Nonequilibrium phase transition in a spin-1 Dicke model

Abstract

The Dicke model is a paradigm of collective behavior in quantum mechanics describing an ensemble of two-level atoms interacting with a single mode of the electromagnetic field. Here we simulate a spin-1 Dicke model using magnetic sublevels of the lowest =1 hyperfine level of 87Rb atoms confined to a high finesse cavity. Our implementation enables simple tuning of the model parameters over a large parameter space. We study this system under conditions of imbalanced driving, which is predicted to have a rich phase diagram of nonequilibrium phases and phase transitions. Exploring the system over a wide range of parameters, we obtain boundaries between normal, super-radiant, and oscillatory phases, and compare with a simple theoretical model. This study provides further understanding of the fundamental nature of the model and has technological applications such as superradiant lasers and storage of quantum information in collective atomic states.