The internal Josephson effect in a Fermi gas near a Feshbach resonance

TL;DR

This paper investigates the internal Josephson effect in a Fermi gas near a Feshbach resonance, revealing how phase coherence can lead to oscillations in molecular boson numbers due to tunneling with Cooper pairs.

Contribution

It derives an effective action describing coherent tunneling between molecular bosons and Cooper pairs, highlighting the potential for an internal AC Josephson effect in such systems.

Findings

Derivation of an effective action for Fermi gas near Feshbach resonance.

Prediction of internal AC Josephson oscillations in non-equilibrium.

Analysis of phase coherence and fluctuations in the system.

Abstract

We consider a two-component system of Fermi atoms and molecular bosons in the vicinity of a Feshbash resonance. We derive an effective action for the system, which has a term describing coherent tunneling of the molecular bosons into Cooper pairs and vice versa. In the equilibrium state, global phase coherence may be destroyed by thermal or quantum phase fluctuations. In the non-equilibrium regime, the system may show an internal AC Josephson effect leading to real time oscillations in the number of molecular bosons.