Events on Friday, February 3rd, 2023
- Academic Calendar
- Deadline for students to add, swap, or change sections in a Spring term course
- Abstract: *Note: actual end time may vary.* CONTACT: 262-3811, registrar@em.wisc.edu URL:
- Academic Calendar
- Deadline for students to begin initial Spring enrollment
- Abstract: *Note: actual end time may vary.* CONTACT: 262-3811, registrar@em.wisc.edu URL:
- Academic Calendar
- Deadline for students to drop a Spring term course and receive 100% tuition adjustment
- Abstract: *Note: actual end time may vary.* CONTACT: 262-3811, registrar@em.wisc.edu URL:
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Exploiting stellar explosion induced by the QCD phase transition in large-scale neutrino detectors
- Time: 2:00 pm - 3:00 pm
- Place: CH4274/https://uwmadison.zoom.us/j/94714568988?pwd=TnRuZFNQaFErZDZ6V29DL0VpSC9rUT09
- Speaker: Anna Suliga, UC Berkeley/UW Madison
- Abstract: Core-collapse supernovae are one of the most complex phenomena in the universe. Not only are they one of the sites of the production of the heavy elements which enable the existence of life, but their cores are also one of the densest environments we can indirectly probe. At such densities, the matter may no longer consist only of hadronic degrees of freedom but undergo a phase transition to quark matter. In this talk, I will discuss the implications of such a transition on the neutrino emission from core-collapse supernovae and how the detection of such a signal on Earth can be used to point to the location of the supernova and set stringent limits on the absolute active neutrino mass.
- Host: A. Baha Balantekin
- Physics Department Colloquium
- Multi-messenger scanning probe microscopy for the investigation of electronic properties of materials.
- Time: 3:30 pm - 4:30 pm
- Place: 2241 Chamberlin Hall
- Speaker: Victor Brar, UW Madison
- Abstract: Scanning probe microscopy is an imaging technique whereby a sharp tip is moved across a surface while locally measuring some material property with a resolution that can be sub-Angstrom. A wide range of material properties can be studied in this way, including surface conductance (scanning tunneling microscopy), physical structure (atomic force microscopy), and surface potential (Kelvin probe force microscopy). By combining these measurement techniques, a complete understanding of a material's properties can be developed that relates electron motion to underlying atomic structure. In this talk I will show how multiple scanning probe measurements can be performed on graphene to reveal how electrons scatter off and move around in-plane potential barriers formed by charged defects. By comparing measurements of the spatially varying surface potential with measurements of the electron wavefunction, the electron dynamics can be modeled precisely, and described using a single-particle wavefunction. As the electron temperature is increased, however, these measurements reveal a new hydrodynamic phase of the electron fluid emerges with a viscosity comparable to diesel fuel. Our scanned probe measurements show that this new phase exhibits a conductivity that is greater than ballistic conductance, and that the motion of electrons around barriers resembles that of water moving around pebbles in a stream.