Degree of entanglement for anisotropic coupled oscillators interacting with a single atom

In this paper we introduce a new Hamiltonian which represents the interaction between a two-level atom and two modes of an electromagnetic field injected simultaneously within a cavity. Field–field interaction of the parametric converter type is taken into consideration. Under certain conditions the solution to the Schrödinger equation is obtained exactly. By using this solution we discuss numerically the degree of entanglement through the entropy of the field, for chosen values of the detuning and coupling parameters.