Events at Physics |
Events During the Week of October 31st through November 7th, 2010
Monday, November 1st, 2010
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Peak Neoclassical Toroidal Viscosity in DII-D
- Time: 12:05 pm
- Place: 2535 Engineering Hall
- Speaker: Andrew Cole, UW-Madison Dept of Engineering Physics
- Plasma Theory Seminar
- Nonlinear Evolution of Edge Localized MHD Instabilities: A Comparison of Ballooning and Peeling-Dominated Equilibria
- Time: 4:00 pm
- Place: 514 ERB
- Speaker: Bonnie Burke, UW-Madison Dept. of Physcs
Tuesday, November 2nd, 2010
- Chaos & Complex Systems Seminar
- Water: Wild Card in the Climate System
- Time: 12:05 pm
- Place: 4274 Chamberlin Hall
- Speaker: John Young, UW-Madison Department of Atmospheric and Oceanic Sciences
- String Theory Seminar
- Phenomenology of D-branes at Toric Singularities
- Time: 4:00 pm
- Place: 5280 Chamberlin
- Speaker: Sven Krippendorf, Cambridge University
Wednesday, November 3rd, 2010
- Department Meeting
- Time: 12:15 pm
- Place: 5310 Chamberlin Hall
Thursday, November 4th, 2010
- Astronomy Colloquium
- Resonant Stripping as the origin of dwarf spheroidal galaxies
- Time: 3:30 pm
- Place: 4421 Sterling Hall Same Location
- Speaker: Elena D'Onghia, Harvard CfA
- Abstract: The most dark matter dominated galaxies known are the dwarf spheroidals,but their origin is still uncertain. The recent discovery of ultra-faint dwarf spheroidals around the Milky Way further challenges our understanding of how low-luminosity galaxies originate and evolve because of their even more extreme paucity of gas and stars relative to their dark matter content. By employing numerical simulations I will show that interactions between dwarf disc galaxies can excite a gravitational resonance that immediately drives their evolution into spheroidals. This effect, which is purely gravitational in nature, applies to gas and stars and is distinct from other mechanisms which have been<br>
proposed up to now to explain the origin of dwarf spheroidals, such as merging, galaxy-galaxy harassment and more general heating processes, or tidal and ram pressure stripping. Using a new analytic formalism we developed based on the linear perturbation theory I will show the nature and the efficiency of the resonant process and its applicability to the formation of tails of stars and streams of gas. - Host: Prof John Gallagher
- Graduate Introductory Seminar
- Phenomenology
- Time: 5:30 pm - 6:30 pm
- Place: 2223 Chamberlin Hall
- Speaker: Barger, Everett, Han
Friday, November 5th, 2010
- Special Atomic Physics Seminar
- Simultaneous Trapping of Ultracold Gases of Lithium and Ytterbium
- Time: 2:30 pm
- Place: 5310 Chamberlin
- Speaker: Vlad Ivanov, University of Washington
- Abstract: Simultaneous trapping of multiple ultra-cold atomic species presents a starting point for a wide range of experiments such probing strongly interacting quantum gases, exploring aspects of superfluidity, and study induced interspecies scattering resonances. It is also an important step toward synthesis of stable, polar molecules, which may be used to study new dipolar quantum superfluids, as building blocks in scalable quantum computing schemes, and as sensitive probes of fundamental physics. We choose lithium (Li) and ytterbium (Yb) atoms as the two constituent species of our experiment for several reasons. Both Li and Yb possess stable bosonic and fermionic isotopes which have been brought to quantum degeneracy in single species experiments. Li is a one-electron atom and Yb is a two-electron atom, allowing for species selective trapping techniques using external magnetic fields, as well as magnetic trapping of synthesized, diatomic LiYb molecules. A large electric dipole moment in the molecular ground state allows for studies of strongly dipolar quantum gases, and makes LiYb a promising candidate for a sensitive electron EDM measurement. We achieve simultaneous magneto-optical traps (MOTs) of lithium and ytterbium. Because the two MOTs are optimized at different magnetic field settings, the species are loaded in optical dipole trap sequentially; Yb is allowed to fully load, and is then transferred to a far off-resonant optical dipole trap, (ODT) before Li is introduced into the system. After transferring the Li to the ODT we routinely obtain ~1 million optically trapped atoms of each species, at temperatures of about 100 μK. We use obtained Li-Yb mixture in ODT for study of its collisional stability, furthermore we observe thermalization of the mixture that allows us to extract collisional cross-section of ultra-cold Li and Yb atoms.
- Host: Mark Saffman
- Phenomenology Seminar
- Theory/Phenomenology Seminar
- Model Building in the LHC Era
- Time: 2:30 pm - 3:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Neil Christensen, University of Michigan
- Physics Department Colloquium
- Reionization and Cosmology with 21 cm Fluctuations
- Time: 4:00 pm
- Place: 2241 Chamberlin Hall (coffee at 3:30 pm)
- Speaker: Miguel Morales, University of Washington
- Abstract: Measurement of the spatial distribution of neutral hydrogen via
the redshifted 21 cm line promises to revolutionize our knowledge of the Epoch of Reionization (EoR), and may provide a powerful new tool for observational cosmology at redshifts 1-4. I will discuss how we plan to observe the faint 21 cm fluctuations in the face of strong foregrounds, the status of the first generation EoR machines, and the application of 21-cm tomography to cosmography and dark energy measurements after reionization. - Host: Timbie