Non-equilibrium phase transition in a spin-1 Dicke model
  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. 
Zhang Zhiqiang, Chern Hui Lee, Ravi Kumar, K. J. Arnold, Stuart J.   Masson, A. S. Parkins and M. D. Barrett
quant-ph