Events at Physics
Events on Thursday, September 19th, 2019
- R. G. Herb Condensed Matter Seminar
- Optical control of free-electron decoherence
- Time: 11:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Wayne Huang, Northwestern University
- Abstract: In electron grating diffraction, the peak width in the diffraction pattern is a direct measure of the free electron transverse coherence length. A broadened peak indicates decoherence of the free electron wavepacket. Using the above band-gap photoexcitation, we created a charge pattern on a GaAs surface that interacts with the diffracted electron matter wave through a dipole field. We observed a significant broadening of the diffraction peak as electrons flew over certain regions of the charge structure. The decoherence strength can be controlled through the excitation laser that is applied to the GaAs plate. As only one electron is present in the chamber at any time, such a system is suitable for studying decoherence of single electrons. In this talk, I will present some recent experimental results and discuss a possible decoherence model.
- Host: Saffman
- Cosmology Journal Club
- Time: 12:00 pm
- Place: 5242 Chamberlin Hall
- Abstract: Please visit the following link for more details:
Feel free to bring your lunch!
If you have questions or comments about this journal club, would like to propose a topic or volunteer to introduce a paper, please email Ross Cawthon (firstname.lastname@example.org) and Santanu Das (email@example.com).
- PGSC Professional Development Seminar
- Building a Free Professional Website for Your Research in 10 Minutes!
- Time: 2:30 pm
- Place: 5310 Chamberlin Hall
- Speaker: Rob Morgan, Physics PhD Graduate Student
- Abstract: The first Physics Graduate Student Council Professional Development Seminar! We will briefly outline the topics for the semester as an introduction to the seminar series. This session will focus on the importance of making yourself and your work accessible to collaborators and potential employers. Personal websites are the perfect tools for this purpose. There will be a step-by-step walkthrough to create a free, easy-to-use personal website. By the end, everyone will be online! Visit https://rmorgan10.github.io/UWMadisonPGSC-PD/ for more information.
- Host: Rob Morgan, graduate student
- Astronomy Colloquium
- The Geometry, Energetics, and Environment of the Binary Neutron Star Merger GW170817: The Radio View
- Time: 3:30 pm
- Place: 4421 Sterling Hall, Coffee and cookies 3:30 PM, Talk begins 3:45 PM
- Speaker: David Kaplan, UW Milwaukee Physics Department
- Abstract: I will discuss the major uncertainties regarding the geometry, energetics, and environment of the first EM/GW binary neutron star merger GW170817. In particular I will look at the origin of the radio emission, how it differs from the early-time optical/infrared emission, and what that tells us about how the explosion proceeded. I will show how constraints from the radio lightcurve, polarization, and Very Long Baseline Interferometry helped provide evidence for a broad, mildly relativistic "cocoon" along with a narrow jet. This broke degeneracies in the gravitational wave data analysis to provide inclination constraints and improved measurements of the Hubble Constant. Finally, I will talk about new events from LIGO's latest observing run.
- Host: UW Astronomy Department