Laser from a Manybody Correlated Medium

TL;DR

This paper investigates how a non-equilibrium many-body system of interacting emitters coupled to a cavity can produce laser light, with the output sensitive to the interplay between interactions and hopping, revealing unique correlation behaviors.

Contribution

It demonstrates that the laser output and correlations depend on the ratio of interaction to hopping, highlighting non-equilibrium effects in the XXZ model coupled to a cavity.

Findings

Maximal laser output occurs at the Heisenberg point ($U=J$).

Charge-charge correlations depend on the interaction-hopping ratio.

Different magnetic correlations emerge depending on the ratio, contrasting equilibrium behavior.

Abstract

We consider a non-equilibrium system of interacting emitters described by the XXZ model, whose excitonic transitions are spatially and spectrally coupled to a single mode cavity. We demonstrate that the output radiation field is sensitive to an interplay between the hopping ($J$) and the interactions ($U$) of the excitons. Moderate values of the short-ranged interaction are shown to induce laser with maximal output at the Heisenberg point ($U=J$). In the laser regime, charge-charge correlations emerge and they are shown to strongly depend on the interaction-hopping ratio. In particular, the system shows charge-density correlations below the Heisenberg point and ferromagnetic correlations beyond the Heisenberg point. This contrast to the equilibrium behavior of the XXZ chain occurs since the laser explores highly excited states of the emitters.