Pattern Formation and Strong Nonlinear Interactions in Exciton-Polariton Condensates

TL;DR

This paper develops a predictive theoretical framework for exciton-polariton condensates, explaining pattern formation, thresholds, and interactions based on linear non-Hermitian modes, aligning with recent experimental observations.

Contribution

It introduces an analytic approach using non-Hermitian modes to predict thresholds and patterns in exciton-polariton condensates, advancing beyond previous numerical methods.

Findings

Analytic expression for condensation thresholds

Geometry-dependent evolution of condensate patterns

Explanation of experimental modal patterns

Abstract

Exciton-polaritons generated by light-induced potentials can spontaneously condense into macroscopic quantum states that display nontrivial spatial and temporal density modulation. While these patterns and their dynamics can be reproduced through the solution of the generalized Gross-Pitaevskii equation, a predictive theory of their thresholds, oscillation frequencies, and multi-pattern interactions has so far been lacking. Here we represent such an approach based on the linear non-Hermitian modes of the complex-valued light-induced potential. We provide a simple analytic expression for the lowest thresholds that is able to explain the modal patterns observed in recent experiments for various pump geometries. We also show that the evolution of the condensate with increasing pump strength is strongly geometry dependent and can display contrasting features such as enhancement or reduction of the spatial localization of the condensate.