Dynamics of atom-field entanglement in a bimodal cavity

In this paper we investigate some aspects of the dynamics and entanglement of bipartite quantum system (atom-quantized field), coupled to a third “external” subsystem (quantized field). We make use of the Raman coupled model; a three-level atom in a lambda configuration interacting with two modes of the quantized cavity field. We consider the far off resonance limit, which allows the derivation of an effective Hamiltonian of a two-level atom coupled to the fields. We also make a comparison with the situation in which one of the modes is treated classically rather than prepared in a quantum field (coherent state).