Universal Density Shift Coefficients for the Thermal Conductivity and Shear Viscosity of a Unitary Fermi Gas

Abstract

We measure universal temperature-independent density shifts for the thermal conductivity $\hat{I}{º}_T$ and shear viscosity $\hat{I}\cdot$, relative to the high temperature limits, for a normal phase unitary Fermi gas confined in a box potential. We show that a time-dependent kinetic theory model enables extraction of the hydrodynamic transport times $\ddot{I}{„}_{\hat{I}}\cdot$ and $\ddot{I}{„}_{\hat{I}}º$ from the time-dependent free-decay of a spatially periodic density perturbation, yielding the static transport properties and density shifts, corrected for finite relaxation times.

15 pages 12 figures