First-order superfluid-Mott-insulator transition for quantum optical switching in cavity QED arrays with two cavity modes

TL;DR

This paper theoretically explores phase transitions in cavity QED arrays with two photon modes, revealing a first-order superfluid-Mott insulator transition under specific conditions, which could inform future quantum optical switching device design.

Contribution

It identifies and explains the first-order superfluid-Mott insulator transition in cavity QED arrays with two photon modes, a phenomenon not previously characterized in this context.

Findings

First-order phase transition occurs under specific emitter models.

Discontinuous change in emitter states accompanies the transition.

Conditions for the transition provide design insights for quantum optical switches.

Abstract

We theoretically investigated the ground states of coupled arrays of cavity quantum electrodynamical (cavity QED) systems in presence of two photon modes. Within the Gutzwiller-type variational approach, we found the first-order quantum phase transition between Mott insulating and superfluid phases as well as the conventional second-order one. The first-order phase transition was found only for specific types of emitter models, and its physical origin is clarified based on the analytic arguments which are allowed in the perturbative and semiclassical limits. The first-order transition of the correlated photons is accompanied with discontinuous change in the emitter states, not only with the appearance of inter-cavity coherence in the superfluid phase. We also discuss the condition for the first-order transition to occur, which can lead to a strategy for future design of quantum optical switching devices with cavity QED arrays.