Mainz 2026 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 46: Open Quantum Systems II

Q 46.2: Talk

Thursday, March 5, 2026, 11:30–11:45, P 4

From lasers to photon Bose–Einstein condensates: A unified description via an open-dissipative Bose–Einstein distribution — •Joshua Krauß, Enrico Stein, and Axel Pelster — Physics Department and Research Center OPTIMAS, RPTU Kaiserslautern-Landau, Kaiserslautern, Germany

Photon condensation was first observed in 2010 within a dye-filled microcavity at room temperature [1] and gained interest since then. In this study we examine how the driven-dissipative nature of a photon Bose–Einstein condensate modifies the condensation process [2]. To this end, we consider a rate-equation model, which can be derived microscopically [3–5]. It depends on external parameters such as emission and absorption rates as well as cavity photon losses [6]. In steady state, the photon occupation follows an open-dissipative Bose–Einstein distribution whose chemical potential is set self-consistently by the dye’s ground- and excited-state populations. We show that driven-dissipative parameters strongly alter the distribution and use these results to distinguish photonic condensation from both atomic condensation and lasing [2].

[1] J. Klaers et alii, Nature 468, 545 (2010)

[2] J. Krauß et alii, ArXiv:2510.05917 (2025)

[3] P. Kirton and J. Keeling, Phys. Rev. Lett. 111, 100404 (2013)

[4] M. Radonjić et alii, New J. Phys. 20, 055014 (2018)

[5] E. Stein, PhD. Thesis, TU Kaiserslautern, (2022)

[6] J. Schmitt et alii, Zenodo, DOI: 10.5281/zenodo.10852935 (2024)

Keywords: Rate Equation; Photon Bose-Einstein Condensate; Laser; Multimode Model; Open-Dissipative