Events at Physics
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Events During the Week of January 29th through February 5th, 2017
- Plasma Physics (Physics/ECE/NE 922) Seminar
- New Insights into the Origin of Cosmic Rays
- Time: 12:00 pm
- Place: 2317 Engineering Hall
- Speaker: Dr. Damiano Caprioli, University of Chicago, USA
- Cosmology Journal Club
- An Informal discussion about a broad variety of arXiv papers related to Cosmology
- Time: 12:15 pm
- Place: 5242 Chamberlin Hall
- Abstract: Please visit the following link for more details:
Please 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 Amol Upadhye (email@example.com).
- Host: Amol Upadhye
- Atomic Physics Seminar
- Building materials from light: Photonic Landau levels and Rydberg-mediated interactions
- Time: 12:00 pm
- Place: 5280 Chamberlin Hall
- Speaker: Ariel Sommer, MIT
- Abstract: Advances in the control of light propagation and photon-photon interactions have lead to a new notion of photonic materials -- states of light that resemble material systems. I will describe our experimental approach to photonic materials, in which we use a degenerate non-planar optical resonator to realize a two-dimensional photon gas with an effective magnetic field. We observe photonic Landau levels, indicating a strong effective magnetic field, and a singularity of spatial curvature arising from the effectively conical geometry of our photon gas. Spatial curvature provides a novel probe of quantum Hall states, allowing us to make the first experimental measurement of the mean orbital spin, which characterizes topological phases. To realize photon-photon interactions, we demonstrate hybridization of photons in an optical resonator with atomic Rydberg excitations. Future work will investigate ordered states of interacting photons, including crystalline and fractional quantum Hall states.
- Host: Thad Walker
- Chaos & Complex Systems Seminar
- Climate change science, impacts, and mitigation strategies
- Time: 12:05 pm
- Place: 4274 Chamberlin (refreshments will be served)
- Speaker: Susan Nossal, UW Department of Physics
- Abstract: Deep reductions in greenhouse gas emissions are required to avert catastrophic impacts of climate change. This presentation will briefly overview some of the complexities associated with climate change science and impacts. One example is the influence on the upper atmosphere of increases in greenhouse gases and of the solar cycle, a major source of natural variability in this region. The talk will also include discussion of climate change mitigation strategies.
- Host: Clint Sprott
- Theory Seminar (High Energy/Cosmology)
- Top Yukawa coupling enhancement in the composite Higgs models
- Time: 3:30 pm
- Place: 5280 Chamberlin
- Speaker: Da Liu, Argonne National Laboratory
- Abstract: The LHC Run 1 data prefer larger top Yukawa coupling and smaller ggh coupling. In this talk I will discuss about the possibility of explaining this behaviour in the composite Higgs models. We have found that<br>
the difference of the top Yukawa coupling strength ct and the ggh coupling strength cg is strongly related with Higgs mass term, i.e. a positive value of ct - cg will usually lead to positive <br>
Higgs mass term. In other words, we need other contributions to the Higgs potential to trigger the EWSB in order to fit the data. We also propose one possible solution to this problem.
- Host: Josh Berger
- No events scheduled
- Astronomy Colloquium
- "Gas and Star Formation In Minor Mergers: Molecular gas feeding the central starbursts in NGC 1614 and the Medusa mergers"
- Time: 3:30 pm
- Place: 4421 Sterling Hall, Coffee and Cookies 3:30 pm, Talk begins at 3:45 PM
- Speaker: Sabine Koenig, Chalmers University
- Abstract: Galaxy evolution is a fundamental part of the overall evolution of the Universe - from the largest spatial scales (ruled by dark matter), to the smallest dominated by dissipative baryons that can form stars and grow supermassive black holes (SMBHs). Interactions and mergers are a known and efficient mechanism for galaxy growth. The focus on merger studies often lies on major mergers (equal mass progenitors) and their evolution although minor mergers (unequal mass progenitors) occur much more frequently. The impact of minor mergers on the growth of SMBHs and star formation is profound - about half of the star formation activity in the local Universe is the result of minor mergers. Studying molecular gas properties in these systems, especially how molecular gas is feeding starburst and AGN activities, therefore gives us important clues to the onset and evolution of interaction-triggered starbursts. Understanding how gas is feeding starburst and AGN activities in these objects, in particular, is paramount to understand the overall evolution of the Universe. In this talk I will present an overview of the molecular gas properties of two exceptional minor mergers: NGC 1614 and the Medusa merger.
- Host: Professor Jay Gallagher
- Physics Department Colloquium
- Lab Astro and the Origins of the Chemical Elements
- Time: 3:30 pm
- Place: 2241 Chamberlin Hall
- Speaker: James E. Lawler, introduced by UW Emeritus Prof. Wilmer Anderson, UW-Madison
- Abstract: James E. Lawler, UW-Physics, 2017 Winner of the American Astronomical Society Laboratory Astrophysics Prize
Only a few of the lightest or primordial nuclei were made just after the Big Bang. Other light nuclei up to the Fe-group are made by fusion in stars. Heavier nuclei are made primarily via r(apid)-process and s(low)-process n(eutron)-capture events. Although the s-process n-capture is fairly well understood, the r-process n-capture events remain poorly understood. The relative role of Core Collapse SNe and n-star mergers will likely be understood in the next few decades. I will discuss recent studies of old Metal-Poor stars that are revealing some new details of nucleosynthesis. This progress is due to the availability of high resolution spectra from large ground based telescopes, access to the UV via HST, and better laboratory data