Strongly interacting two-dimensional Fermi gases

TL;DR

This paper reviews the current understanding of two-dimensional Fermi gases with short-range interactions, covering scattering, thermodynamics, pairing, superfluidity, and experimental realizations, emphasizing the effects of quasi-2D geometry.

Contribution

It provides a comprehensive overview of 2D Fermi gases, integrating theoretical insights with recent experimental developments and highlighting the role of quasi-2D effects.

Findings

Analysis of 2D scattering and realization in experiments

Discussion of pairing regimes and superfluid transition

Insights into Fermi polaron and collective modes

Abstract

We review the current understanding of the uniform two-dimensional (2D) Fermi gas with short-range interactions. We first outline the basics of two-body scattering in 2D, including a discussion of how such a 2D system may be realized in practice using an anisotropic confining potential. We then discuss the thermodynamic and dynamical properties of 2D Fermi gases, which cold-atom experiments have only just begun to explore. Of particular interest are the different pairing regimes as the interparticle attraction is varied; the superfluid transition and associated finite-temperature phenomenology; few-body properties and their impact on the many-body system; the Fermi polaron problem; and the symmetries underlying the collective modes. Where possible, we include the contributions from 2D experiment. An underlying theme throughout is the effect of the quasi-2D geometry, which we view as an added richness to the problem rather than an unwanted complication.