Events List for the Academic Year
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
Event Time:
Thursday, January 25, 2024 | 10:00 am - 11:00 am
Event Location:
AMPL 311
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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
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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
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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
https://ubc.zoom.us/j/66307083128?pwd=U2hqdXZRWjdnVnE4aEIrWVk2dkhOQT09
Meeting ID: 663 0708 3128
Passcode: 123
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Meeting ID: 663 0708 3128
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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
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Meeting ID: 663 0708 3128
Passcode: 123
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Event Time:
Monday, January 15, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
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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
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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
Event Time:
Thursday, January 11, 2024 | 10:00 am - 12:30 pm
Event Location:
https://ubc.zoom.us/j/4747189913?pwd=RHEvdjJ3NWU3TTVCdkZGdHVsWlpOQT09&omn=64712444179 Passcode: 123
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2024-01-11T10:00:00
2024-01-11T12:30:00
Towards improving radiotherapeutic treatment of the parotid glands: a cross-modality investigation
Event Information:
The complexity of radiotherapy techniques for treating head and neck cancer has significantly advanced over the previous two decades. However, it remains common for patients to finish treatment with a severe loss in salivary function, causing significantly diminished quality of life assessments. The overall goal of research endeavours in this thesis is to develop innovative techniques that lead to better understanding and consideration of salivary glands during head and neck radiotherapy planning. This goal is approached along a multitude of paths using a variety of imaging modalities and treatment planning techniques.
A method is demonstrated for enhancing prostate specific membrane antigen (PSMA) positron emission tomography (PET) images and intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) using neural networks. PSMA PET shows high expression in salivary glands, and its relationship with functional importance can be more accurately assessed after image enhancement. IVIM MRI is a promising diffusion protocol for investigating functional heterogeneity in salivary glands, but suffers from poor reproducibility. Image enhancement methods and a new model-independent approach to quantifying diffusion are shown to improve the utility, and potentially the reproducibility, of IVIM MRI.
PSMA PET uptake heterogeneity in parotid glands is quantified, demonstrating a consistent bias towards lateroposterior aspects. Uptake patterns are compared with four literature-models of subregional parotid gland importance, revealing an anticorrelation between PSMA PET uptake and relative importance. A model is developed for predicting subregional importance using PSMA PET / computed tomography (CT) radiomic features. A method for tailoring importance estimates using patient-specific data is presented.
An autosegmentation methodology is created for localizing the newly discovered ’tubarial' salivary glands on CT images. This is necessary for consideration of tubarial glands during treatment planning as tubarial glands are only known to be visible on PSMA PET which is not typically acquired for head and neck cancer patients. Ground truth tubarial gland contours were defined using registered PSMA PET images.
Lastly, a technique for translating subregional parotid gland importance data into spatially varying dose constraints during radiotherapy treatment planning is demonstrated. A retrospective planning study showed improvements in predicted salivary output at one year post-radiotherapy using this method.
Event Location:
https://ubc.zoom.us/j/4747189913?pwd=RHEvdjJ3NWU3TTVCdkZGdHVsWlpOQT09&omn=64712444179 Passcode: 123
Event Time:
Monday, January 8, 2024 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
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2024-01-08T16:00:00
2024-01-08T17:00:00
It's Raining Black Holes...Hallelujah!
Event Information:
Abstract:
Gravitational wave (GW) emissions from extreme-mass-ratio inspirals (EMRIs) are promising sources for low-frequency GW detectors.
EMRIs are the result of a supermassive black hole (SMBH) that captures a stellar-mass compact object, such as BH. The channel often considered in the literature involves weak two-body kicks from the population of stars and compact objects surrounding the SMBH that can change the BH's orbit over time, driving it into the SMBH. On the other hand, perturbations from SMBH companions via the eccentric Kozai-Lidov (EKL) mechanism can excite the SMBH to high eccentricities, thereby forming EMRIs.
In this talk, I will demonstrate that combining these two processes is essential to comprehending the dynamics of EMRI progenitors. I will also show that EMRIs are naturally formed in SMBH binaries with higher efficiency than either of these processes considered alone. Thus, it is truly raining black holes! This scenario results in a large stochastic background for future GW detectors such as LISA. Finally, I will demonstrate the implications that this physical mechanism has on tidal disruption events.
