Photonic Bose-Einstein condensation in the continuum limit

TL;DR

This paper explores photon Bose-Einstein condensation as mode spacing approaches zero, revealing a second threshold and detailed mode occupation behavior near the continuum limit.

Contribution

It introduces the concept of a second threshold in photon BEC at small mode spacings and analyzes mode occupations near the continuum limit.

Findings

Identification of a second threshold for condensation at small mode spacings

Detailed analysis of mode occupations in the precondensate region

Insights into the crossover to a fully condensed state

Abstract

We investigate the properties of the photon Bose-Einstein condensate in the limit of small mode spacing. Alongside the well-known threshold of the phase transition at large mode spacings, we find an emergence of a second threshold for sufficiently small mode spacings, defining the crossover to a fully condensed state. Furthermore, we present our findings for the mode occupations in the precondensate or supercooling region towards the continuum limit.