Quantum Treatment for Bose-Einstein Condensation in Non-Equilibrium Systems

TL;DR

This paper introduces a stochastic quantum trajectory approach to study non-equilibrium Bose-Einstein condensation, revealing coherence properties and phase transitions in exciton polaritons within semiconductor microcavities.

Contribution

The paper presents a novel stochastic quantum trajectory method to analyze coherence and condensation phenomena in non-equilibrium bosonic systems.

Findings

Observation of macroscopic occupation in the lowest-energy mode

Transition from thermal to coherent temporal coherence

Development of off-diagonal long-range order in spatial coherence

Abstract

We develop an approach based on stochastic quantum trajectories for an incoherently pumped system of interacting bosons relaxing their energy in a thermal reservoir. Our approach enables the study of the versatile coherence properties of the system. We apply the model to exciton polaritons in a semiconductor microcavity. Our results demonstrate the onset of macroscopic occupation in the lowest-energy mode accompanied by the establishment of both temporal and spatial coherence. We show that temporal coherence exhibits a transition from a thermal to coherent statistics and the spatial coherence reveals off-diagonal long-range order.