Events at Physics |
Events During the Week of November 13th through November 19th, 2022
Monday, November 14th, 2022
- Academic Calendar
- Students begin enrolling for Spring term courses according to their appointment times
- Abstract: *Note: actual end time may vary.* CONTACT: 262-3811, registrar@em.wisc.edu URL:
- GREAT IDEAS DEI Reading Group
- Diversity Forum
- Time: 8:00 am - 7:00 pm
- Place: Online:
- Abstract: Join GMaWiP and others in attending the UW-Madison Diversity Forum!
See schedule of events here:
Register to attend virtually here:
We hope to see you there! - Plasma Physics (Physics/ECE/NE 922) Seminar
- Characterization of Intermittency and Energy Transfer via Three-Wave Coupling in a Turbulent Dipole Plasma
- Time: 12:00 pm - 1:00 pm
- Place: 1610 Engineering Hall
- Speaker: Mel Abler, Space Science Institute
- Abstract: Plasmas confined by a dipole magnetic field exhibit interchange and entropy mode turbulence causing bursty intermittent transport of particles and energy [1]. On the Collisionless Terrella Experiment (CTX), this turbulence is dominated by low-frequency, long-wavelength modes with amplitudes and phases that vary chaotically in time [2]. We present a new paradigm for characterizing this turbulence by measuring the time-evolution of the fluctuation power spectrum and the instantaneous bispectrum using the continuous wavelet transform [3,4] and computing the statistical properties of turbulent wave kinetics. We observe that both the fluctuation power and the energy transfer by three-wave coupling, or bispectrum, between these fluctuations can be intermittent. When antenna are used to actively launch waves into the turbulence, the intermittency of the driven waves decreases, while the intermittency of other waves increases. Similarly, application of active feedback [5] to amplify the turbulence decreases the intermittency of the wave energy, while suppressing feedback increases this intermittency. Measurements based on this new paradigm show that the transfer of wave energy to larger and smaller scales in a turbulent plasma is not steady but occurs in short and intense bursts, analogous to the better-known short bursts of particle transport in magnetized plasma.
[1] B.A. Grierson, et al, Phys Rev Lett 105, 205004 (2010).
[2] B.A. Grierson, et al, Phys Plasmas 16, 055902 (2009).
[3] C. Torrence and G.P. Compo, Bulletin of the American Meteorological Society, 61-78 (1998).
[4] B.P. Van Milligen, et al, Phys Rev Lett 74, 395 (1995).
[5] T.M. Roberts, et al, Phys Plasmas 22, 055702 (2015).
Bio: Mel Abler is a Postdoctoral Research Associate at the Space Science Institute focused on experimental studies of the nonlinear behavior of Alfven waves. They recently completed their doctoral work characterizing turbulent wave kinetics and energy transfer via three-wave coupling in a dipole-confined plasma at Columbia University. Mel is a passionate advocate for improving inclusion in physics, and currently serves as the Secretary-Treasurer of the APS DPP Pride Committee. Outside the lab, Mel is an avid theater goer, union organizer, and competitive rower. - Host: Plasma Physics Group
Tuesday, November 15th, 2022
- GREAT IDEAS DEI Reading Group
- Diversity Forum
- Time: 8:00 am - 7:00 pm
- Place: Online:
- Abstract: Join GMaWiP and others in attending the UW-Madison Diversity Forum!
See schedule of events here:
Register to attend virtually here:
We hope to see you there! - Theory Seminar (High Energy/Cosmology)
- Constraining the CP character of the Higgs-fermion interactions
- Time: 4:00 pm - 5:00 pm
- Place: Chamberlin 5280
- Speaker: Henning Bahl, U. Chicago
- Abstract: The CP structure of the Higgs boson in its coupling to the particles of the Standard Model is amongst the most important Higgs boson properties which have not yet been constrained with high precision. In this talk, I will explain how existing inclusive and differential Higgs boson measurements from the ATLAS and CMS experiments can be used to constrain the CP nature of the Higgs-fermion interactions. Moreover, I will show how machine-learning-based inference can be used to tighten these constraints in the future by exploiting the full kinematic information. At the end of the talk, I will discuss the constraints arising from the measurement of the electron EDM and discuss how much CP violation in the Higgs sector can contribute to the baryon asymmetry of the Universe.
- Host: George Wojcik
Wednesday, November 16th, 2022
- Physics ∩ ML Seminar
- Anomaly detection in the search for new physics
- 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: Gregor Kasieczka, Hamburg University
- Abstract: Given the absence of new physics discovered in direct searches at colliders, new strategies revolving around the use of machine learning to discover anomalous events in data are increasingly proposed and carried out. This talk will discuss how such anomaly detectors can be trained in a data-driven way, what key challenges are, and how they can be overcome.
