Events at Physics |
Events During the Week of April 18th through April 25th, 2010
Monday, April 19th, 2010
- Plasma Physics (Physics/ECE/NE 922) Seminar
- Multi-Energy SXR Imaging for Magnetically Confined Fusion Studies
- Time: 12:05 pm
- Place: 2241 Chamberlin Hall
- Speaker: Luis Felpe Delgado-Aparicio, Princeton Plasma Physics Laboratory
Tuesday, April 20th, 2010
- Chaos & Complex Systems Seminar
- The Dynamics of Performance Management: Governance Reform Amidst Complexity
- Time: 12:05 pm
- Place: 4274 Chamberlin Hall
- Speaker: Donald Moynihan, UW-Madison La Folette School of Public Affairs
- Abstract: Professor Moynihan examines efforts to make the public sector more focused on outcomes through performance measurement techniques. Bureaucrats use the data for different purposes, and with different consequences, some unintended. This talk will summarize these reforms, their consequences, and the particular factors that affect how public actors use performance data.<br>
<br> - Astronomy Colloquium
- Modeling surface velocity fields from tidal interactions: the one-layer approximation
- Time: 3:30 pm - 5:00 pm
- Place: 3425 Sterling Hall
- Speaker: Gloria Konigsberger, UNAM
- Abstract: Binary stars in eccentric orbits are the clearest example of stars whose equatorial rotation velocity is not synchronized with orbital motion. Under these conditions, the surface velocity field is perturbed from its purely rotational nature, thus modifying the shape of the observationally-detectable photospheric absorption lines on a variety of timescales. Absorption lines are used to derive basic stellar parameters
and to gain a better physical understanding of stars. Although their variability is often interpreted in terms of non-radial pulsation theory, it is important to understand the nature of the surface velocity fields that are induced by the tidal interactions alone, especially under conditions of rapid rotation and large orbital eccentricity where the perturbations can become highly non-linear. We use a time-marching numerical calculation from first principles to compute the surface velocity field due to the tidal interaction (Moreno &amp;amp; Koenigsberger 1999; Toledano et al. 2007). This velocity field is then projected along the line-of-sight to the observer to predict the orbital phase-dependent line-profile variability (Moreno et al. 2005). In this talk, the general characteristics of our model will be described and we'll discuss its predictions for synchronization timescales in very eccentric binaries. In addition, we will show that the general characteristics of the theoretical photospheric line-profiles compare favorably with observational data of the short-period B-type binary system Spica (Harrington et al. 2009). It is interesting to note that because tidal flows are associated with viscous shear energy dissipation, the atmospheric structure of an asynchronously rotating binary star could differ significantly from that of a single star.
- Host: Prof John Gallagher
Wednesday, April 21st, 2010
- Department Meeting
- Time: 12:15 pm
- Place: 5310 Chamberlin Hall
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- A search for ultrahigh energy neutrinos in the ANITA experiment
- Time: 2:00 pm
- Place: 4274 Chamberlin Hall
- Speaker: Dr. Brian Mercurio, The Ohio State University
- Abstract: Cosmic rays with energy greater than about 1020 eV are expected to lose energy through interactions with the cosmic microwave background in what is known as the GZK process. Although the GZK process makes the universe opaque to the highest energy cosmic rays, it also results in the production of neutrinos that can travel nearly unattenuated from even the farthest galaxies. Because neutrinos have no electric charge, their direction of travel is not affected by intergalactic magnetic fields and they can point back to their sources. The Antarctic Impulsive Transient Antenna (ANITA) experiment is designed to detect GZK neutrinos with energy greater than 1018 eV. Antennas hanging from a balloon 35 km over Antarctica search for radio signals from neutrino-induced particle showers in the ice. ANITA did not discover neutrinos in this energy range, and it set a new upper limit on the neutrino flux above 1019 eV. The 2006-2007 flight also detected 16 signals that were consistent with radio emission from air showers above the ice.
- Host: Peter Timbie
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- Core Collapse Supernova Neutrino Detection
- Time: 4:00 pm
- Place: 4274 Chamberlin
- Speaker: Kate Scholberg, Duke University
- Abstract: When a massive star collapses at the end of its life, nearly all of the gravitational binding energy of the resulting remnant is released in the form of neutrinos. I will discuss the nature of the core collapse neutrino burst and what we can learn from its detection. I will cover supernova neutrino detection techniques, and prospects for future supernova-neutrino-sensitive experiments.
- Host: Albrecht Karle
Thursday, April 22nd, 2010
- R. G. Herb Condensed Matter Seminar
- Emergent Supersymmetry and String in Condensed Matter Systems
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Sung-Sik Lee, McMaster University
- Abstract: Quantum field theories arise as low energy effective descriptions in quantum many-body systems. Although strongly coupled quantum field theories are rather common, there is no systematic way of understanding those theories. In this talk, I will discuss about two condensed matter systems where non-perturbative tools may shed some light on strongly correlated systems. In the first part, I will talk about a 2+1 dimensional lattice model where supersymmetry emerges at a quantum critical point. In the second part, I will discuss about a 2+1 dimensional non-Fermi liquid state whose low energy effective theory is related to matrix/string theory.
- Host: Andrey Chubukov
Friday, April 23rd, 2010
- Physics & Astronomy Department
- Senior Sendoff Pizza Party
- Time: 12:00 pm
- Place: Courtyard between Chamberlin & Sterling (weather permitting)
- Abstract: Pizza and Soda.
- Host: Chung
- Special Plasma Theory Seminar
- Two Novel Diagnostic Techniques for Spherical Tokamaks (plus a bit of biology)
- Time: 12:00 pm
- Place: 414 ERB
- Speaker: Dr. Roddy Vann, University of York, York, UK
- Theory/Phenomenology Seminar
- Prospects for Hypercharged and Gaugino AMSB at the LHC
- Time: 2:30 pm - 3:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Howie Baer, University of Oklahoma
- Host: V. Barger
- Physics Department Colloquium
- The Transient Revolution in Astrophysics
- Time: 4:00 pm
- Place: 2241 Chamberlin Hall (coffee at 3:30 pm)
- Speaker: Eliot Quataert, UC-Berkeley
- Abstract: The advent of large astronomical surveys based on rapid advances in detector technology and data storage is generating an unprecedented amount of data on time-variable astronomical objects, up to 100 Terabytes per night in the coming decade. In addition to providing new insights into a wide variety of known phenomena (e.g., variable stars, supernovae, and black holes), historical analogues suggest that these surveys are likely to discover entirely new classes of astronomical objects. I will illustrate the discovery potential of the current generation of astrophysical transient surveys by focusing on two concrete examples of "known unknowns." The first is a "kilonova" produced by the decay of heavy elements created during the merger of two neutron stars or a neutron star and a black hole; a similar transient can be produced during the collapse of a white dwarf to a neutron star. These events are particularly interesting since they are the likely progenitors of some gamma-ray bursts and are also the primary target for km-scale gravitational wave observatories such as Advanced LIGO. The second "known unknown" I will highlight is a ~ week-long electromagnetic flare produced by the tidal disruption of a star that passes close to the event horizon of a massive black hole at the center of a galaxy. The study and characterization of kilonovae and tidal disruption events in the coming years will open up a new window onto the physics and astrophysics of compact objects in the universe.
- Host: Forest and Zweibel