Nonequilibrium Quantum Phase Transitions in the Dicke Model
  We establish a set of nonequilibrium quantum phase transitions in the Dicke model by considering a monochromatic nonadiabatic modulation of the atom-field coupling. For weak driving the system exhibits a set of sidebands which allow the circumvention of the no-go theorem which otherwise forbids the occurence of superradiant phase transitions. At strong driving we show that the system exhibits a rich multistable structure and exhibits both first- and second-order nonequilibrium quantum phase transitions. 
V. M. Bastidas, C. Emary, B. Regler, and T. Brandes
quant-ph cond-mat.quant-gas