- Host: Gary Shiu
- GREAT IDEAS DEI Reading Group
- GREAT IDEAS DEI coffee hour
- Time: 12:15 pm - 1:15 pm
- Place: Chamberlin 5280 or online at
- Abstract: We will be discussing this article, Do introductory courses disproportionately drive minoritized students out of STEM pathways? We are asking people to focus on the abstract, significance statement, future work, and conclusions. We also welcome attendees who have not had a chance to read the article.
GREAT IDEAS stands for Group for Reading, Educating, And Talking about Inclusion, Diversity, Equity, & Advocacy in Science. It is a multimedia reading group dedicated to amplifying the experiences of underrepresented groups in science and academia in order to become better advocates for our peers. GREAT IDEAS is open to everyone (students/ faculty/ staff/ etc), and all are welcome and encouraged to engage with the material and contribute to the discussions. To keep a welcoming and safe environment for everyone, we ask that everyone understand and adhere to our community guidelines for the discussions. If you would like to submit an article for a future GREAT IDEAS discussion, you can do so on this form. - Host: GMaWiP and Climate and Diversity Committee (contact Jessie Thwaites or Mallory Conlon with questions)
Thursday, November 17th, 2022
- R. G. Herb Condensed Matter Seminar
- Local observables and Loschmidt echo of quenched paired fermionic superfluids
- Time: 10:00 am - 6:00 pm
- Place: 5310 Chamberlin
- Speaker: Victor Gurarie, UC Boulder
- Abstract: We describe time evolution of quenched paired fermionic s-wave and p-wave superfluids. After reviewing some of the more established results concerning the steady states they reach after the quench, we discuss their Loschmidt echo. We demonstrate that conventional mean field theory calculates classical echo instead of its quantum counterpart, and show how it should be modified to capture the full quantum Loschmidt echo. We use these results to show that the Loschmidt echo of topological p-wave superconductors feature singularities periodically occurring in time, while the Loschmidt echo of non topological s-wave superconductors is free of singularities.
- Host: Maxim Vavilov
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Boosted Higgs and the Effective Field Theory
- Time: 2:30 pm - 3:30 pm
- Place: 4274 Chamberlin Hall
- Speaker: Nick Smith, Fermilab
- Abstract: Recent developments in jet substructure allow novel measurements of Higgs boson production at high transverse momentum. I will discuss these measurements, done in CMS, and how they can be effective indirect probes of new physics through the Standard Model Effective Field Theory (SMEFT) formalism. I will then present prospects for global combinations within SMEFT, and the computational tools being developed to enable them.
- Host: Kevin Black
- Astronomy Colloquium
- Introducing TIGRESS-NCR: current status of numerical modeling of the star-forming ISM
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Dr. Chang-Goo Kim, Princeton University
- Abstract: The importance of star formation “feedback” to the energetics of the interstellar medium (ISM) has been appreciated throughout the modern history of astronomy. Star formation is inefficient in gas consumption because feedback efficiently maintains the pressure support against gravity, which is otherwise rapidly lost via cooling and turbulence dissipation. At the same time, collective actions of feedback drive galactic-scale outflows, controlling the baryonic cycle in galaxy halos. In this talk, I will introduce the TIGRESS framework and its non-equilibrium cooling and radiation (NCR) extension. We solve magneto-hydrodynamics equations in a local shearing box representing a patch of galactic disks to take advantage of limited outer dimensions (~kpc) to achieve uniformly high resolution (~pc). The TIGRESS-NCR framework synthesizes our current best knowledge on governing physics of the star-forming ISM, including supernova and UV radiation feedback as well as photochemical reactions associated with UV (and cosmic rays) to set radiative heating rates and abundances for major coolants self-consistently. I will present the first results from a suite of simulations using the TIGRESS-NCR framework and explain the co-regulation of SFRs and the ISM. Specifically, I will delineate the self-regulation of SFRs in the context of pressure-regulated, feedback-modulated star formation theory and ISM phase structure and energetics with detailed breakdowns into energy source/sink from different processes and in different phases. Finally, I emphasize that having such a numerical framework is a departure point for further numerical experiments, including models with spiral arms and at low metallicities.
- Host: Ke Zhang
Friday, November 18th, 2022
- Physics Department Colloquium
- Planning for the unexpected: Science, invention and the art of the possible
- Time: 3:30 pm - 4:30 pm
- Place: Discovery Building
- Speaker: Thomas F. Kelly, Mark Saffman, and Cary Forest
- Abstract: UW-Madison researchers patent hundreds of inventions through WARF every year, but few campus innovators begin their career with that goal in mind. Join us for three stories of science leading to invention. Each is unique. And each led to exciting outcomes for the university, WARF and the researchers. Featuring: · Thomas F. Kelly, Founder and CEO, Steam Instruments; and Honorary Fellow, Department of Materials Science and Engineering · Mark Saffman, Johannes Rydberg Professor of Physics; Director, Wisconsin Quantum Institute; and Chief Scientist for Quantum Information, ColdQuanta · Cary Forest, Prager Professor of Physics; Director, Wisconsin Plasma Physics Lab; and CTO, Realta Fusion
- Host: Mark Eriksson