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

TL;DR

This paper calculates the shear viscosity of a strongly interacting Fermi gas in the unitarity limit, incorporating pseudogap effects, and relates these findings to experimental damping measurements in trapped atomic gases.

Contribution

It introduces a detailed calculation of shear viscosity including pseudogap effects and connects theoretical results with experimental damping data.

Findings

Viscosity varies with temperature in the unitarity limit.

Hydrodynamic damping rates align with experimental measurements.

Strong-coupling effects significantly influence spectral properties.

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.