Non-equilibrium phase transition in a spin-1 Dicke model

TL;DR

This paper demonstrates a spin-1 Dicke model using ultracold rubidium atoms in a cavity, revealing non-equilibrium phase transitions including super-radiant and oscillatory phases, and maps their phase boundaries.

Contribution

First realization of a spin-1 Dicke model with ultracold atoms in a cavity, exploring non-equilibrium phases under imbalanced driving conditions.

Findings

Observation of super-radiant and oscillatory phases

Mapping phase boundaries between normal, super-radiant, and oscillatory states

Experimental results agree with theoretical predictions

Abstract

We realize a spin-1 Dicke model using magnetic sub-levels of the lowest F=1 hyperfine level of $^{87}$Rb atoms confined to a high finesse cavity. We study this system under conditions of imbalanced driving, which is predicted to have a rich phase diagram of nonequilibrium phases and phase transitions. We observe both super-radiant and oscillatory phases from the cavity output spectra as predicted by theory. Exploring the system over a wide range of parameters, we obtain the boundaries between the normal, super-radiant and the oscillatory phases, and compare with a theoretical model.