Zeroth Sound Modes of Dilute Fermi Gas with Arbitrary Spin

TL;DR

This paper investigates the zeroth sound modes in dilute Fermi gases with arbitrary spin, linking their dispersion to Landau parameters and proposing measurements to determine interaction parameters.

Contribution

It introduces a theoretical framework for understanding spin-S excitations in high-spin Fermi gases and relates mode dispersion to measurable scattering lengths.

Findings

Mode dispersion depends on a single Landau parameter

Measurement of modes can determine interaction parameters

Framework applicable to arbitrary spin Fermi gases

Abstract

Motivated by the recent success of optical trapping of alkali bosons, we have studied the zeroth sound modes of dilute Fermi gases with arbitrary spin-f, which are spin-S excitations ($0\leq S\leq 2f$). The dispersion of the mode (S) depends on a single Landau parameter $F^{(S)}$, which is related to the scattering lengths of the system through a simple formula. Measurement of (even a subset of) these modes in finite magnetic fields will enable one to determine all the interaction parameters of the system.