Events at Physics |
Events on Thursday, October 30th, 2014
- R. G. Herb Condensed Matter Seminar
- Quantum Oscillations in Kondo Insulator SmB6
- Time: 10:00 am - 11:00 am
- Place: Chamberlin 5310
- Speaker: Lu Li, University of Michigan
- Abstract: In Kondo insulator samarium hexaboride SmB6, strong correlation and<br>
band hybridization lead to a diverging resistance at low temperature.<br>
The resistance divergence ends at about 3 Kelvin, a behavior recently<br>
demonstrated to arise from the surface conductance. However, questions<br>
remain whether and where a topological surface state exists. Quantum<br>
oscillations have not been observed to map the Fermi surface. We solve<br>
the problem by resolving the Landau Level quantization and Fermi<br>
surface topology using torque magnetometry. The observed angular<br>
dependence of the Fermi surface cross section suggests two-dimensional<br>
surface states on the (101) and (100) plane. Furthermore, similar to<br>
the quantum Hall states for graphene, the tracking of the Landau<br>
Levels in the infinite magnetic field limit points to -1/2, the Berry<br>
phase contribution from the 2D Dirac electronic state. - Host: Vavilov
- Astronomy Colloquium
- The Future of Age: How asteroseismology reveals fundamental properties of Stars like out Sun
- Time: 3:30 pm - 5:00 am
- Place: 4421 Sterling Hall
- Speaker: David Soderblom, Space Telescope Science Institution
- Abstract: Some day fairly soon we can hope to hear an announcement of the signs of life on a planet around another star, and when that happens, our first question will be “How old is that star?” because we will want to place such a discovery in an evolutionary context.But stars do not reveal their ages to us in any direct way and we are left trying to use secondary indicators such as rotation or activity. Asteroseismology offers a real breakthrough in determining stellar ages, particularly for older solar-type stars, and the oscillations detected by Kepler have been especially critical because of their quality and number. In this talk I will present a framework for understanding the problem of stellar age estimation, the limitations encountered with conventional (pre-seismology) methods, how asteroseismology provides constraints on key physical parameters of stars, and what limitations still exist in the problem of estimating stellar ages.
- Graduate Introductory Seminar
- Condensed Matter Experiment and Theory, and Quantum Computing
- Time: 4:30 pm - 5:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Coppersmith, Eriksson, Himpsel, Joynt, McDermott, Onellion, Rzchowski, Saffman, Vavilov, Winokur