Microscopic Theory of Equilibrium Polariton Condensates

TL;DR

This paper develops a microscopic theory for equilibrium polariton condensates in semiconductor quantum wells, revealing weaker interactions, smaller exciton fractions, and tunable Rabi coupling, with implications for electrical control of condensates.

Contribution

It introduces a detailed microscopic framework that refines understanding of polariton condensates, including interaction strengths and controllability, beyond simplified models.

Findings

Polariton-polariton interactions are weaker than in simplified models.

Condensate exciton fractions are smaller than previously estimated.

Effective Rabi coupling depends on cavity photon detuning.

Abstract

We present a microscopic theory of the equilibrium polariton condensate state of a semiconductor quantum well in a planar optical cavity. The theory accounts for the adjustment of matter excitations to the presence of a coherent photon field, predicts effective polariton-polariton interaction strengths that are weaker and condensate exciton fractions that are smaller than in the commonly employed exciton-photon model, and yields effective Rabi coupling strengths that depend on the detuning of the cavity photon energy relative to the bare exciton energy. The dressed quasiparticle bands that appear naturally in the theory provide a mechanism for electrical manipulation of polariton condensates.