Nonequilibrium phase transitions and pattern formation in photon condensates

Himadri_Shekhar Dhar

Indian Institute of Technology Bombay, India -

In recent years, condensates of light in dye-filled microcavities have become an ideal platform to study many-body phenomena. In this poster we look at two important results related to the emergence of collective and nonequilibrium properties in photon condensates. First, we look at the different phases in photonic condensates consisting of only a few photons. With the help of machine learning we are able to create a fuzzy phase diagram, which reflects the existence of collective behaviour away from the thermodynamic limit. Second, we explore to what extent a transient photonic condensate can exhibit macroscopic coherence resembling that of a vortex. By exciting the system with an orbiting pump spot, spatial patterns with discrete rotational symmetry are observed, controlled by the orbital frequency of the pump spot. Importantly, calculation of the correlation function shows a vortex-like phase coherence in the pattern, despite the absence of any effective photon-photon interaction.

Related paper: https://arxiv.org/abs/2006.12298; https://arxiv.org/abs/2104.11002