Events at Physics |
Events During the Week of January 24th through January 31st, 2021
Monday, January 25th, 2021
- Academic Calendar
- Instruction begins
- Abstract: *Note: actual end time may vary.*
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Status and progress in the domestic liquid metal plasma-facing component design program
- Time: 12:00 pm
- Place: Zoom Meeting
- Speaker: Rajesh Maingi and Andrei Khodak, PPPL
- Abstract: Chris Hegna is inviting you to a scheduled Zoom meeting.
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Meeting ID: 918 3541 9103
Passcode: 578475
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Meeting ID: 918 3541 9103
Passcode: 578475 - Host: Chris Hegna
- Monday Science Seminar
- Monday Science Seminar w/ Dr. Robert Benjamin (University of Wisconsin - Whitewater)
- Time: 12:00 pm - 1:00 pm
- Place:
- Speaker: Dr. Robert Benjamin, University of Wisconsin - Whitewater
- Abstract: “A Thirty Degree Ionized Circular Arc Around the Big Dipper…and Other Surprises”
Abstract: I describe the discovery of a faint (1 Rayleigh) thirty-degree circular arc of ionized gas centered on the handle of the Big Dipper: the Ursa Major Arc. The arc subtends one radian of a circle of angular diameter 60 degrees, is detected in both H-alpha and diffuse ultraviolet emission and is one of the most unusual objects in the sky. I compare this object to other recently discovered large angular size supernova remnants and describe the significance of these objects. If time allows, I will share some other recent discoveries of ionized gas structures in the Milky Way. - Host: Snezana Stanimirovic & Melinda Soares-Furtado
Tuesday, January 26th, 2021
- Council Meeting
- Physics Council
- Time: 4:00 pm - 5:00 pm
- Place:
- Host: Sridhara Dasu
Wednesday, January 27th, 2021
- Physics ∩ ML Seminar
- The Importance of Being Interpretable
- Time: 11:00 am - 12:15 pm
- Place: Online Seminar: Please sign up for our mailing list at www.physicsmeetsml.org for zoom link
- Speaker: Michelle Ntampaka, Space Telescope Science Institute
- Abstract: Cosmology is entering an era of data-driven science. Modern machine learning techniques are being combined with large astronomical surveys to enable powerful new research methods. This shift in our scientific approach requires us to ask an important question: Can we trust the black box? I will present a deep machine learning approach to constraining cosmological parameters with multi-wavelength observations of galaxy clusters. The ML approach has two components: an autoencoder that builds a compressed representation of each galaxy cluster and a flexible CNN to estimate the cosmological model from a cluster sample. From mock observations, the ML method estimates the amplitude of matter fluctuations, sigma8, at approximately the expected theoretical limit. More importantly, the deep ML approach can be understood and interpreted. I will lay out three schemes for interpreting the ML technique: a leave-one-out method for assessing cluster importance, an average saliency for evaluating feature importance, and correlations in the terse layer for understanding whether an ML technique can be safely applied to observational data. I will introduce the term “overspecialized" to describe a common pitfall in astronomical applications of machine learning in which the ML method learns simulation-specific details, and we show how a carefully sculpted architecture can be used to check for this source of systematic error.
- Host: Gary Shiu
- Department Meeting
- Department Meeting - CANCELLED
- Time: 12:15 pm - 1:15 pm
- Place: CANCELLED due to lack of urgent business.
- Speaker: Sridhara Dasu, Department Chair
- Cancelled due to lack of urgent business.
- Host: Sridhara Dasu
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Exploring Galaxy Evolution from Radio Observations
- Time: 4:00 pm - 5:00 pm
- Place: Virtual
- Speaker: Hansung Gim, Arizona State University
- Abstract: Zoom info
Meeting ID: 93592708053, passcode: cmbadger
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- Host: Keith Bechtol
Thursday, January 28th, 2021
- Astro Tool Exchange
- High Dimensional Data Visualization with Glue
- Time: 10:00 am - 11:00 am
- Place:
- Speaker: Cameren Swiggum, University of Wisconsin - Madison
- Abstract: This is an informal one-hour meeting with rotating hosts. For this first installment, UW-Madison graduate student Cameren Swiggum will talk about how he uses Glue (with WorldWide Telescope) in his research workflow.
Come prepared to learn in real-time, ask questions, and *hopefully* walk away with a handy new tool in your toolbox.
Want to know more about Glue? In the link below, Chris Beaumont provides a useful walkthrough of the Glue platform at the 2013 SciPy conference:
Feel free to download the software prior to the meeting if you'd like to try it out beforehand.
Glue installation:
Want to see your favorite tool on the Astro Tool Exchange roster? Fill out the poll below. Add missing tools using the "other" feature. The current poll results are attached (as crowd sourced on Twitter).
