Thermodynamics and linear response of a Bose-Einstein condensate of microcavity polaritons

TL;DR

This paper develops a comprehensive theoretical framework for Bose-Einstein condensation of microcavity polaritons, incorporating interactions and coupling effects, and predicts the system's spectral response consistent with experimental data.

Contribution

It generalizes the Hartree-Fock-Popov theory to coupled Bose fields, providing a self-consistent description of polariton condensation and response.

Findings

Quantitative agreement with experimental phase diagrams

Predictions of spectral response to external perturbations

Computed density-dependent spectra and occupations

Abstract

In this work we derive a theory of polariton condensation based on the theory of interacting Bose particles. In particular, we describe self-consistently the linear exciton-photon coupling and the exciton-nonlinearities, by generalizing the Hartree-Fock-Popov description of BEC to the case of two coupled Bose fields at thermal equilibrium. In this way, we compute the density-dependent one-particle spectrum, the energy occupations and the phase diagram. The results quantitatively agree with the existing experimental findings. We then present the equations for the linear response of a polariton condensate and we predict the spectral response of the system to external optical or mechanical perturbations.