Emergent thermal fluctuations and non-Hermitian phase transitions in open photon condensates
Abstract
We investigate the nonequilibrium dynamics of an open photon Bose-Einstein condensate in a dye-filled microcavity using a Lindblad master-equation approach, treating the condensate and the noncondensed fluctuations on the same footing. The driven-dissipative condensate exhibits a long-lived, metastable plateau stabilized by a ghost attractor, a fixed point that lies outside the physical domain in configuration space, yet stalls the condensate dynamics for exceedingly long times before it dephases to zero [Phys. Rev. Lett. 135, 053402 (2025)]. Despite the nonequilibrium origin of this dynamical stabilization, the condensate exhibits quasithermal fluctuations in the plateau in that the relative order-parameter fluctuations scale as the inverse square root of the system size. A linear stability analysis further reveals the presence of exceptional points, resulting in multiple non-Hermitian phase transitions associated with the relaxation dynamics into and out of the metastable condensate.
Keywords
Cite
@article{arxiv.2603.21927,
title = {Emergent thermal fluctuations and non-Hermitian phase transitions in open photon condensates},
author = {Moritz Janning and Roman Kramer and Michael Turaev and Sayak Ray and Johann Kroha},
journal= {arXiv preprint arXiv:2603.21927},
year = {2026}
}
Comments
8 pages, 8 figures