Anisotropic sound propagation in dilute dipolar gases.

Ultracold dipolar gases have garnered extensive interest in recent years, attributed to their capacity for a rich variety of dynamical phenomena. One such instance is anisotropic scattering, dominant in thermal dipolar gases in the quantum collision regime. When taken out of equilibrium, this anisotropy can lead to axially differentiated spreading of energy through the gas. To this end, we study how dipolar collisions lead to an anisotropic viscosity that distorts acoustic wave propagation. The implications to diffusive transport are addressed, and extensions to this work are proposed. Analysis is performed with a semi-analytic theory based on the Enskog formalism, verified by numerical Monte Carlo simulations. This work is funded by the NSF.