Events at Physics |
Events on Thursday, December 18th, 2014
- R. G. Herb Condensed Matter Seminar
- Hydrodynamic Coulomb and Hall drag of strongly correlated electron liquids
- Time: 10:00 am - 11:00 am
- Place: Chamberlin 5310
- Speaker: Alex Levchenko, Michigan State University
- Abstract: We develop a theory of drag resistivity in ultraclean double layers with strongly correlated carriers. In the regime where the equilibration length of the electron liquid is shorter than the interlayer spacing the main contribution to the drag arises from hydrodynamic density fluctuations. The latter consist of plasmons driven by fluctuating longitudinal stresses, and diffusive modes caused by temperature fluctuations and thermal expansion of the electron liquid. We express the drag resistivity tensor in terms of the kinetic coefficients of the electron fluid. Our results are nonperturbative in interaction strength and do not assume Fermi-liquid behavior of the electron liquid.
- Host: Vavilov
- NPAC (Nuclear/Particle/Astro/Cosmo) Forum
- An Effective Field Theory Analysis of the LUX WIMP Search
- Time: 2:30 pm - 3:30 pm
- Place: 5280 Chamberlin Hall
- Speaker: Nicole Larsen, Yale University
- Abstract: The Large Underground Xenon (LUX) experiment is a dark matter direct detection experiment located 4850 feet underground at the Sanford Underground Research Facility in Lead, SD. During Summer 2013, LUX collected 10065 kg-days of WIMP search data. Ultimately LUX reported a minimum cross-section limit for spin-independent WIMP-nucleon elastic scattering of 7.6 e-46 cm2 for 33-GeV WIMPs, making it the most sensitive direct detection experiment to date. Direct detection experiments like LUX typically only present limits on spin-independent (SI) and spin-dependent (SD) WIMP-nucleon interaction cross sections. However, recent theoretical work has emphasized that in the most general effective field theory formulation there are several additional momentum-dependent and velocity-dependent interactions allowed by basic symmetries that can interfere with or modify the standard SI and SD interactions. Moreover, entirely new nuclear responses analogous to angular-momentum-dependent and spin-orbit couplings in standard weak interaction theory can emerge. Here I provide an overview of the LUX detector and last year’s WIMP search run, discuss the current status of the experiment, and highlight recent efforts toward using the LUX 2013 dataset to set limits on these new momentum- and velocity-dependent operators.
- Host: Westerhoff