Events at Physics |
Events During the Week of January 22nd through January 29th, 2023
Monday, January 23rd, 2023
- Academic Calendar
- Deadline for students to cancel spring enrollment and have no spring term record on transcript
- Abstract: *Note: actual end time may vary.* CONTACT: 262-3811, registrar@em.wisc.edu URL:
- Academic Calendar
- Graduate School Spring 2023: Spring degree window period deadline for master's students
- Time: 4:00 pm - 5:00 pm
- Abstract: CONTACT: 262-2433, gsacserv@grad.wisc.edu
- Academic Calendar
- Graduate School Spring 2023: Dissertator eligibility for spring 2023
- Time: 4:00 pm - 5:00 pm
- Abstract: CONTACT: 262-2433, gsacserv@grad.wisc.edu
- Academic Calendar
- Graduate School Spring 2023: Spring degree window period deadline for doctoral students
- Time: 11:55 pm - 12:55 am
- Abstract: Degree candidates must complete all steps: CONTACT: 262-2433, gsacserv@grad.wisc.edu
Tuesday, January 24th, 2023
- Academic Calendar
- Spring semester instruction begins
- Abstract: *Note: actual end time may vary.* URL:
Wednesday, January 25th, 2023
- Atomic Physics Seminar
- Precision measurements to search for gravitational waves and dark matter
- Time: 11:00 am - 12:00 pm
- Place: 5310 Chamberlin Hall
- Speaker: Nancy Aggarwal
- Abstract: Precision measurements are the key to unlocking various fundamental physics mysteries. In my talk, I will focus on two specific precision measurement experiments - a novel, optomechanical (OM) squeezer for third-generation gravitational wave (GW) detectors, and an experiment searching for the QCD axion mediating new forces in the laboratory. I will also give a sneak-peak into the future research plans for my group.
LIGO and VIRGO detectors deploy squeezed states of electromagnetic vacuum to reduce the quantum noise and enable detection of fainter GWs coming from sources further out in the universe. OM squeezers are based on radiation pressure interaction and hence can be used at any wavelength of light - a big advantage over currently used crystal squeezers that require a special nonlinearity at the desired wavelength. However, OM squeezing comes with its own problems, e.g. Brownian thermal motion washing away the quantum squeezing. For this reason, all previous OM squeezing effors have been at high frequencies and cryogenic temperatures. I will describe what it takes to generate and observe this quantum effect at room temperature and present the first room-temperature optomechanical squeezing results.
The axion is a novel particle proposed to solve the strong-CP problem in QCD, and is also one of the top candidates for dark matter. ARIADNE, under construction right now, will search for spin-dependent forces mediated by the QCD axion in the mass range 10^-6 - 10^-2 eV.
This is a precision measurement experiment that requires isolating a force equivalent to a magnetic field of 10^-20 T between golf-ball sized, moving objects, placed 50 um away from each other. I will describe the experiment concept, engineering challenges associated with it, and current experimental progress, including a new method to isolate magnetic dipoles as small as 10^-9 Am^2.
- Host: Thad Walker
- Department Meeting
- Time: 12:15 pm - 1:15 pm
- Place: B343 Sterling Hall
- Speaker: Mark Eriksson, UW-Madison
- Host: Mark Eriksson
Thursday, January 26th, 2023
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Reactor Neutrino Experiments in China: Daya Bay and JUNO
- Time: 2:30 pm - 3:30 pm
- Place: CH4274 /
- Speaker: Wei Wang, Sun Yat-sen University
- Abstract: Reactor neutrino experiments have played irreplaceable roles in the history of neutrino physics and in recent years, two major ones have been built in Southern China, a short-baseline one, the Daya Bay Reactor Neutrino Experiment, and a medium-baseline one, Jiangmen Underground Neutrino Observatory (JUNO), which is currently under construction. Daya Bay discovered the value of θ 13 successfully and currently also holds the best atmospheric mass-squared difference measurement. The unexpected large value of θ 13 has also made the neutrino mass ordering measurement possible using reactor neutrinos, which is what JUNO is aiming to resolve by carefully arranging two oscillation frequencies onto the same energy spectrum. In this talk, we will give a general review on neutrino oscillation, the Daya Bay latest results, the design of JUNO and its current status.
- Host: Albrecht Karle
- Astronomy Colloquium
- Seeking the nature of dark matter with the Milky Way halo and wide-field photometric surveys
- Time: 3:30 pm - 4:30 pm
- Place: 4421 Sterling Hall
- Speaker: Peter Ferguson, UW-Madison
- Abstract: The outer Milky Way halo is extremely dark matter dominated, and its stellar content is made up of accreted substructures that did not form in our Galaxy. Finding and characterizing these substructures, particularly ultra-faint dwarf galaxies and stellar streams, provides a unique probe of the nature and distribution of dark matter in the Milky Way. These efforts have been enabled by wide field photometric surveys such as the Sloan Digital Sky Survey (SDSS) and the Dark Energy Survey (DES). To continue to make progress in these efforts with current and upcoming surveys it is important to calibrate the data products precisely and understand the various survey selection functions. In this talk, I will discuss how we can learn about the nature of dark matter by studying the Milky Way halo substructures. Then I will share some of our efforts to find and characterize these substructures, focusing on stellar streams, with current surveys like the DECam Local Volume Exploration Survey (DELVE). Finally, I will discuss the current status of the Vera C. Rubin observatory and our efforts to ensure future discoveries with the Legacy Survey of Space and Time (LSST) through careful verification and validation of the survey data.
- Host: Ke Zhang
Friday, January 27th, 2023
- Academic Calendar
- Deadline for students (except Special and Guest) to begin initial Spring term enrollment without $50 late fee
- Abstract: *Note: actual end time may vary.* CONTACT: 262-3811, registrar@em.wisc.edu URL:
- Physics Department Colloquium
- The Importance of Being Eccentric
- Time: 3:30 pm - 4:30 pm
- Place: 2241 Chamberlin Hall
- Speaker: Ann-Marie Madigan, UC Boulder
- Abstract: The Importance of Being Eccentric The collective gravity of bodies on eccentric orbits is key to understanding the evolution of gravitational systems from planets to galaxies. In this talk, I will demonstrate wide-ranging implications of these dynamics such as the orbital clustering of icy bodies in the outer solar system (observations of which have motivated the Planet 9 hypothesis), the feeding of stars and gas to supermassive black holes, and surprising locations of galactic dark matter over-densities. Dr. Ann-Marie Madigan is an associate professor of Astrophysics and Planetary Sciences at the University of Colorado Boulder. Born in Dublin, she was one of the first students in Ireland to receive an undergraduate degree in Astronomy (at the University of Ireland, Galway). She received her PhD in astronomy from Leiden University in The Netherlands and was a NASA Einstein Postdoctoral Fellow at the University of California, Berkeley.
- Host: Shimon Kolkowitz