Shear viscosity and damping for a Fermi gas in the unitarity limit

Abstract

The shear viscosity of a two-component Fermi gas in the normal phase is calculated as a function of temperature in the unitarity limit, taking into account strong-coupling effects that give rise to a pseudogap in the spectral density for single-particle excitations. The results indicate that recent measurements of the damping of collective modes in trapped atomic clouds can be understood in terms of hydrodynamics, with a decay rate given by the viscosity integrated over an effective volume of the cloud.

Comments: 7 pages, 3 figures. Discussion significantly extended. Appendix added. To appear in PRA