Dynamics and Protecting of Entanglement in Two-Level Systems Interacting   with a Dissipative Cavity: The Gardiner-Collett Approach
  In this paper, we study the exact entanglement dynamics of two two-level atoms in a dissipative cavity. We use the Gardiner-Collett Hamiltonian to model the dissipative cavity, in which, we assume that the two atoms resonantly interact with the cavity field and the cavity field itself interacts with the surrounding medium. Then, with the help of the Fano's technique, we show that, this system can be regarded as two atoms interacting with a heat bath. In such a case, we find that, there exists a decoherence-free state that does not evolve in time. At this time, there exists a so-called super-radiant state which decays in time due to dissipation. At last, we use the quantum Zeno effect to preserve the entanglement which already has been stored in the system. 
Alireza Nourmandipour and M.K. Tavassoly
quant-ph