Events at Physics |
Events During the Week of October 19th through October 26th, 2025
Monday, October 20th, 2025
- Theory Seminar (High Energy/Cosmology)
- Non-linear sigma model in string field theory
- Time: 1:00 pm - 2:30 pm
- Place: Chamberlin 5280
- Speaker: Manki Kim, Stanford University
- Abstract: I will describe how to construct data of the worldsheet CFT of the strings probing a curved background with a non-trivial topology in string field theory. As a simple application, I will describe how to use this result to compute the D-instanton superpotential and loop corrections to the Kahler potential in Calabi-Yau orientifold compactifications in the large volume limit. Event recording:
- Host: Jakob Moritz
Tuesday, October 21st, 2025
- Mathematica Office Hour
- Time: 9:15 am - 10:15 am
- Place: 4272 Chamberlin
- Speaker: Jeff Weidenaar, Wolfram
- Abstract: New to Mathematica? Have a specific question? Want to see how AI can help you code faster and better? Drop by Room 4272 from 9:15-10:15 on Tuesday, Oct 21 to learn from Wolfram trainer Jeff Weidenaar.
- Host: Dan Bradley
- Council Meeting
- Physics Council Meeting
- Time: 3:00 pm - 4:00 pm
- Place: 2314 Chamberlin
- Speaker: Kevin Black, UW - Madison
- Host: Kevin Black
- Wonders of Physics
- WhySci Variety Show
- Time: 7:00 pm - 9:00 pm
- Place: Majestic Theatre, 115 King Street
- Speaker: Haddie McLean
- Abstract: The Wonders of Physics will be a part of this high-energy mashup of science talks, artful performances, and live music! This year’s theme is Rock and Roll, so expect brainy beats, geology jokes, and scientific showmanship that will have you thinking and tapping your toes.
Wednesday, October 22nd, 2025
- Department Meeting
- Time: 12:15 pm - 1:15 pm
- Place: B343 Sterling
- Speaker: Kevin Black, UW-Madison
- Host: Kevin Black
Thursday, October 23rd, 2025
- R. G. Herb Condensed Matter Seminar
- Multi-Partite Entanglement and Spectral Witness in Quantum Materials
- Time: 10:00 am - 6:00 pm
- Place: 5310 Chamberlin
- Speaker: Yao Wang, Emory University
- Abstract: The rapidly advancing field of quantum materials demands increasingly precise methods for characterizing and controlling entanglement. While early progress was made in quantum optics, extending these approaches to complex many-body systems in quantum materials remains a major challenge. In this talk, I will introduce the entanglement witness framework for characterizing the bounds of entanglement depth using solid-state spectroscopies. In the first half of the talk, I will begin with the detection of spin entanglement in quantum magnets through the quantum metrology and spin quantum Fisher information (QFI). These metrics can be accessed via inelastic neutron scattering and resonant inelastic x-ray scattering (RIXS). Importantly, RIXS provides a route to extend such probes far out of equilibrium, enabling the control of entanglement with light. In the second half of the talk, I will move beyond entanglement among distinguishable local modes to explore entanglement in systems of indistinguishable fermions. I will present a generalized framework for multi-particle entanglement among electrons, based on the cumulant reduced density matrix and the nonlinear response characteristics of RIXS.
- Host: Ilya Esterlis
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Multimessenger Probes of High-Energy Neutrino Production in AGN and Microquasars
- Time: 2:30 pm - 3:30 pm
- Place: Chamberlin 5280
- Speaker: Jose Carpio, University of Nevada
- Abstract: The discovery of astrophysical neutrinos by the IceCube Neutrino Observatory established neutrinos as a new messenger, opening a window to the most extreme particle accelerators in the Universe. Created in hadronic interactions, high-energy neutrinos are necessarily co-produced with γ-rays. The detection of neutrinos from NGC 1068, without accompanying γ-rays, thus reveals production in γ-ray–opaque environments, pointing to dense AGN cores as powerful accelerators. Meanwhile, IceCube's observation of Galactic neutrinos has opened a new front in understanding the sources of cosmic rays. Recent HAWC and LHAASO detections of >100 TeV γ-rays from microquasars such as SS 433 and V4641 Sgr show that compact binaries can also accelerate particles to high energies. This observation motivates targeted neutrino searches to determine whether the γ-rays are leptonic or hadronic in nature. In this talk, I will use the measured AGN neutrino spectra and γ-ray data to constrain source models and their contribution to the isotropic neutrino flux. In addition, I will use the γ-ray and X-ray data from SS 433 and V4641 Sgr to predict their neutrino fluxes from a hadronic component and assess their detection prospects with current and next-generation neutrino detectors.
- Host: Lu Lu
- Astronomy Colloquium
- Precise Stellar Properties via Bayesian Analysis of Stellar Evolution
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Prof. Ted von Hippel, Embry-Riddle Aeronautical University
- Abstract: While it is well known that astronomers can use stellar models to infer the ages of open and globular clusters, as well as populations of white dwarfs, what is often not appreciated is that with precision astrometry and photometry, we can frequently infer the ages of individual stars. Individual stellar ages are themselves valuable, for instance for exoplanet host stars, and these individual stellar ages can be aggregated for stellar population studies. I will discuss our Bayesian approach to comparing stellar evolution models to data to infer stellar ages, and also speak briefly about how this approach can be used to derive highly precise stellar cluster properties, infer binary mass ratios, and even study multi-component globular clusters. My group’s BASE-9 code, upon which this work is based, is open-source and available on GitHub, and for those interested in incorporating it into their research, we are happy to provide training and support.
- Host: Nicholas Stone
Friday, October 24th, 2025
- Physics Department Colloquium
- Skyrmion Textures in Magnetic Materials
- Time: 3:30 pm - 4:30 pm
- Place: Chamberlin 2241
- Speaker: Cristian Batista, University of Tennessee, Knoxville
- Abstract: Building on Hermann von Helmholtz’s ideas, William Thomson proposed in 1867 that atoms could be vortices in the aether. Although later experiments dismissed this notion, the idea of topological solitons as fundamental or artificial atoms remains compelling. Since the 1960s, evidence has mounted for modern analogues to the aether concept. In quantum magnets, this “aether” takes the form of a vector field of magnetic moments, where topological solitons emerge as mesoscale analogs of atoms. Like real atoms, these solitons arrange themselves into periodic arrays or “crystals,” governed by symmetry, anisotropy, and competing microscopic interactions. These magnetic textures produce an effective magnetic field that, when coupled to the orbital motion of conduction electrons, can reach extreme magnitudes. We will explore how these topological magnetic structures emerge in real materials and how the quantum nature of spins can give rise to a broader range of skyrmion textures, such as the one shown in the figure, extending beyond those observed to date.
- Host: Elio König