Events During the Week of January 26th through February 2nd, 2020
Monday, January 27th, 2020
- Plasma Physics (Physics/ECE/NE 922) Seminar
- WHAM: The Wisconsin HTS Axisymmetric Mirror
- Time: 12:05 pm - 12:55 pm
- Place: 2241 Chamberlin Hall
- Speaker: Cary Forest, Prager Professor of Experimental Physics, Director of the Wisconsin Plasma Physics Laboratory
- Abstract: Recent physics breakthroughs, critical technological advances, and an attractive set of near term applications make the axisymmetric mirror ripe for new investment. A public-private partnership (UW Madison, MIT and Commonwealth Fusion Systems) has been formed to build and operate a compact, high-field simple mirror that will retire the physics risks of sustaining good confinement and MHD stability and the key technology risk of building the high field magnets needed to take the next big step along the mirror line. Success would qualify the design of a low cost BEAT (Break-Even Axisymmetric Tandem) experiment and offer a simpler and more economical approach to fusion energy than offered in conventional toroidal schemes.
- Host: Jan Egedal
Tuesday, January 28th, 2020
- Chaos & Complex Systems Seminar
- A conditional Gaussian framework for assimilating and predicting complex nonlinear turbulent dynamical systems
- Time: 12:05 pm - 1:00 pm
- Place: 4274 Chamberlin (refreshments will be served)
- Speaker: Nan Chen, UW Department of Mathematics
- Abstract: A conditional Gaussian nonlinear and non-Gaussian framework is developed and is applied to study data assimilation, uncertainty quantification and prediction of complex nonlinear turbulent dynamical systems. The talk will contain the following topics: recovering turbulent ocean flows, predicting non-Gaussian atmosphere phenomena including extreme events, solving the time evolution of high-dimensional probability density function, parameter estimation and recovering the hidden states in complex systems.
- Host: Clint Sprott
- "Physics Today" Undergrad Colloquium (Physics 301)
- Laboratory plasma physics and magnetic confinement fusion
- Time: 1:20 pm - 2:10 pm
- Place: 2241 Chamberlin Hall
- Speaker: Karsten McCollam, UW Madison Department of Physics
- Host: Sridhara Dasu
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Multi-messenger astrophysics with high-energy neutrinos in the coming decade
- Time: 3:30 pm
- Place: Room 4274, Chamberlin
- Speaker: Marcos Santander
- Abstract: Neutrinos are unique messengers from the high-energy universe. They can escape dense astrophysical environments, undeterred by intervening matter and radiation fields. The detection of high-energy astrophysical neutrinos in the TeV-PeV range by IceCube allows us to probe extreme cosmic sources and understand their emission processes in ways what would not be possible with photons alone. Enabling neutrino astrophysics in the coming decade will rest not only on the construction of new, more sensitive facilities, but also on the combined operation of multiple observatories capable of identifying additional tracers of hadronic emission. I will present a short overview of recent highlights from the neutrino sky and introduce a vision for how the coordinated operation of current and future multi-messenger observatories will help us deliver answers to some of the most pressing questions in high-energy astrophysics.
- Host: Albrecht Karle
- Council Meeting
- Time: 4:30 pm - 5:30 pm
- Place: 2314 Chamberlin Hall
- Host: Sridhara Dasu
Wednesday, January 29th, 2020
- Department Meeting
- Time: 12:15 pm - 1:15 pm
- Place: B343 Sterling Hall
- Speaker: Sridhara Dasu, Department Chair
- Host: Sridhara Dasu
- Atomic Physics Seminar
- Results and challenges from a Helium-Neon comagnetometer with SERF readout
- Time: 1:00 pm
- Place: 5310 Chamberlin Hall
- Speaker: William Terrano, Princeton
- Abstract: We have built a comagnetometer that compares Helium-3 and Neon-21 precession frequencies using a SERF magnetometer. Spin-exchange interactions are suppressed with a sequence of RF pulses. I will discuss the operation of the system, and our current sensitivity, which has reached 7 nHz in 2000 seconds and below 1 nHz in a day. I will discuss several important experimental techniques that allowed us to reach that level, as well as some outstanding challenges and unexplained phenomena.
