Zero sound in a two-dimensional dipolar Fermi gas

TL;DR

This paper investigates zero sound propagation in a two-dimensional dipolar Fermi gas, highlighting the roles of mean field and many-body effects, anisotropic sound velocity, and potential experimental observability despite damping challenges.

Contribution

It provides a theoretical analysis of zero sound in 2D dipolar Fermi gases, including anisotropy and damping, extending understanding beyond previous models.

Findings

Zero sound propagation is supported by both mean field and many-body effects.

The anisotropy of zero sound velocity matches that of the Fermi velocity.

Zero sound damping can be slower than quasiparticle damping, aiding experimental detection.

Abstract

We study zero sound in a weakly interacting 2D gas of single-component fermionic dipoles (polar molecules or atoms with a large magnetic moment) tilted with respect to the plane of their translational motion. It is shown that the propagation of zero sound is provided by both mean field and many-body (beyond mean field) effects, and the anisotropy of the sound velocity is the same as the one of the Fermi velocity. The damping of zero sound modes can be much slower than that of quasiparticle excitations of the same energy. One thus has wide possibilities for the observation of zero sound modes in experiments with 2D fermionic dipoles, although the zero sound peak in the structure function is very close to the particle-hole continuum.