Quantum coherence in ultrastrong optomechanics
  Ultrastrong light-matter interaction in an optomechanical system can result in nonlinear optical effects such as photon blockade. The system-bath couplings in such systems play an essential role in observing these effects. Here we study the quantum coherence of an optomechanical system with a dressed-state master equation approach. Our master equation includes photon-number-dependent terms that induce dephasing in this system. Cavity dephasing, second-order photon correlation, and two-cavity entanglement are studied with the dressed-state master equation. 
D. Hu, S.-Y. Huang, J.-Q. Liao, L. Tian, and H.-S. Goan
quant-ph cond-mat.mes-hall