Coherence properties of the microcavity polariton condensate

TL;DR

This paper presents a theoretical model explaining the dominant decoherence process in microcavity polariton condensates, highlighting the role of self-phase modulation and its impact on phase coherence decay and intensity correlations.

Contribution

It introduces a model that links number fluctuations to phase decoherence, predicting decay behaviors and connecting theoretical insights with experimental observations.

Findings

Phase coherence decay follows a Kubo form, Gaussian or exponential.

Decay rate of g2(t) is determined by fluctuation rate.

Model explains recent experimental measurements and predicts regimes with slower decay.

Abstract

A theoretical model is presented which explains the dominant decoherence process in a microcavity polariton condensate. The mechanism which is invoked is the effect of self-phase modulation, whereby interactions transform polariton number fluctuations into random energy variations. The model shows that the phase coherence decay, g1(t), has a Kubo form, which can be Gaussian or exponential, depending on whether the number fluctuations are slow or fast. This fluctuation rate also determines the decay time of the intensity correlation function, g2(t), so it can be directly determined experimentally. The model explains recent experimental measurements of a relatively fast Gaussian decay for g1(t), but also predicts a regime, further above threshold, where the decay is much slower.