Nonhydrodynamic Transport in Trapped Unitary Fermi Gases

Phys Rev Lett. 2015 Nov 6;115(19):190404. doi: 10.1103/PhysRevLett.115.190404. Epub 2015 Nov 5.

Abstract

Many strongly coupled fluids are known to share similar hydrodynamic transport properties. In this work we argue that this similarity could extend beyond hydrodynamics to transient dynamics through the presence of nonhydrodynamic modes. We review nonhydrodynamic modes in kinetic theory and gauge-gravity duality and discuss their signatures in trapped Fermi gases close to unitarity. Reanalyzing previously published experimental data we find hints of nonhydrodynamic modes in cold Fermi gases in two and three dimensions.