Quantum phases of spinful Fermi gases in optical cavities

TL;DR

This paper investigates the diverse quantum phases of spinful fermionic atoms in one-dimensional optical cavities, revealing spin and density wave orderings, superfluidity, and the influence of photon-mediated long-range interactions.

Contribution

It introduces a comprehensive analysis of quantum phases in spinful Fermi gases with tunable photon-mediated interactions, combining mean-field, exact diagonalization, and bosonization methods.

Findings

Spin and density wave orderings emerge in the system.

Superfluidity appears for positive interaction strength g.

Photon-mediated interactions induce strong correlations with fermionic or bosonic character depending on g.

Abstract

We explore the quantum phases emerging from the interplay between spin and motional degrees of freedom of a one-dimensional quantum fluid of spinful fermionic atoms, effectively interacting via a photon-mediating mechanism with tunable sign and strength g, as it can be realized in present-day experiments with optical cavities. We find the emergence, in the very same system, of spin- and atomic-density wave ordering, accompanied by the occurrence of superfluidity for g > 0, while cavity photons are seen to drive strong correlations at all g values, with fermionic character for g > 0, and bosonic character for g < 0. Due to the long-range nature of interactions, to infer these results we combine mean-field and exact diagonalization methods supported by bosonization analysis.