-threshold candidates. Our search algorithm combines template-based matched filtering techniques with the Hidden Markov model (HMM) formalism, allowing the signal to undergo a random walk in frequency. We find no convincing evidence of CWs associated with the ASAF candidates in O3 data. We estimate our sensitivity by running the search on simulated signals. Event Location: Henn 318
Event Time: Monday, January 22, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
Add to Calendar 2024-01-22T16:00:00 2024-01-22T17:00:00 How do environmental processes quench cluster galaxies? Event Information: Abstract: The Virgo Environment Traced in CO Survey (VERTICO) is an Atacama Large Millimeter/submillimeter Array Large Program that has mapped the distribution and kinematics of star-forming molecular gas across 51 Virgo Cluster satellite galaxies on sub-kpc scales.  In this talk, I will showcase VERTICO results revealing how environmental mechanisms actively remove molecular gas, alter its distribution, and change the composition of the interstellar medium in cluster galaxies. I will also show that ram pressure stripping systematically increases molecular gas densities and triggers star formation activity on the leading half of the galaxy during the early stages of cluster infall, while lengthening gas depletion times and quenching galaxies in the latter stages.   Bio: How do galaxies evolve? is the question at the heart of my research. In search of answers, I examine the relationships between the gas in galaxies - as the fuel for forming new stars - and their stellar, star formation, and chemical properties. My specialism lies in the analysis of large multi-wavelength datasets in order to understand galaxy populations as a whole. I lead VERTICO, the Virgo Environment Traced in CO survey, an ongoing ALMA Large Program that is investigating the effect of extreme environments on galaxies by mapping the star-forming molecular gas in 51 galaxies in our nearest galaxy cluster, Virgo. VERTICO is the first ever Canadian-led ALMA Large Program and our team is made up of world-class researchers from all over the world who are working to reveal the physical mechanisms that drive galaxy evolution in dense environments in brilliant detail.   Learn More: View Toby's website here: https://drtobybrown.com See his Youtube video on Extreme Cosmos here; see his Vimeo video from FameLab Australia on how Dark Matter shapes the universe here. Learn about VERTICO the Virgo Environment Traced in CO survey.    Event Location: HENN 318
Event Time: Tuesday, January 16, 2024 | 11:00 am - 1:00 pm
Event Location:
Henn 318 and Zoom

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Add to Calendar 2024-01-16T11:00:00 2024-01-16T13:00:00 Dosimetry and biodistribution of actinium radiopharmaceuticals for targeted alpha therapy Event Information: Abstract: Targeted alpha therapy (TAT) combines an alpha emitting radioisotope with an appropriate biological targeting molecule to selectively bind to cancer cells and deliver highly localised cytotoxic radiation while sparing healthy non-targeted tissues. The alpha emitter actinium-225 (225Ac) has demonstrated promising clinical outcomes in patients with advanced metastatic disease, yet there remain unmet needs for quantitative and accurate methods to directly detect 225Ac-labelled radiopharmaceuticals in vivo. This thesis presents computational and experimental methods to evaluate the biodistribution and dosimetry of Ac-radiopharmaceuticals. 225Ac (t1/2 = 9.9 d) is a potent therapeutic isotope due to its four alpha emissions throughout its decay chain, however, it is only detectable via gamma emissions from its progeny 221Fr and 213Bi, which can relocate from targeted sites. Monte Carlo simulations were conducted to evaluate dosimetry estimates in cancer cells and micrometastasis and to assess the effect of progeny retention on the absorbed therapeutic dose. Direct detection of Ac-radiopharmaceuticals in vivo is required for assessing pharmacokinetics accurately. 226Ac (t1/2 = 29.6 h) was selected as an ideal Ac-isotope for element equivalent diagnostics of 225Ac due to its gamma emissions at 158 keV and 230 keV, ideal energies for single photon emission computed tomography (SPECT) imaging. 226Ac was produced at TRIUMF with its Isotope Separator and Accelerator (ISAC) facility in quantities up to 37 MBq for proof-of-concept and feasibility studies. Quantitative 226Ac SPECT imaging was characterized with a small animal SPECT/CT scanner in a phantom study designed to assess its performance with respect to contrast, noise, and resolution. The feasibility of preclinical imaging with high quantitative accuracy and spatial resolution was established and motivated the first ever attempts to image 226Ac in vivo. SPECT imaging with 226Ac was demonstrated in vivo with both a preclinical radiopharmaceutical and free 226Ac activity. Image-based activity measurements correlated well with ex vivo biodistribution measurements. As an alpha emitter itself, 226Ac was also evaluated for its standalone theranostic potential. Dosimetry from a preclinical 226Ac-labelled radiopharmaceutical was estimated with Monte Carlo simulations and ex vivo biodistribution measurements. A longitudinal therapy study demonstrated anti-tumour properties with no observable toxicities. Event Location: Henn 318 and Zoom https://ubc.zoom.us/j/66307083128?pwd=U2hqdXZRWjdnVnE4aEIrWVk2dkhOQT09 Meeting ID: 663 0708 3128 Passcode: 123 One tap mobile +17789072071,,66307083128#,,,,,,0#,,123# Dial by your location +1 778 907 2071 (Vancouver) +1 647 374 4685 (Toronto) +1 647 375 2970 (Toronto) +1 647 375 2971 (Toronto) +1 204 272 7920 (Manitoba) +1 438 809 7799 (Montreal) +1 587 328 1099 (Alberta) +1 613 209 3054 (Ottawa) Join from a videoconferencing system IP: 65.39.152.160 Meeting ID: 663 0708 3128 Passcode: 123 SIP: 66307083128@vn.zmca.us Passcode: 123
