Events at Physics |
Events on Thursday, November 11th, 2010
- R. G. Herb Condensed Matter Seminar
- Experiments with atoms in optical lattices
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: David Weiss, Penn State University
- Abstract: Atoms trapped in optical lattices are versatile systems that can be used to model many-body systems, as quantum computing resources, and for precision measurements. I will explain in general how such experiments work, and describe in particular our experiments at Penn State. The focus of the talk will be predominantly on 1D Bose gases, which can provide unique insights into the foundations of quantum statistical mechanics. Other experiments will also be mentioned, like trapping arrays of single atoms on the road to making a quantum computer.
- Host: Robert McDermott
- Astronomy Colloquium
- Photoionization of High Altitude Gas in a Supernova-Driven Turbulent Interstellar Medium
- Time: 3:30 pm - 5:00 pm
- Place: 4421 Sterling Hall
- Speaker: Kenny Wood, University of St Andrews, School of Physics and Astronomy
- Abstract: One of the major questions in studies of widespread diffuse ionized gas in galaxies is how ionizing photons can penetrate from OB stars in midplane regions to ionize gas at large heights above the plane. A three dimensional ISM provides the solution - low density voids allow photons to travel much farther than in a smoothly distributed ISM. I will show new results of photoionization calculations in a 3D Supernovae driven hydro simulation of the ISM. Ionizing photons can easily reach to large distances from the midplane. However, the resulting emission measure distributions are broader than observed in the Milky Way and other galaxies. A possible reason for this is the absence of magnetic fields in the dynamical simulations. Our simulations also place limits on the survivability of neutral clouds in the Galactic halo exposed to the ionizing radiation percolating through the models. I will also summarize recent Spitzer observations of gas many kiloparsecs from the midplane of the edge-on galaxy NGC891 that indicate an additional population of very hot ionizing sources are required to explain the observed emission line ratios.
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Discovery of gamma-ray Emission from Andromeda Galaxy
- Time: 4:00 pm
- Place: 4274 Chamberlin
- Speaker: Hakki Ogelman, University of Wisconsin at Madison
- Abstract: 2 years worth of archival FERMI-LAT data was used to search forgamma-ray
emission from the Andromeda galaxy; the data show no noticeabla gamma-ray image.On-off source aperture photometry using a CO image template shows a 7 sigma excess in the on-source apertures in comparison to the off-source apertures. yielding a flux of (4.95 +/- 0.71`)x10^(-8) photonscm^-2 s^-1 at energies E>100 MeV. The likely origin of this flux will be discussed in terms of the cosmic-ray content and the interstellar gas at Andromeda. - Host: Daniel Chung
- Graduate Introductory Seminar
- String Theory & Theoretical Cosmology
- Time: 5:30 pm - 6:30 pm
- Place: 2223 Chamberlin Hall
- Speaker: Chung, Hashimoto, Shiu