Experimental Observation of Thermalisation in a Nonlinear Non-Hermitian Optical Lattice

Nonlinear multimoded systems have always been a challenge to describe theoretically due to their high complexity. In recent years, significant progress has been made in adapting methods from statistical physics and thermodynamics to an optical framework to enable a comprehensive theoretical description and deeper understanding of such systems [1]–[3]. While initially developed in the context of Hermitian configurations, this description has recently been extended to include non-Hermitian settings as well [4]. However, so far, the interesting dynamics predicted in [4] have not been implemented in any optical platform. Our work closes this gap by presenting the first experimental observation of thermalisation in a nonlinear non-Hermitian optical system.