Events at Physics |
Events During the Week of December 5th through December 12th, 2021
Monday, December 6th, 2021
- No events scheduled
Tuesday, December 7th, 2021
- Network in Neutrinos, Nuclear Astrophysics, and Symmetries (N3AS) Seminar
- Dark lepton superfluid in proto-neutron stars
- Time: 2:00 pm
- Place: Meeting ID: 994 6425 2867
- Speaker: Dake Zhou , University of California, Berkeley and Northwestern University
- Abstract: I will discuss how sub-GeV neutrino portal bosons that carry lepton number can condense inside a proto-neutron star (newly born neutron star). These bosons are produced copiously and form a Bose-Einstein condensate for a range of as yet unconstrained coupling strengths to neutrinos. The condensate is a lepton number superfluid with transport properties that differ dramatically from those encountered in ordinary dense nuclear matter. I will discuss how this phase of matter could alter the evolution of proto-neutron stars and comment on the implications for neutrino signals and nucleosynthesis. Time: December 7, 2021 2:00 PM Meeting ID: 994 6425 2867
- Host: Baha Balantekin
Wednesday, December 8th, 2021
- Physics ∩ ML Seminar
- Genetic algorithms and breeding branes
- Time: 11:00 am - 12:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Gregory Loges, UW Madison
- Abstract: Taking inspiration from nature, genetic algorithms provide an approach to optimization which mimics aspects of natural selection. Breeding, mutation, and ‘survival of the fittest’ all drive a population of individuals, generation by generation, towards their fittest form. In this talk I will present an introduction to genetic algorithms and discuss ongoing work utilizing genetic algorithms to search for consistent intersecting brane models.
- Host: Moritz Muenchmeyer
- Theory Seminar (High Energy/Cosmology)
- The cosmological moduli problem and naturalness
- Time: 1:00 pm - 2:00 pm
- Place: Chamberlin 5280
- Speaker: Robert Wiley Deal, University of Oklahoma and University of Wisconsin-Madison
- Abstract: We examine the cosmological moduli problem and its connection to electroweak naturalness. The cosmological moduli problem (CMP) comes in three parts: 1. Potential violation of Big-Bang nucleosynthesis (BBN) constraints from late decaying moduli fields, 2. The moduli-induced gravitino problem wherein gravitinos are overproduced and their decay violates BBN or dark matter overproduction bounds, and 3. The moduli-induced lightest SUSY particle (LSP) overproduction problem. We calculate the various two-body decay widths of a light modulus field into MSSM particles and gravitinos within general supersymmetric models. We evaluate regions of gravitino mass vs modulus mass parameter space constrained by BBN, by overproduction of gravitinos, and by overproduction of neutralino dark matter, along with connections to naturalness. We introduce a new solution to the CMP, and list a variety of other solutions to the CMP.
- Host: Lars Aalsma
Thursday, December 9th, 2021
- Astronomy Colloquium
- Winds of Change around Black Holes
- Time: 3:30 pm - 5:00 pm
- Place: 4421 Sterling Hall, Coffee and cookies 3:30 PM, Talk begins at 3:45 PM
- Speaker: Greg Sivakoff, University of Alberta
- Abstract: Accretion disks, where matter with angular momentum spirals down through a disk, occur around objects ranging from the youngest stars to supermassive black holes. But not all of this material reaches the center of the disk. Instead, some material is accelerated away from the disk. These outflows can be ejected in a narrow opening angle (what astronomers call "jets") or can be relatively unfocused (what astronomers call “winds”). While we do not know the precise processes that accelerate and collimate winds and jets, magnetic fields almost certainly play a key role. My team and I study black hole X-ray binaries, stellar-mass black holes accreting from a nearby star. We combine observations across the electromagnetic spectrum to learn about the physics of accretion and jets. In this talk, I will discuss how we have revealed two new windows onto the physics of inflows and outflows in X-ray binaries: fast variability measured across the electromagnetic spectrum (which provides the potential to accurately identify the accretion physics that launch relativistic jets) and the modelling of changes in the X-ray brightness of black hole X-ray binaries (which implies that strong winds from the accretion disk are universal). With the advent of new and upcoming facilities, we have a huge potential to take advantage of these winds of change in the next decade.
This will be a version of the lectures I gave in 2020 on the Canadian Association of Physicists Lecture Tour, making it well suited for undergraduates to attend. - Host: Professor Sebastian Heinz
Friday, December 10th, 2021
- Graduate Introductory Seminar (Physics 701)
- Broader impacts through outreach: your key to an NSF fellowship
- Time: 12:05 pm - 12:55 pm
- Place: 2241 Chamberlin
- Speaker: Mallory Conlon, UW Madison Department of Physics
- Host: Sridhara Dasu
- Physics Department Colloquium
- Holiday Colloquium
- Time: 3:30 pm - 4:30 pm
- Place: 2103 Chamberlin Hall
- Speaker: 2019 Physics Ph.D. Cohort, UW-Madison
- Host: 2019 Physics Ph.D. Cohort