Entropy Evolution Of Entangled Atoms Interacting With Light Field

Entanglement is one of the most striking features of quantum mechanics, and plays key pole in quantum information science. Entanglement states are very important topics in quantum optics, which attract huge interest nowadays. It is important that optical fields interact with atoms in quantum optics. In 1963,Jaynes and Cummings described a physical model of two-level atom and one mode optical field. Physicists do many studies and expansions.In this paper, we study the interaction of entangled atoms with the light field by using the J-C Model. When one atom is exposed to the field, entanglement properties of two entangled atoms interacting with light field under intensity-dependent coupling have been studied. Also, by manipulating the atom outside the field, we study the entanglement between the field and the atom inside the field. It is found that the intensity-dependent coupling makes the atom-atom and atom-field entanglements change periodically and the maximum entanglement is kept during the evolution. Without the intensity coupling, the maximum atom-atom entanglement is not kept. Without the intensity-dependent coupling, the entanglement doesn't follow regular rule except the case that the photon number is zero. By manipulating the atom outside the field,we can say that entropy evolution of the atom inside the field interacting with light field appears entanglement and disentanglement.