Dicke Transition in Open Many-Body Systems Determined by Fluctuation Effects

We develop an approach to describe the Dicke transition of interacting many-particle systems strongly coupled to the light of a lossy cavity. A mean-field approach is combined with a perturbative treatment of fluctuations beyond mean field, which becomes exact in the thermodynamic limit. These fluctuations completely change the nature of the steady state, determine the thermal character of the transition, and lead to universal properties of the emerging self-organized states. We validate our results by comparing them with time-dependent matrix-product-state calculations.

Automated summary

In this study, we proposed an approach to describe the Dicke transition of interacting many-particle systems strongly coupled to the light of a lossy cavity. By combining a mean-field approach with a perturbative treatment of fluctuations, we were able to determine the nature of the steady state, the thermal character of the transition, and the universal properties of the emerging self-organized states. Our results were validated through comparisons with time-dependent matrix-product-state calculations.