Collective Excitations of Strongly Interacting Fermi Gases of Atoms in a Harmonic Trap

TL;DR

This paper investigates the collective excitations of strongly interacting Fermi gases in harmonic traps, providing rigorous bounds on their breathing mode frequencies and comparing them with experimental data.

Contribution

It introduces a generalized Hylleraas-Undheim method to establish upper bounds on collective mode frequencies in trapped Fermi gases.

Findings

Derived rigorous upper bounds for collective mode frequencies.

Compared theoretical bounds with experimental data for Li6 atoms.

Validated the hydrodynamic approach for describing collective excitations.

Abstract

The zero-temperature properties of a dilute two-component Fermi gas in the BCS-BEC crossover are investigated. On the basis of a generalization of the Hylleraas-Undheim method, we construct rigorous upper bounds to the collective frequencies for the radial and the axial breathing mode of the Fermi gas under harmonic confinement in the framework of the hydrodynamic theory. The bounds are compared to experimental data for trapped vapors of Li6 atoms.