Bio:
My group and I are working on a wide range of dynamics research problems covering topics from cosmology to the dynamics of black holes, stars, and extrasolar planets. During my PhD I studied the formation, evolution and properties of the first generations of galaxies and 21cm fluctuations. In parallel, while still a graduate student, I was intrigued by the theoretical challenges and problems in the dynamics of our solar and extra-solar planetary systems and decided to pursue those as well. This part of my work was further enhanced during my postdoc years where I have studied the dynamical evolution of Hot Jupiters. Most notably I have found a new mechanism that, not only produces Jupiter like planets in a very close proximity to the star, but can also explain the eccentric and even retrograde observed systems. This mechanism, known as the Eccentric Kozai-Lidov (EKL) mechanism, raises many interesting research questions, which are applicable to a diverse range of astrophysical systems at different scales.
My group and I continue to work on the formation of structure in the early Universe. Notably, we recently showed that gas-only structures could naturally form without dark matter in the early Universe, at the presence of the supersonic, relative velocity between the gas and dark matter. We showed that these Supersonically-induced gas objects (SIGOs) might be linked to present-day globular clusters.
Learn More:
Read Smadar's faculty website at UCLA: Smadar Naoz (ucla.edu)
Event Location:
HENN 318
Event Time:
Thursday, December 7, 2023 | 4:00 pm - 5:00 pm
Event Location:
HENN 202
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2023-12-07T16:00:00
2023-12-07T17:00:00
Sexualized Violence and Academia Workshop
Event Information:
About:
This workshop provides foundational knowledge of sexual assault and consent, and explores social, cultural, and institutional factors that facilitate sexualized violence. This workshop provides participants with knowledge about what causes, maintains, and constitutes a culture accepting of sexualized violence. We examine the norms which uphold and normalize power, and discuss ways we can address the effects of it through centering a culture of consent. This workshop also explores the facts and realities of sexual harassment and sexual assault and how it can show up in the workplace.
Learn More
https://www.amssasc.ca/
Event Location:
HENN 202
Event Time:
Thursday, December 7, 2023 | 10:00 am - 11:00 am
Event Location:
BRIM 311
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2023-12-07T10:00:00
2023-12-07T11:00:00
Magnetism and superconductivity in rhombohedral graphene multilayers: triplet superconductivity, intervalley coherence, and spin orbit coupling
Event Information:
Abstract: The electronic band structure of rhombohedral graphene multilayers hosts van Hove singularities at which the single particle of states diverges. I will discuss experiments in which we use electrostatic gates to tune the chemical potential through these singularities, revealing a cascade of correlated electron phases; notably, both singlet and triplet superconductors are observed proximal to or within generalized ferromagnetic phases where the system spontaneously polarizes into one or more of the spin- and valley isospin flavors. I will give an overview of this system, and describe recent experiments that reveal the role of intrinsic spin orbit coupling in graphene.
Speaker Bio: Dr. Andrea Young is a professor of Physics at the University of California Santa Barbara. His lab, the Young lab, combines nanofabrication and electronic measurement techniques in order to investigate the properties of electronic states in quantum materials, and is currently interested in the interplay between symmetry, topology, and correlations in low dimensional systems.
Event Location:
BRIM 311
Event Time:
Wednesday, December 6, 2023 | 3:00 pm - 4:00 pm
Event Location:
Hennings 318
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2023-12-06T15:00:00
2023-12-06T16:00:00
Fundamental Physics via Gravitational-Wave Observation
Event Information:
Abstract:
I will review constraints on fundamental physics that have been inferred from observations of gravitational waves, and look forward to see what new results might be obtained in the near future, and what might be possible with future generations of gravitational-wave detectors.
