Signatures of macroscopic quantum coherence in ultracold dilute Fermi gases

TL;DR

This paper proposes a double-well optical trap setup for ultracold Fermi-Bose mixtures to detect macroscopic quantum coherence associated with superfluidity, using tunneling and interference signatures.

Contribution

It introduces a novel experimental configuration and methods to observe superfluid signatures in ultracold Fermi gases through tunneling and interference phenomena.

Findings

Identification of tunneling of Fermi pairs as a superfluid signature

Observation of interference fringes in separated potential minima

Feasibility of low decoherence times with optimized trapping techniques

Abstract

We propose a double-well configuration for optical trapping of ultracold two-species Fermi-Bose atomic mixtures. Two signatures of macroscopic quantum coherence attributable to a superfluid phase transition for the Fermi gas are analyzed. The first signature is based upon tunneling of Fermi pairs when the power of the deconfining laser beam is significantly reduced. The second relies on the observation of interference fringes in a regime where the fermions are trapped in two sharply separated minima of the potential. Both signatures rely on small decoherence times for the Fermi samples, which should be possible by reaching low temperatures using a Bose gas as a refrigerator, and a bichromatic optical dipole trap for confinement, with optimal heat-capacity matching between the two species.