Events at Physics |
Events on Thursday, December 4th, 2025
- R. G. Herb Condensed Matter Seminar
- Experiments on Non-equilibrium Josephson Systems in One and Two Dimensions
- Time: 10:00 am - 6:00 pm
- Place: 5310 Chamberlin
- Speaker: Andrew Higginbotham, University of Chicago
- Abstract: Experimental progress in quantum computing has yielded exciting new tools for probing and manipulating superconducting circuits. I will present our recent work on driven behavior of 1D and 2D Josephson junction arrays. In one dimension, we have recently studied the lifetime and dynamics of plasmons, which makes some interesting connections to the physics of one-dimensional quantum liquids and classical nonlinear systems. In two dimensions, I will show our discovery of non-equilibrium microwave radiation and non-equilibrium noise scaling near the superconductor-insulator quantum phase transition.
- Host: Roman Kuzmin
- Thesis Defense
- Measurement of the Three Top Quarks Process with the CMS Detector at the LHC
- Time: 10:00 am - 12:00 pm
- Place: 5280 Chamberlin
- Speaker: Dylan Teague, Physics PhD Graduate Student
- Abstract: This thesis presents the first analysis measuring the three top quark decay process at the Large Hadron Collider. The measurement was performed on events with two same-sign leptons and three or more leptons on data taken by the Compact Muon Solenoid detector during the 2016–2018 data taking period corresponding to 137 fb-1 of data with √𝑠 = 13 TeV. The analysis found the three top process to have an overall significance of 0.182𝜎 and a CLs 95 % upper limit of 28.1 fb. These results were also uses to reinterpret the data to place limits on possible beyond Standard Model physics models that predict enhancements to the three top quark cross-section.
- Host: Kevin Black
- Preliminary Exam
- Spiral Arm–Driven Star Formation in the FIRE Simulations
- Time: 11:00 am - 1:00 pm
- Place: 2532 Sterling
- Speaker: Hannah Woodward
- Abstract: Recent observations have traced the trajectories of nearby star clusters backward in time, revealing that many have converging paths and likely shared common origins. This trend spans clusters across a wide range of ages, providing evidence for sequential star formation. While stellar feedback is often invoked to explain such propagation, the dynamics of spiral arms may also compress gas and trigger new star formation. To explore this mechanism, we searched for signatures of spiral arm–induced star formation in the Feedback In Realistic Environments (FIRE) simulations. We applied the HDBSCAN clustering algorithm to identify groups of star particles with similar positions and velocities within selected regions of a simulated galaxy, and then analyzed their kinematic evolution over time. I will compare the motions of FIRE star particles to the observed trajectories of nearby stellar clusters to investigate whether spiral structure can drive sequential star formation.
- Host: Elena Donghia
- Astronomy Colloquium
- Single-lined Eclipsing Binary Stars: A Stellar Astronomy Multi-Tool
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Dan Stevens, University of Minnesota-Duluth
- Abstract: Precisely and accurately measured stellar properties such as mass and radius are important for a wide range of science cases, from characterizing nearby exoplanets to inferring properties of distant galaxies. Double-lined eclipsing binary stars (DLEBs) have long been the gold standard for making such measurements, as the two similar-luminosity stars’ individual masses and radii can routinely be measured to percent-level precision. By combining space-based observations from the TESS and Gaia space telescopes with archival datasets, it is now possible to measure fundamental stellar parameters precisely and accurately for single-lined EBs (SLEBs), in which only the more luminous star’s spectrum is seen. I will summarize the advantages of studying SLEBs for specific science cases, focusing on recent efforts by my research group and others to resolve the longstanding problem of radius inflation in low-mass stars. I will also highlight a few “superlative” SLEB discoveries and their potential for probing stellar physics across the HR diagram. I will discuss the obstacles we have encountered to characterize SLEBs to percent-level precision and accuracy, then preview the near-term prospects for overcoming them.
- Host: Nicholas Stone