First-order super-radiant phase transitions in a multi-qubit--cavity   system
  We predict the existence of novel first-order phase transitions in a general class of multi-qubit-cavity systems. Apart from atomic systems, the associated super-radiant phase transition should be observable in a variety of solid-state experimental systems, including the technologically important case of interacting quantum dots coupled to an optical cavity mode. 
Chiu Fan Lee, Neil F. Johnson