Thermalization regimes in a chaotic Tavis-Cummings model.

This work investigates the emergent thermalization regimes in a chaotic Tavis-Cummings (TC) model and their implications in quantum spectroscopy. While the TC model is a cornerstone of cavity quantum electrodynamics, traditional treatments often overlook many-body effects that arise in the thermodynamic limit. We utilize the eigenstate thermalization hypothesis to demonstrate that a nonintegrable excitonic Hamiltonian within the material manifold drives local thermalization. By tuning the polariton splitting g, we observe two dynamical regimes: a thermalizing regime at low interactions driven by quantum chaos and ergodicity, and a nonthermalizing regime at high interactions where strong coupling suppresses ergodicity. We further show that these regimes have direct implications on output photon statistics, specifically influencing the correlation times τc of the cavity population and the second-order correlation function g(2) (t + τ). We propose that entangled-biphoton spectroscopy serves as an ideal experimental platform to probe these effects and to allow the characterization of the underlying many-body exciton-coupling disorder σ through coincidence measurements of the output. Taken together, these results exploit a naturally occurring many-body phenomenon to bridge theoretical predictions with experimental observables.