Nonclassical light from few emitters in a cavity

TL;DR

This paper investigates the generation of nonclassical light from a few emitters in a cavity under strong coupling, revealing how cooperative effects and emitter number influence photon statistics and the limitations of common theoretical models.

Contribution

It provides a comprehensive analysis of nonclassical light generation in few-emitter cavity systems, including the impact of counter-rotating terms and the failure of standard master equations.

Findings

Cooperative effects enable nonclassical light at lower coupling strengths.

Photon statistics vary between super- and sub-Poissonian regimes depending on parameters.

Standard quantum optical master equations can fail to predict key regimes.

Abstract

We study the characteristics of the light generated by few emitters in a cavity at strong light-matter coupling. By means of the Glauber $g^{(2)}$-function we can identify clearly distinguished parameter regimes with super-Poissonian and sub-Poissonian photon statistics. We establish a relation between the emission characteristics for one and multiple emitters, and explain its origin in terms of the photon-dressed emitter states. Cooperative effects lead to the generation of nonclassical light already at reduced light-matter coupling if the number of emitters is increased. Our results are obtained with a full input-output formalism and master equation valid also at strong light-matter coupling. We compare the behavior obtained with and without counter-rotating light-matter interaction terms in the Hamiltonian, and find that the generation of nonclassical light is robust against such modifications. Finally, we contrast our findings with the predictions of the quantum optical master equation and find that it fails entirely at predicting regimes with different photon statistics.