Phases of a bilayer Fermi gas

TL;DR

This paper explores a two-species bilayer Fermi gas system, revealing a complex phase diagram with various pairing and condensation phases, and demonstrates a method to induce long-range correlations in ultracold atomic gases.

Contribution

It introduces a novel bilayer Fermi gas model with tunable interactions, analyzing its phase diagram and identifying multiple exotic phases and stable Efimov-like trimers.

Findings

Identification of interlayer s-wave and intralayer p-wave pairing phases

Discovery of a dimer Bose-Einstein condensate phase

Existence of stable Efimov-like trimers in the system

Abstract

We investigate a two-species Fermi gas in which one species is confined in two parallel layers and interacts with the other species in the three-dimensional space by a tunable short-range interaction. Based on the controlled weak coupling analysis and the exact three-body calculation, we show that the system has a rich phase diagram in the plane of the effective scattering length and the layer separation. Resulting phases include an interlayer s-wave pairing, an intralayer p-wave pairing, a dimer Bose-Einstein condensation, and a Fermi gas of stable Efimov-like trimers. Our system provides a widely applicable scheme to induce long-range interlayer correlations in ultracold atoms.