Cavity-loss induced plateau in coupled cavity QED array

Abstract: Nonequilibrium steady states are investigated in a coupled cavity QED array system which is pumped by a thermal bath and dissipated through cavity loss. In the coherent (non-zero photon amplitude) phase, plateau regions appear, where the steady states become unchanged against the variation of the chemical potential of the thermal bath. The cavity loss plays a crucial role for the plateaus: the plateaus appear only if the cavity loss exists, and the photon leakage current, which is induced by the loss, is essential to the mechanism of the plateaus.