Higher first Chern numbers in one dimensional Bose-Fermi mixtures

TL;DR

This paper proposes a one-dimensional Bose-Fermi mixture system with periodic driving to realize topological superfluid phases with Chern numbers greater than 1, specifically Chern number ±2, which are stable under certain conditions.

Contribution

It introduces a novel setup using driven lattice fermions and bosons to achieve higher Chern number superfluid phases, with a simple formula for analyzing topological properties.

Findings

Superfluid with Chern number ±2 can be realized under specific conditions.

The phase is stable across a broad range of parameters.

Cold atomic gases can implement the proposed system.

Abstract

We propose to use a one-dimensional system consisting of identical fermions in a periodically driven lattice immersed in a Bose gas, to realise topological superfluid phases with Chern numbers larger than 1. The bosons mediate an attractive induced interaction between the fermions, and we derive a simple formula to analyse the topological properties of the resulting pairing. When the coherence length of the bosons is large compared to the lattice spacing and there is a significant next-nearest neighbour hopping for the fermions, the system can realise a superfluid with Chern number +/- 2. We show that this phase is stable in a large region of the phase diagram as a function of the filling fraction of the fermions and the coherence length of the bosons. Cold atomic gases offer the possibility to realise the proposed system using well-known experimental techniques.