Event Time: Monday, January 15, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
Add to Calendar 2024-01-15T16:00:00 2024-01-15T17:00:00 The CO Mapping Array Galactic Plane Survey Event Information:   Abstract: The CO Mapping Array Project Galactic Plane Survey (COMAP GPS) is a radio continuum and radio recombination line survey between 26 and 34 GHz at a resolution of 4.5 arcminutes. The survey will span Galactic longitudes of 20 < l < 270 and latitudes of |b| < 2 with an expected completion date in 2025. Complimenting COMAP's main cosmological goals (mapping star formation history through observing the redshifted CO-line) the COMAP GPS aims to investigate star formation by observing Galactic Hii regions, producing the highest-resolution Galactic AME catalogue to date and creating diffuse emission templates for better subtraction of Galactic emission from CMB maps. In this talk, I will present our first published results from the COMAP early science series, alongside a sneak peek at the next wave of results to be published in the coming months - many of which focus on the search for spinning dust emission (AME) at scales of a few arc-minutes. I will discuss our first AME searches in the region around Westerhout 43, alongside our latest results following up on the QUIJOTE and Planck AME catalogues (Poidevin et al., 2023, Planck Int. XV). I will show how COMAP data allows us to localise AME to specific sub-structures in these vast complexes - notably in W47 and W52. Finally, I will discuss our next results from an extension of the survey to Barnard 30 in the Lambda Orionis region.  Bio: Thomas Rennie is a new postdoc in the Department of Physics & Astronomy.   Learn More: Learn more about COMAP Read about this project and Thomas' involvement as a PhD student here Event Location: HENN 318
Event Time: Friday, January 12, 2024 | 3:00 pm - 5:00 pm
Event Location:
https://ubc.zoom.us/j/67710585936?pwd=cE9kQzEvcHppMjJ4VmI5bkFvSDRpdz09 Passcode: 667047
Add to Calendar 2024-01-12T15:00:00 2024-01-12T17:00:00 Cardiac radiosurgery motion management – investigation of regional myocardial motion and cardiac gating Event Information: Abstract: Ventricular tachycardia (VT) is an abnormally rapid heart rhythm that can be life-threatening, leading to severely diminished cardiac output or sudden cardiac death. VT predominantly arises from scarred myocardium, where re-entrant electrical circuits cause continuous re-excitation. Cardiac radiosurgery is a non-invasive treatment for VT, where a linear accelerator is used to irradiate the arrhythmogenic scar region. Target motion management in cardiac radiosurgery can be challenging due to the complex combination of cardiac and respiratory motion. An internal target volume (ITV) approach is most commonly used to encompass the entire motion, but inaccurate or excessive margins may lead to suboptimal outcomes or adverse effects. There is a significant need for research towards improved motion management strategies in cardiac radiosurgery. In particular, cardiac gating has not been thoroughly investigated -- treating only during minimal motion periods of the cardiac cycle would allow for smaller treatment margins and reduced dose to surrounding areas. The first aim of this thesis was to quantify cardiac-induced motion – cardiac magnetic resonance (CMR) images were analyzed to assess regional left ventricle (LV) motion for hearts with varied cardiac function, ranging from healthy to severely reduced ejection fraction. Data is presented for epicardial and endocardial displacement in all LV segments and for each patient group, providing reference data for improved cardiac treatment margins. For regions of the LV with significant cardiac-induced motion, cardiac gating would be beneficial. A cardiac-synchronized volumetric modulated arc therapy (CSVMAT) proof-of-principle technique was demonstrated, where a treatment plan synchronized to an electrocardiogram (ECG) signal was delivered on a Varian TrueBeam linear accelerator. The radiation beam was successfully synchronized with a variable heart rate, and film dosimetry showed excellent dose distribution agreement with the original plan. After demonstrating the feasibility of cardiac gating on a linear accelerator, the potential benefits of a cardiac-gated radiosurgery treatment were assessed. CMR images were analyzed to compare LV segment-specific displacements and treatment areas for gated and non-gated treatments. This work demonstrated that cardiac gating has the potential to significantly reduce treatment volumes for cardiac radiosurgery, depending on patient characteristics and the region of the heart to be treated. Event Location: https://ubc.zoom.us/j/67710585936?pwd=cE9kQzEvcHppMjJ4VmI5bkFvSDRpdz09 Passcode: 667047