Events at Physics |
Events During the Week of February 28th through March 7th, 2010
Monday, March 1st, 2010
- Plasma Theory Seminar
- Spontaneous Stochasticity and the Breakdown of Flux-Freezing in a Turbulent Plasma
- Time: 4:00 pm
- Place: 514 ERB
- Speaker: G. L. Eyink, John Hopkins University
Tuesday, March 2nd, 2010
- Chaos & Complex Systems Seminar
- Overview of Satellite-based Aviation Application for Detection of Thunderstorms, Turbulence and Volcanic Ash
- Time: 12:05 pm
- Place: 4274 Chamberlin Hall
- Speaker: Wayne Feltz, UW-Madison, Dept. of Space Science and Engineering Center
- Abstract: The University of Wisconsin-Madison Cooperative Institute for Meteorological Satellite Studies (CIMSS) Satellite Nowcasting and Aviation APplication (SNAAP) team is heavily involved in research to develop satellite-based nowcasting tools (0-3 hour forecast) for improving aviation weather forecasting. Current areas of research focus on satellite detection of aviation hazards such as convection, turbulence, and volcanic ash using current and future weather satellite systems. This seminar will overview this research as well as in context toward improvement of future air transportation route planning and warning for the general public.
- Astronomy Colloquium
- Interstellar Constraints on the Evolution of Cosmic Lithium
- Time: 3:30 pm - 5:00 pm
- Place: 3425 Sterling Hall
- Speaker: Chris Howk, Notre Dame University, Physics Dept
- Abstract: The cosmic abundance of lithium continues to represent a conundrum, as predictions from standard theories of Big Bang nucleosynthesis are inconsistent with measurements in the atmospheres of the lowest-metallicity stars. This discrepancy may be caused by astrophysical effects, such as the destruction of Li in the stars over their lifetimes, although no fully satisfactory astrophysical explanation has been proposed. Alternatively, it may also be explained by new physics in the early universe, e.g., by the early decay of particle dark matter. We are following an alternate approach to studying the cosmic Li abundance: the use of interstellar gas-phase Li in low-metallicity galaxies as a constraint on the primordial abundance and the cosmic evolution of Li. I will present measurement of gas-phase Li in the Small Magellanic Cloud, the first such measurement beyond the Milky Way. I will discuss the implications of our measurements and the prospects for future advances in this area.
- Host: Matt Haffner
Wednesday, March 3rd, 2010
- Department Meeting
- Time: 12:15 pm
- Place: 5310 Chamberlin Hall
- Seminar
- From Space Surveillance to Microelectronics: A Survey of Research at M.I.T. Lincoln Laboratory
- Time: 6:00 pm
- Place: 4274 Chamberlin Hall (refreshments will be served)
- Speaker: Dr. Matthew Vanderhill, MIT Lincoln Laboratory
- Abstract: Lincoln Laboratory, a federal research and development center* operated by the Massachusetts Institute of Technology, conducts a wide variety of applied and basic research in such mission areas as, advanced electronics and optical materials, space and terrestrial surveillance, communication systems, radar and optical systems technology, air traffic control, and air and missile defense technology. The presentation will describe the research conducted, what MIT Lincoln Laboratory offers as a workplace, and why you should consider Lincoln as your next employer . Whether your employment plans are nearly complete or just starting to be formed, you are invited to come to this informal presentation. Refreshments will be served.
- Host: R. Lefkow
Thursday, March 4th, 2010
- R. G. Herb Condensed Matter Seminar
- Fermi Surface investigation across the quantum critical point in CeIrIn5 and CeCoIn5 via de Haas van Alphen measurements
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: Cidgem Capan, UC-Irvine
- Abstract: A quantum critical point (QCP) is a continuous ground state transformation at T=0, tuned by an external parameter such as pressure, chemical doping or magnetic field. The critical behavior associated with this T=0 thermodynamic singularity may be the common feature underlying the similar phase diagrams found in a wide variety of strongly correlated systems, including cuprates, ruthenates, heavy fermions and iron pnictides. Among these systems, the heavy fermion compounds, rare-earth materials exhibiting large effective masses, have played a particularly important role for investigating the evolution of the Fermi surface across a QCP. In these materials it is the competing tendency of conduction electrons to screen or to mediate a magnetic coupling among the f-electrons that ultimately leads to a QCP. The important and still open question regarding the underlying mechanism of the QCP is whether the Fermi surface volume changes abruptly at the onset of magnetic ordering. Following a broad introduction, I will focus on two heavy fermion superconductors: CeMIn5 with M=Co,Ir. These recently discovered compounds illustrate well the shortcomings of our current understanding of quantum criticality: despite the thermodynamic and transport evidence for non-Fermi Liquid behavior in these systems, their Fermi surface, as investigated by de Haas van Alphen effect, does not show a drastic change across the putative QCP. The implications and possible scenarios will be discussed.
- Host: Natalia Perkins
Friday, March 5th, 2010
- Physics Department Colloquium
- Uncovering the Nature of Dark Matter with Direct Detection Experiments. Status and Prospects from a XENON Perspective.
- Time: 4:00 pm
- Place: 2241 Chamberlin Hall (coffee at 3:30 pm)
- Speaker: Uwe Oberlack, Rice University
- Abstract: More than 80% of the matter in the universe is in the form of non-baryonic Dark Matter. "Regular" matter makes up less than 5% of the matter and energy content of the universe. Understanding the nature of Dark Matter ranks therefore among the outstanding questions in physics today. The rapid formation of structure in the early universe from small density variations as observed in the Cosmic Microwave Background supports the idea of Dark Matter being a thermal relic of Weakly Interacting Massive Particles (WIMPs). WIMPs can be detected in principle by their interactions with regular matter. The XENON Dark Matter program pursues the goal of directly detecting nuclear recoils resulting from scattering with Weakly Interacting Massive Particles (WIMPs), using increasingly more sensitive experiments. The detector concept consists of a dual-phase liquid/gas xenon time projection chamber with a low energy threshold. It discriminates against background using simultaneous measurements of the primary scintillation light and the charge signal, resulting from interactions in the noble liquid. Following the successful XENON10, the current experiment XENON100 features 10 times greater sensitive mass and 100 times lower background. XENON100 aims at improving sensitivity by a factor of 20 over current limits. I will provide an overview of the field, describe the status of XENON100, and discuss its physics reach along with future prospects of detectors at the ton scale.
- Host: Westerhoff