Entanglement evolution of a two-qubit system with decay beyond   rotating-wave approximation
  Two noninteracting atoms, initially entangled in Bell states, are coupled to a one-mode cavity. Based on the reduced non-perturbative quantum master equation, the entanglement evolution of the two atoms with decay is investigated beyond rotating-wave approximation. It is shown that the counter-rotating wave terms have great influence on the disentanglement behavior. The phenomenon of entanglement sudden death and entanglement sudden birth will occur. 
Qing Yang, Ming Yang, Da-Chuang Li, Zhuo-Liang Cao