Trapped Phase-Segregated Bose-Fermi Mixtures and their Collective Excitations

TL;DR

This paper theoretically investigates the collective excitations of phase-segregated Bose-Fermi mixtures at zero temperature, revealing how mode frequencies evolve with particle composition and identifying damping caused by interface-driven fermions.

Contribution

It provides a detailed theoretical analysis of collective modes in phase-segregated Bose-Fermi mixtures, highlighting the impact of particle ratio on excitation frequencies and damping mechanisms.

Findings

Mode frequencies interpolate between bosonic and fermionic limits as fermion fraction increases.

Damping occurs due to resonant driving of fermions at the interface.

Frequencies and damping depend on the fermion-to-boson particle ratio.

Abstract

Recent progress in the field of ultracold gases has allowed the creation of phase-segregated Bose-Fermi systems. We present a theoretical study of their collective excitations at zero temperature. As the fraction of fermion to boson particle number increases, the collective mode frequencies take values between those for a fully bosonic and those for a fully fermionic cloud, with damping in the intermediate region. This damping is caused by fermions which are resonantly driven at the interface.