Events at Physics |
Events During the Week of February 18th through February 25th, 2018
Monday, February 19th, 2018
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Tokamak Disruption Simulation: Progress toward Comprehensive Modeling
- Time: 12:05 pm
- Place: 2241 Chamberlin Hall
- Speaker: Prof. Carl Sovinec, UW-Madison, Engineering Physics
- Abstract: Full-scale operation of the ITER experiment will produce plasma thermal energy and releasable magnetic energy on the order of hundreds of mega-Joules. Unplanned disruptions to these discharges will be capable of causing significant material damage to plasma-facing components and structures. Efforts to understand disruptive dynamics, and to engineering mitigation systems, include the development of comprehensive numerical models that can make predictions without destructive testing. In this presentation, previous efforts for simulating different forms of disruption are reviewed, and a relatively recent effort, based on the NIMROD code (https://nimrodteam.org) is presented. We find that the modeling of heat flux at the domain boundary has more significance than the modeling of particle flux for the evolution of global parameters and for the longevity of the simulated discharge. Fully three-dimensional simulations show that surface contact enhances instabilities which develop near the plasma surface, and these asymmetries lead to net horizontal forcing on the chamber wall. These results also highlight the importance of physical effects at the boundary of the modeled region. Plans for including more realistic boundary effects are discussed.
Tuesday, February 20th, 2018
- Department Meeting
- Closed Meeting to discuss faculty personnel matters
- Time: 12:00 pm - 12:30 pm
- Place: 5310 Chamberlin Hall
- Closed meeting to discuss personnel matters pursuant to Section 19.85(1)(c) of the Wisconsin Open Meetings Law. Closed to all but tenured faculty<br>
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- Host: Dasu
- Chaos & Complex Systems Seminar
- Interactions between environment and host epigenome: metabolism, the microbiota, and hibernation
- Time: 12:05 pm - 1:00 pm
- Place: 4274 Chamberlin (Refreshments will be served)
- Speaker: Kim Krautkramer, Wisconsin Institutes for Discovery
- Abstract: How do environmental stimuli/insults signal to the mammalian epigenome and what role do the microbiota play in this process? This talk will highlight recent and ongoing collaborative work aimed at understanding how environmental factors impact the host epigenome in mammals, including diet, maternal environment, and seasonal changes in body composition and metabolism in hibernators. We explore these questions using a variety of methods, including mass spectrometry, high throughput sequencing, and both wild-caught and gnotobiotic animal models.
- Host: Clint Sprott
- Council Meeting
- "Special" council meeting
- Time: 12:30 pm
- Place: 5310 Chamberlin Hall
- Host: Sridhara Dasu
- "Physics Today" Undergrad Colloquium (Physics 301)
- Quantum Bits in Silicon Quantum Dots
- Time: 1:20 pm - 2:10 pm
- Place: 2241 Chamberlin Hall
- Speaker: Mark A Eriksson, UW Madison Department of Physics
- Host: Wesley Smith
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- The neutrino quantum system and DUNE
- Time: 3:30 pm
- Place: 4274 Chamberlin Hall
- Speaker: Jonathan Miller, Fermilab
- Abstract: With the completion of Deep Underground Neutrino Experiment (DUNE) in the next decade, the continuation of this exciting era in neutrino physics is assured. Deep underground, based on Liquid Argon Time Projection Chamber (LArTPC) technology, with a total fiducial mass of 40-kton and utilizing the high-intensity neutrino beam produced at the Long Baseline Neutrino Facility (LBNF) at Fermilab, the DUNE program is rich and diverse. The center of this program is the measurement of the charge-parity violating phase (δCP), a free parameter in the PMNS matrix, which describes the relationship between neutrino propagating eigenstates and interaction eigenstates. This parameter can be measured by a sensitive measurement of neutrino interference and may be the primary source of the matter-antimatter asymmetry in the universe. DUNE is also sensitive to the neutrino ensemble from core-collapse supernovae, providing a unique tool to study astrophysical phenomena. In both situations, the neutrino source (supernova or LBNF), propagation and detection (LArTPC in DUNE) define a quantum system. Understanding and simulating this phenomenologically rich quantum system is important to the success of the DUNE program and opens up additional avenues of investigation.
- Host: Sridhara Dasu
Wednesday, February 21st, 2018
- Department Meeting
- Time: 12:15 pm
- Place: 5310 Chamberlin Hall
Thursday, February 22nd, 2018
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Where is all the antimatter?
- Time: 3:30 pm
- Place: 4274 Chamberlin Hall
- Speaker: Nuno Barros, University of Pennsylvania
- Abstract: Everything we know about the microscopic world tells us that the universe should be composed of equal parts matter and antimatter. All known particle interactions and decays always produce equal amount of each.
Yet all the known, observable, universe is composed solely of matter, suggesting that a small surplus of matter might have taken form shortly after the Big Bang.
A possible explanation for this asymmetry may be that neutrinos, unlike all other fundamental particles of Nature, may have behavior that distinguishes matter and antimatter. Ironically, the property that allows this is that neutrinos
and antineutrinos may be the same thing. Many experiments worldwide that are running or under construction, are investigating this possibility.
This talk will discuss this problem and the different approaches to address it in both present and upcoming neutrino
experiments, with particular emphasis on long baseline neutrino oscillations with DUNE and neutrinoless double beta decay with SNO+. The physics goals and expectations of these experiments will also be discussed. - Host: Sridhara Dasu
- Astronomy Colloquium
- The Positive Side of the Galactic Baryon Ledger: the Evidence for Cold Inflow
- Time: 3:30 pm - 5:00 pm
- Place: 4421 Sterling Hall, Cookies and coffee 3:30 pm , Talk starts at 3:45 pm
- Speaker: Chris Howk, University of Notre Dame
- Abstract: The flow of gas through galactic halos is crucial to the evolution of galaxies, as the nature of such flows can dictate the star formation properties of galaxies and regulate their metallicity. Outflows through the circumgalactic medium (CGM) carry metals away from galaxies (although many may return), while infalling metal-poor gas from the intergalactic medium dilutes the metals in galaxies and provides new fuel for star formation. The nature of the infalling baryons, in particular, is of great interest, but such gas has historically been difficult to identify. I'll review our work on galaxies both near and far that suggests the inflow of new matter is robust even in today's massive galaxies.
Friday, February 23rd, 2018
- Physics Department Colloquium
- A Brief History of Time(keeping): Metrology, quantum simulation, and tests of relativity with optical lattice clocks
- Time: 3:30 pm
- Place: 2241 Chamberlin Hall
- Speaker: Shimon Kolkowitz, UW-Madison
- Abstract: Optical lattice clocks (OLCs) are now the most stable and accurate timekeepers in the world, with fractional accuracies equivalent to neither losing nor gaining a second over the entire age of the universe. This unprecedented level of metrological precision offers sensitivity to new quantum, many-body, and fundamental physics effects, opening the door to exciting and unusual applications. This talk will provide an introduction to how and why time is measured, with an emphasis on OLCs and their applications. I will discuss recent progress on pushing OLCs to even greater levels of precision, as well as prospects for future improvement. I also will present results from a recent experiment in which we harnessed the precision of an OLC to simulate complex condensed matter phenomena. Finally, I will give a brief overview of emerging applications of OLCs, including research taking place here at UW-Madison into using clocks for gravitational wave detection, tests of general relativity, and searches for physics beyond the Standard Model.
- Host: Alex Levchenko