Anisotropic acoustics in dipolar Fermi gases

We consider plane wave modes in ultracold, but not quantum degenerate, dipolar Fermi gases in the hydrodynamic limit. Longitudinal waves present anisotropies in both the speed of sound and their damping, and experience a small, undulatory effect in their flow velocity. Two distinct types of shear waves appear, a familiar one, and another that is accompanied by nontrivial density and temperature modulations. We propose these shear modes as an experimental means to measure the viscosity coefficients, including their anisotropies.

Automated summary

In this paper, we investigate plane wave modes in ultracold, non-quantum degenerate, dipolar Fermi gases under the hydrodynamic limit. Longitudinal waves exhibit anisotropies in both their speed of sound and damping, as well as a small undulatory effect in their flow velocity. Two distinct types of shear waves are observed, one being familiar and the other accompanied by nontrivial density and temperature modulations. We propose using these shear modes as an experimental approach to measure the viscosity coefficients, including their anisotropies.