Theory of Bose-Einstein Condensation of Light in a Microcavity

TL;DR

This paper develops a comprehensive theory for Bose-Einstein condensation of light in a dye microcavity, accounting for polarization degeneracy and interactions, and extends understanding across all regimes of photon and dye molecule numbers.

Contribution

It introduces a general theoretical framework that surpasses the grand canonical approximation, describing microscopic to macroscopic light BEC with a universal coherence relation.

Findings

Derived a universal relation between coherence degrees of photon and polarized condensates.

Provided a detailed statistical description of light BEC across all temperature and particle number regimes.

Showed potential of photon BEC as a source of nonclassical light.

Abstract

A theory of Bose-Einstein condensation (BEC) of light in a dye microcavity is developed. The photon polarization degeneracy and the interaction between dye molecules and photons in all of the cavity modes are taken into account. The theory goes beyond the grand canonical approximation and allows one to determine the statistical properties of the photon gas for all numbers of dye molecules and photons at all temperatures, thus describing the microscopic, mesoscopic, and macroscopic light BEC from a general perspective. A universal relation between the degrees of second-order coherence for the photon condensate and the polarized photon condensate is obtained. The photon Bose-Einstein condensate can be used as a new source of nonclassical light.