Events at Physics
Events on 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