Composite fermion state of spin-orbit coupled bosons

TL;DR

This paper proposes that a 2D spinor Bose gas with Rashba spin-orbit coupling at low density forms a composite fermion state with a Chern-Simons gauge field, which has lower energy than previous candidate states.

Contribution

It introduces a novel ground state for spin-orbit coupled bosons, demonstrating the formation of a composite fermion state with specific energetic advantages.

Findings

The ground state is a composite fermion with a Chern-Simons gauge field.

The chemical potential scales as rac{n^{3/2}}.

This state has lower energy than condensate or spin density wave states.

Abstract

We consider spinor Bose gas with the isotropic Rashba spin-orbit coupling in 2D. We argue that at low density its groundstate is a composite fermion state with a Chern-Simons gauge field and filling factor one. The chemical potential of such a state scales with the density as \mu \propto n^{3/2}. This is a lower energy per particle than \mu \propto n for the earlier suggested groundstate candidates: a condensate with broken time-reversal symmetry and a spin density wave state.