Dynamic Behavior of Entanglement Between Two Spatially Separated Atoms in Two Dissipative and Driven Cavity Fields

We consider two two-level atoms, interacting with two independent dissipative cavities, each of which is driven by an external source. The two cavity fields are both initially prepared in the coherent states, and the two two-level atoms are initially prepared in the singlet state |� i = (|egi | gei)/ p 2. We investigate the influence of the damping constant �, the intensity of the external sources F, and the relative difference of the atomic couplings r on the entanglement between the two atoms. In the dispersive approximation, we find that the entanglement between the two atoms decreases with the time evolution, and the decreasing rate of entanglement depends on the values of F/�, �/!, and r. For the given small values of F/� and �/!, on the one hand, the increasing of r favors entanglement decreasing of the atomic system, on the other hand, when r ! 1 the entanglement decreasing becomes slower. With the increasing of the value of �/!, the influence of r on the decreasing rate of entanglement becomes smaller, and gradually disappears for the big value of �/!.