- Host: Thrasher
- Theory Seminar (High Energy/Cosmology)
- Fundamental physics with CMB and galaxy surveys
- Time: 4:00 pm
- Place: 5280 Chamberlin
- Speaker: Moritz Münchmeyer, Perimeter
- Abstract: Upcoming experiments such as the Simons Observatory, DESI and LSST probe the universe with extremely high resolution. This upcoming data provides us with great opportunities for fundamental physics, such as probing the initial conditions of the universe. However, the vastness and extreme complexity of this interrelated data requires new methods to make sense of it. I will describe two ways forward, one based on theoretical understanding and one based on computation. In the former, I show how CMB and galaxy data can be combined in a new way to give unprecedentedly tight constraints on aspects of primordial physics. In the latter, I describe a step towards performing precision cosmology with machine learning, in a way that builds on the powerful physical and statistical methodology that has led to the success of observational cosmology.
- Host: Dan Chung
Thursday, January 30th, 2020
- R. G. Herb Condensed Matter Seminar
- Nanomechanical resonators for quantum optomechanics and precision metrology
- Time: 10:00 am
- Place: 5310 Chamberlin Hall
- Speaker: Robinjeet Singh , Joint Quantum Institute NIST (Gaithersburg) and the University of Maryland
- Abstract: Nanomechanical resonators serve as excellent candidates for high precision sensing and transduction, owing to their high mechanical quality factor. Applications include coherent frequency conversion for quantum networks, measurement below the Standard Quantum Limit, and precision metrology for quantities such as temperature and pressure. Our work focuses on designing, fabricating, and optically probing nanomechanical resonators made out of various insulator and semiconductor materials for applications including quantum metrology and force sensing, optical trapping of mechanical states, and efficient electro-optic transduction of information with potential application in superconducting quantum computing.
- Host: Saffman
- Cosmology Journal Club
- Time: 12:00 pm - 1:00 pm
- Place: 5242 Chamberlin Hall
- Abstract: http://cmb.physics.wisc.edu/journal/index.html
We discuss papers from arxiv.org related to cosmology each week. All are welcome and feel free to bring your lunch. If there is a paper you would like to present, or have questions or comments, please email Ross Cawthon (cawthon@wisc.edu) and Santanu Das (sdas33@wisc.edu). - Astronomy Colloquium
- Some Interesting issues in Galactic Dynamics
- Time: 3:30 pm - 5:00 pm
- Place: 4421 Sterling Hall, Coffee and cookies 3:30 PM, Talk begins 3:45 PM
- Speaker: Professor Elena D'onghia, UW Madison Astronomy Department
- Abstract: The Gaia satellite is currently mapping the phase-space of a few million stars in the solar neighborhood showing time-varying phenomena. About 350,000 stars within 200 pc of the Sun are identified in streams, bundles of stars that move together in the same direction with a velocity that is distinct from neighboring stars. I will present a set of N-body simulations of the Milky Way disk that shows the role of a long stellar bar and spiral arms in understanding the complex kinematics of the solar vicinity. Finally, the passage of Sagittarius dwarf galaxy induces rapid time-variations in the potential that lead to a significant bias of the Oort limit through the Jeans modeling. This calls for the development of non-equilibrium methods to estimate the dynamical matter density locally and in the outer disk.
Friday, January 31st, 2020
- Department Meeting
- CLOSED meeting to discuss faculty personnel matters
- Time: 12:15 pm - 1:05 pm
- Place: B343 Sterling
- Speaker: SRIDHARA DASU, UW PHYISCS
- CLOSED TO ALL BUT TENURED FACULTY.
- Physics Department Colloquium
- Magnetic reconnection: where are we and where are we going?
- Time: 3:30 pm
- Place: 2241 Chamberlin Hall
- Speaker: Michael Hesse, University of Bergen, Norway
- Abstract: Magnetic reconnection is the engine behind the often-explosive conversion of magnetic energy to the energy of particles. Due to this conversion as well as its plasma transport properties, it powers solar eruptions, magnetospheric substorms and storms and the aurora. Further away, in astrophysical systems, it is believed to be tied to gamma ray bursts, accretion disks, and other energy release processes, while it can cause violent disruptions in fusion machines. Due to the extremely small scale size of its central diffusion region, the basic mechanisms behind reconnection have been elusive for many decades. Courtesy of NASA’s Magnetospheric Multiscale mission this has changed in the last three years. This presentation will start with a summary of our present knowledge and present an outlook to open science questions and applications of the new knowledge.
- Host: Jan Egedal