Events at Physics |
Events During the Week of November 23rd through November 29th, 2025
Monday, November 24th, 2025
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Title to be announced
- Time: 12:00 pm
- Place: 2241 Chamberlin Hall
- Speaker: Valerian Hall-Chen and Mike Zarnstorff, A*Star and PPPL Emeritus
- Host: Cary Forest
- Theory Seminar (High Energy/Cosmology)
- Challenging the standard neutrino sector from cosmology
- Time: 1:00 pm - 2:30 pm
- Place: Chamberlin 5280
- Speaker: Toni Bertólez-Martínez, University of Wisconsin-Madison
- Abstract: As a new postdoc in the department, I will introduce my research around cosmological neutrinos. In the first part of the talk, I will focus on the physical effects that neutrino masses have in cosmological observables, which allow cosmology to place the most stringent bounds on neutrino masses as of today. Then, I will show how CMB bounds can be relaxed not only by a different assumption on the cosmological model, but by non-standard properties of the neutrino sector. This motivates a novel framework which allows to quantify which properties of neutrinos in cosmology we are actually measuring. In the second part of the talk, I will introduce a model which could explain the origin of neutrino masses by a coupling to ultralight dark matter (ULDM). I will introduce a consistent treatment of the coupled neutrino-UDLM oscillations and use Big Bang Nucleosynthesis to put competitive bounds on neutrino-ULDM interactions. This talk is based in 2411.14524 and 2509.22867, respectively.
- Host: Joshua Foster
- Thesis Defense
- First ionization potentials of Cr, Mo, and W calculated with SHCI
- Time: 1:00 pm - 3:00 pm
- Place: B343 Sterling
- Speaker: Zachary Jerzyk, Physics Graduate Student
- Abstract: The design and performance of future fusion power plants will depend on accurate atomic data for plasma-facing material and plasma impurity species. A leading candidate for the plasma-facing material is tungsten due to its high melting point, however, the energy levels and wavefunctions of high-Z atoms with many electrons (e.g. 30 or more), including tungsten, are difficult to calculate with high accuracy. Gaps and large uncertainties in atomic data for tungsten introduce design and performance uncertainties for a fusion power plant. Specifically, improved atomic data for ionization potential, excited state energies, and collisional excitation rates are needed for the low charge states of atomic tungsten. We aim to address these shortcomings by using the semistochastic heat-bath configuration interaction (SHCI) method, which nearly exactly calculates the energies that can be determined at higher cost with the full configuration interaction. Adding well-motivated approximations to SHCI, including orbital optimization and effective core potentials, we demonstrate good agreement between our calculated first ionization potentials and the best available experimental values for chromium, molybdenum, and tungsten. The efficiency and accuracy achieved in calculating these ionization potentials demonstrates that our SHCI workflow can yield improved electron structure data for ions with many electrons, suggesting that the method could also be useful for collisional processes, such as state-selective charge exchange reactions and electron impact ionization.
- Host: Matthew Otten
Tuesday, November 25th, 2025
- No events scheduled
Wednesday, November 26th, 2025
- No events scheduled
Thursday, November 27th, 2025
- Academic Calendar
- Thanksgiving Recess
- Abstract: *Note: actual end time may vary.* University offices closed. CONTACT: admin@secfac.wisc.edu
Friday, November 28th, 2025
- Academic Calendar
- Thanksgiving Recess
- Abstract: *Note: actual end time may vary.* CONTACT: admin@secfac.wisc.edu
Saturday, November 29th, 2025
- Academic Calendar
- Thanksgiving Recess
- Abstract: *Note: actual end time may vary.* CONTACT: admin@secfac.wisc.edu