Resonant superfluidity in the Rabi-coupled spin-dependent Fermi-Hubbard model

TL;DR

This paper explores how Rabi coupling influences superfluidity in a one-dimensional attractive Fermi-Hubbard model, revealing resonant enhancement of pair superfluidity near certain coupling strengths.

Contribution

It demonstrates the resonant enhancement of pair superfluidity due to Rabi coupling and derives an effective spin model to explain the ground-state properties.

Findings

Resonant superfluidity enhancement occurs near Rabi coupling comparable to interaction strength.

Even with one immobile component, superfluidity can be significantly enhanced.

Effective spin-1/2 XXZ model explains the ground-state behavior.

Abstract

We investigate the ground-state phase diagram of the one-dimensional attractive Fermi-Hubbard model with spin-dependent hoppings and an on-site Rabi coupling using the density matrix renormalization group method. In particular, we show that even in the limit of one component being immobile the pair superfluidity can be resonantly enhanced when the Rabi coupling is on the order of the interaction strength just before the system starts to strongly polarize. We derive an effective spin-1/2 XXZ model in order to understand the ground-state properties in the strong attraction limit.