Edge singularities and quasi-long-range order in non-equilibrium steady states

TL;DR

This paper demonstrates that non-equilibrium steady states in one-dimensional Bose gases exhibit edge singularities and quasi-long-range order, even at finite temperatures where these features are absent in equilibrium.

Contribution

It reveals that non-equilibrium protocols can induce edge singularities and preserve quasi-long-range order in 1D Bose gases at finite temperature.

Findings

Edge singularities appear in the response function of non-equilibrium steady states.

Quasi-long-range order persists in the non-equilibrium steady state.

Finite temperature effects are mitigated in the non-equilibrium setting.

Abstract

The singularities of the dynamical response function are one of the most remarkable effects in many-body interacting systems. However in one dimension these divergences only exist strictly at zero temperature, making their observation very difficult in most cold atomic experimental settings. Moreover the presence of a finite temperature destroys another feature of one-dimensional quantum liquids: the real space quasi-long-range order in which the spatial correlation functions exhibit power-law decay. We consider a non-equilibrium protocol where two interacting Bose gases are prepared either at different temperatures or chemical potentials and then joined. We show that the non-equilibrium steady state emerging at large times around the junction displays edge singularities in the response function and quasi-long-range order.