Events at Physics |
Events During the Week of January 25th through February 1st, 2026
Monday, January 26th, 2026
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Efficiently Learning Linear System Solvers for Fast Numerical Simulation
- Time: 12:00 pm - 1:00 pm
- Place: EH 1227
- Speaker: Professor Misha Khodak , University of Wisconsin-Madison
- Abstract: Accelerating PDE solving is an important emerging AI application, but popular approaches that fully replace classical solvers using neural networks often struggle to compete due to insufficient data, optimization issues, low precision, and a lack of guarantees. We consider the alternative paradigm of integrating learning directly into solvers, focusing specifically on initial value PDEs, for which the main computational cost is often solving a sequence of linear systems. We introduce PCGBandit, a lightweight online learning algorithm that has performance guarantees under practically reasonable distributional assumptions on the linear systems' target vectors, and implement it in the popular open-source software OpenFOAM. In evaluations across six different settings, including two MHD simulations, PCGBandit yields significant wallclock reductions while inheriting the classical solvers' precision and correctness. Lastly, we highlight several future directions for analyzing scientific computing via the lens of learning theory/online algorithms and for further data-driven impact on numerical simulation.
Tuesday, January 27th, 2026
- Council Meeting
- Time: 3:00 pm - 4:00 pm
- Place: 2314 Chamberlin
- Speaker: Kevin Black
- Host: Kevin Black
Wednesday, January 28th, 2026
- Department Meeting
- Time: 12:15 pm - 1:15 pm
- Place: B343 Sterling
- Speaker: Kevin Black, UW - Madison, Department of Physics
- Department Meeting
- Host: Kevin Black
Thursday, January 29th, 2026
- Astronomy Colloquium
- What Are We Learning About Super-Eddington Accretion Disks From Simulations?
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Prof. Chris Fragile, College of Charleston
- Abstract: Accretion of gas onto black holes is one of the most important processes shaping our Universe. Understanding extremely high rates of accretion (dubbed `super-Eddington') is vital to explaining the challenging observation that supermassive black holes (SMBHs) are fully formed at redshifts >7. It is also important to understanding astrophysical objects such as tidal disruption events (TDEs) and ultra-luminous X-ray sources (ULXs). While we are able to perform observations of super-Eddington accreting systems, to understand them more fully, we must turn to numerical studies. In this talk, I will present the results of some recent super-Eddington disk simulations and discuss some of the interesting things we are learning.
- Host: Sebastian Heinz
Friday, January 30th, 2026
- Physics Department Colloquium
- Atomtricity: From Gauge Field Theory to Transistors for Matter Waves
- Time: 3:30 pm - 4:30 pm
- Place: Chamberlin 2241
- Speaker: Dana Z. Anderson, Infleqtion and University of Colorado, Boulder
- Abstract: Gauge fields arise within a rather abstract theoretical framework for addressing interactions among sets of identical particles; it is central particularly to high-energy particle physics and has recently become of interest to the AMO and quantum information physics communities. The canonical electronic transistor is a three-terminal device in which a weak signal can control a much stronger one. The transistor has a central role in nearly all modern electronics products. This talk takes a fast-moving yet scenic path starting with gauge field theory to describe the principles of transistors that operate on (ultracold) atoms rather than electrons. Historically gauge field theory was developed to understand the fundamental particles and forces of nature. Notably, Maxwell’s equations can be derived directly from a gauge field theory that incorporates the speed of light and the impedance of free space as empirical constraints (among a few others). Yet gauge field theory itself is agnostic as to whether particles and forces are or are not fundamental. We have applied it to identical neutral atoms that interact (such as ultracold 87Rb atoms) via van der Waals forces. Imposing the laws of non-relativistic quantum mechanics rather than the laws of Relativity as constraints to the theory leads to a set of matter wave duals to Maxwell’s equations. These ultimately lead to what one might refer to as the “laws of atomtricity” that are duals to the laws of electromagnetism. These laws enable one to define and study the mechanics of AC matter waves, i.e., waves that are associated with alternating particle currents. Their behavior is dramatically different than the more familiar matter waves associated with the time-independent Schrödinger equation. The laws of atomtricity naturally involve the concept of impedance, which concept leads to circuit elements, and particularly to transistors and transistor circuits that can be used to generate AC matter waves. Being an applied physicist, I cannot help but tell you how the new physics and matter wave circuits can be useful.
- Host: Mark Saffman