Note on Bose-Einstein condensation of photons

TL;DR

This paper offers a concise mathematical derivation of photon Bose-Einstein condensation, extends previous results with new insights on the condensate function, and applies the framework to explain experimental findings, suggesting broader experimental possibilities.

Contribution

It provides a new theoretical framework for photon BEC, including derivations, new results, and a consistent explanation of experiments, expanding potential experimental setups.

Findings

Derivation of photon BEC including new condensate function results

Application of theory to explain experimental observations from 2010

Proposal for wider experimental frameworks beyond dye media

Abstract

This paper provides, firstly, a succinct mathematical derivation of Bose-Einstein condensation (BEC) of photons elaborating on previous results [M\"uller, E.E., Annals of Phys. 184, 219-230 (1988); M\"uller, E.E. Physica 139A, 165-174 (1986)] including new results on the condensate function, and, secondly, applies this framework to consistently explain experimental findings reported in Klaers J., Schmitt, J., Vewinger, F & Weitz, M., Nature 468, 545-548 (2010). The theoretical approach presented here invites to significantly widen the experimental framework for BEC of photons including three-dimensional photon resonators and thermalization mechanisms different from a dye medium in the cavity.