Spectral and Thermodynamical properties of non-Hermitian Photon Gases

Abstract

We present a study of the spectral and thermodynamic properties of non-Hermitian photon gases, with a particular focus on the impact of loss engineering in tight-binding models. The scope of applications of these systems is multifold. First, we show theoretically and experimentally the existence of topological monomodes in non-Hermitian SSH models (in 1D and 2D) created by loss engineering. This challenges the idea that edge states always come in pairs in Z2 symmetry-protected topological systems. Then we explore the quantum metric tensor, which gives a geometric interpretation to the Hilbert space in which states live. We produce phase diagrams for the given models and confirm that these are in agreement with known literature. Finally, we explore the occurrence of an imaginary time crystal phase in these systems, by studying the two-point correlation functions and the behaviour of thermodynamical properties. This analysis offers theoretical predictions that can be experimentally validated to confirm the existence of this intriguing phase of matter.