- Host: Melinda Soares-Furtado
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- A Quick Look at the 3GHz Radio Sky: Early Continuum Science from the VLA Sky Survey
- Time: 12:00 pm - 1:00 pm
- Place: Virtual
- Speaker: Yjan Gordon, University of Manitoba
- Abstract: Zoom info
Meeting ID: 93592708053, passcode: cmbadger
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- Host: Keith Bechtol
- Astronomy Colloquium
- "Spatially Resolved Galaxy Interactions
- Time: 3:30 pm - 5:00 pm
- Place: Zoom meeting Coffee and tea 3:30pm, Talk 3:45 PM
- Speaker: Jorge Moreno, Pomona College
- Abstract: For decades, late-stage galaxy mergers have been recognized as naturally occurring events within the hierarchical LCDM paradigm, capable of triggering starburst and quasars. Early-stage mergers (interactions), albeit not as dramatic as their late-stage counterparts, are believed to shape galaxies in gentler and more long-lasting ways: by enhancing star formation, suppressing gas metallicity, igniting AGNs, augmenting H2 fuel, etc. But more importantly, their cumulative effect may ultimately stimulate the transformation of spirals into lenticulars in dense environments. The focus of this talk is to address the spatial structure and evolution of star formation and the interstellar medium (ISM) in interacting galaxies. We use an extensive suite of parsec-scale galaxy merger simulations (stellar mass ratio = 2.5:1), which employs the "Feedback In Realistic Environments-" model (FIRE-2). This framework resolves star formation, feedback processes, and the multi-phase structure of the ISM. We focus on the galaxy-pair stages of interaction. We find that close encounters substantially augment cool (HI) and cold-dense (H2) gas budgets, elevating the formation of new stars as a result. We also find that galaxies with elevated global star formation rate (SFR) experience intense nuclear SFR enhancement, driven by high levels of either star formation efficiency (SFE) or available cold-dense gas fuel. Galaxies with suppressed global SFR also contain a nuclear cold-dense gas reservoir, but low SFE levels diminish SFR in the central region. Our numerical predictions underscore the need of substantially larger, and/or merger-dedicated, spatially-resolved (integral-field spectroscopic) galaxy surveys -- capable of examining vast and diverse samples of interacting systems -- coupled with multi-wavelength campaigns aimed to capture their internal ISM structure. Zoom Link:
- Host: Melinda Soares-Furtado
Friday, January 29th, 2021
- Theory Seminar (High Energy/Cosmology)
- A physical protocol to obtain information in quantum gravity
- Time: 2:00 pm - 3:00 pm
- Place: For zoom link, sign up at:
- Speaker: Chandramouli Chowdhury, ICTS, Bangalore
- Abstract: We consider a set of observers who live near the boundary of global AdS, and are allowed to act only with simple low-energy unitaries and make measurements in a small interval of time. The observers are not allowed to leave the near-boundary region. We describe a physical protocol that nevertheless allows these observers to obtain detailed information about the bulk state. This protocol utilizes the leading gravitational back-reaction of a bulk excitation on the metric, and also relies on the entanglement-structure of the vacuum. For low-energy states, we show how the near-boundary observers can use this protocol to completely identify the bulk state. We explain why the protocol fails completely in theories without gravity, including non-gravitational gauge theories. This provides perturbative evidence for the claim that one of the signatures of holography -- the fact that information about the bulk is also available near the boundary -- is already visible in semiclassical gravity. This is work done in collaboration with Olga Papadoulaki and Suvrat Raju, in 2008.01740.
- Host: Lars Aalsma
- Atomic Physics Seminar
- Quantum simulation of spin models with tunable arrays of 200 single Rydberg atoms
- Time: 2:00 pm
- Place:
- Speaker: Thierry Lahaye, Université Paris Saclay & CNRS, Palaiseau
- Abstract: In this seminar, I will present how arrays of up to 200 single atoms held in optical tweezers and made to interact by exciting them to Rydberg states are an almost ideal platform for quantum simulation of quantum magnetism. I'll first review briefly the experimental realization of such arrays, and then illustrate, with recent experiments, how we can use it simulate the behavior of Ising or XY quantum magnets.
Please note that the old VAMOS Zoom link from prior seminars will no longer work. This seminar (and future seminars) can be accessed via the links on our website (https://sites.google.com/stanford.edu/virtual-amo-seminar/home) or this new Zoom link ( ).
There will also be a post-seminar discussion session with the speaker. The discussion will take place in a separate Zoom room directly after the seminar, and all attendees are welcome to participate. (Faculty will be asked to leave after ~10-15 minutes to give students and postdocs more opportunities to interact with the speaker.)
- Department Coffee Hour
- Department Coffee Hour (Virtual)
- Time: 3:30 pm - 4:30 pm
- Place: Virtual (see abstract for connection info)
- Abstract: Topic: Department Coffee Hour
Time: Jan 29, 2021 03:30 PM Central Time (US and Canada)
Every week on Fri, until May 14, 2021, 16 occurrence(s)
Jan 29, 2021 03:30 PM
Feb 5, 2021 03:30 PM
Feb 12, 2021 03:30 PM
Feb 19, 2021 03:30 PM
Feb 26, 2021 03:30 PM
Mar 5, 2021 03:30 PM
Mar 12, 2021 03:30 PM
Mar 19, 2021 03:30 PM
Mar 26, 2021 03:30 PM
Apr 2, 2021 03:30 PM
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Apr 16, 2021 03:30 PM
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Apr 30, 2021 03:30 PM
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May 14, 2021 03:30 PM
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Join Zoom Meeting
Meeting ID: 979 8528 1970
Passcode: 309601
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+13126266799,,97985281970#,,,,*309601# US (Chicago)
+19292056099,,97985281970#,,,,*309601# US (New York)
Dial by your location
+1 312 626 6799 US (Chicago)
+1 929 205 6099 US (New York)
+1 301 715 8592 US (Washington D.C)
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Meeting ID: 979 8528 1970
Passcode: 309601
Find your local number:
Join by SIP
97985281970@zoomcrc.com
Join by H.323
162.255.37.11 (US West)
162.255.36.11 (US East)
115.114.131.7 (India Mumbai)
115.114.115.7 (India Hyderabad)
213.19.144.110 (Amsterdam Netherlands)
213.244.140.110 (Germany)
103.122.166.55 (Australia)
149.137.40.110 (Singapore)
64.211.144.160 (Brazil)
69.174.57.160 (Canada)
207.226.132.110 (Japan)
Meeting ID: 979 8528 1970
Passcode: 309601
- Host: Climate and Diversity Committee