Event Location:
Hennings 318
Event Time:
Monday, December 4, 2023 | 4:00 pm - 5:00 pm
Event Location:
HENN 318
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2023-12-04T16:00:00
2023-12-04T17:00:00
The chaotic lives of planetary systems
Event Information:
Abstract:
Not long after discovering the universal law of gravitation, Isaac Newton asked a troubling question. Is the solar system stable? It took over 300 years to arrive at an answer. Brute-force numerical integrations have demonstrated that it is possible that Mercury will collide with Venus or be lost into the Sun. Yet despite extensive effort on this thorny question, which led to the development of perturbation theory, the discovery of chaos, and the establishment of the field of non-linear dynamics, we still do not understand the physics driving these instabilities in a general context.
This problem has renewed relevance today, since we think such instabilities have shaped the orbital architectures of the thousands of exoplanet systems in the observed sample. I will present recent successes using machine learning techniques to make accurate predictions of long-term stability in compact exoplanetary systems, and discuss how we ultimately used our machine learning models to elucidate the underlying dynamics and arrive at an analytical understanding of the problem.
Event Location:
HENN 318
Event Time:
Thursday, November 30, 2023 | 4:00 pm - 5:00 pm
Event Location:
HENN 202
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2023-11-30T16:00:00
2023-11-30T17:00:00
The Atomic Nucleus as a Window to New Physics
Event Information:
Abstract:
What is the mass of the neutrino? Why is there an abundance of matter over antimatter in our universe? And what is dark matter? Strangely enough, answers might very well lie, yet undiscovered, in impossibly rare nuclear decays, infinitely subtle wobblings of nuclei embedded in radioactive molecules, or the faintest recoils of nuclei colliding with dark matter.
As the role of atomic nuclei in unraveling such fundamental mysteries continues to deepen, first principles quantum simulations, starting from only underlying nuclear and weak forces, are currently undergoing nothing short of a revolution. In this talk I will outline this modern "ab initio" approach to nuclear theory and spotlight several recent milestones, including statistical predictions of the limits of existence and the neutron skin of 208Pb to constrain neutron star properties. Parallel advances also allow first predictions crucial for searches for physics beyond the standard model: neutrinoless double beta decay, dark matter scattering, and symmetry violating moments, with quantifiable uncertainties, for most nuclei relevant for such searches.
Bio:
My research is focused on first-principles calculations of atomic nuclei across all mass regions. I am particularly interested in linking ongoing developments of two and three-nucleon forces rooted in QCD with nuclear structure issues at and beyond the experimental frontiers, such as determining the limits of existence of matter and the evolution of magic numbers towards these limits. Furthermore this work has deep connections to some of the most compelling unanswered questions in beyond-standard-model physics. For instance neutrinoless double beta decay can provide a direct path to knowledge of neutrino masses, WIMP-nucleus scattering may lead to understanding the nature of dark matter, and particular nuclear transitions provide insights into physics at the electroweak scale and beyond. Since these methods are quite general, they can also be broadly extended to other many-body problems such as atomic systems.
Learn More:
See Jason's TRIUMF webpage here
Read his publications here
Event Location:
HENN 202
Event Time:
Thursday, November 30, 2023 | 2:00 pm - 4:30 pm
Event Location:
Henn 309
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2023-11-30T14:00:00
2023-11-30T16:30:00
Quantum Chaos in Conformal Field Theories
Event Information:
Understanding quantum chaos in conformal field theories is extremely important. Chaotic dynamics can explain why so many systems can be studied with statistical mechanics, and why systems reach ``typical’’ states so quickly. Outside of the simplest, highly symmetric systems, all systems are expected to be described by chaotic dynamics; whether and how these dynamics can appear in theories with conformal symmetry is thus essential to further our understanding of most CFTs. Moreover, the AdS/CFT correspondence suggests that chaotic CFTs are important for understanding black holes, which themselves are chaotic systems.
However, the highly symmetric structure of these systems can tend to hide the underlying chaotic behaviour; this unique structure requires us to find the right language and diagnostics for discussing chaotic phenomenon. In this thesis we make significant progress to this end: we demonstrate the part of the energy spectrum that is unconstrained by symmetry and displays chaotic behaviour; we study the link between quantum chaos and the strange properties of ``arithmetic chaos''; we create an effective field theory for analyzing chaotic behaviour and its link to standard CFT technology; and we analyze CFTs with a boundary and their AdS/CFT dual, which have been used to model chaotic black holes.
Event Location:
Henn 309