Entanglement induced by the two-mode thermal noise

The entanglement between two identical two-level atoms interacting with a two-mode thermal field through a nondegenerate two-photon process is investigated. It is shown that two atoms can be entangled through a nonlinear nondegenerate two-photon interaction with two-mode thermal field. On the contrary, for the two-atom Raman coupled model the entanglement is impossible.