Entanglement in multi-photon Tavis - Cummings model induced by a thermal noise

In this paper we have investigated the dynamics of entanglement of two natural or artificial two-level atoms interacting through multiphoton transitions with a thermal field of an lossless microwave cavity. On the basis of the exact solution of the model under consideration, the atom-atom entanglement parameter for various initial separable and entangled states of atoms are found. It is shown that the interaction of atoms with the thermal field of the cavity by means of multiphoton transitions can induce entanglement for all states except for the one in which both atoms are excited. It is also established that for the initial separable states of atoms the maximum degree of entanglement increases with the multiplicity of atomic transitions.