4th Annual Dasari Lecture

John Thomas, Duke University

A Tale of Quantum Viscosity in Universal Fermi Gases

Tuesday, November 9, 2010
12:00 noon - 1:00 p.m. Grier Room (34-401)

An optically-trapped mixture of spin ½-up and spin ½-down ⁶Li atoms provides a unique paradigm for exploring strongly interacting Fermi systems in nature. This ultracold atomic gas offers unprecedented opportunities to test theoretical techniques that cross interdisciplinary boundaries. A bias magnetic field is used to tune the gas to a Feshbach resonance, where the s-wave scattering length diverges, so that the interparticle spacing and thermal de Broglie wavelength set the only length scales, making the system universal. Even though it is dilute, an atomic Fermi gas near a Feshbach resonance is the most strongly interacting nonrelativistic system known, enabling tests of recent theories in disciplines from high temperature superconductors to nuclear matter. I will describe our recent measurements of universal viscosity in a resonantly interacting Fermi gas and compare the ratio of the shear viscosity to the entropy density to that of a perfect fluid.

Indian food will be served following the seminar.

Co-sponsored by the George R. Harrison Spectroscopy Laboratory and the Department of Chemistry, Massachusetts Institute of Technology.