Events at Physics |
Events on Tuesday, January 31st, 2017
- 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 - 1:00 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