Bosons in fluctuating gauge fields: Bose metal and phase separation

TL;DR

This paper investigates a 2D bosonic system coupled to a fluctuating gauge field, revealing instabilities leading to phase separation and a Bose metal phase, with implications for the t--J model.

Contribution

It identifies conditions under which a Bose metal and phase separation occur due to gauge field fluctuations in a 2D bosonic system.

Findings

Instability to phase separation at T=0

Emergence of a homogeneous Bose metal phase

Dependence of instabilities on gauge field propagator form

Abstract

We study a two-dimensional system of bosons interacting with a fluctuating U(1) gauge field with overdamped dynamics. We find two instabilities of the condensed phase at T=0: one to phase separation and another to a homogeneous non-superfluid (Bose metal). The presence of both instabilities in the model is dependent on the low-energy form of the gauge field propagator. We discuss the relevance of our findings to the U(1) gauge theory of the t--J model.