atom-photon thermal entanglement in a single-mode cavity

In this paper, we consider the jaynes-cummings model that describes the interaction of atwo-level atom with a single-mode cavity. we assume that the cavity is in thermal equilibrium with aheat reservoir at a temperature t. we obtain the thermal state of the system and investigate theentanglement as a function of t. to this aim we use the concurrence, as a measure of entanglement.the effect of detuning between the radiation field and atomic transition and atom-field coupling.constant, on the degree of thermal entanglement between the atom and photon is investigated