Entanglement degree of a three-level atom interacting with pair-coherent states with a nonlinear medium

It has been become known that a quantum entangled state plays important rol e in fields of quantum information theory, such as quantum teleportation an d quantum computation. Research on quantifying entangled states has been ca rried out using several measures. In this paper, we will adopt this method using quantum mutual entropy to measure the degree of entanglement (DE) in the time development of a three-level atom interacting with two-mode pair-c oherent states in a Kerr-like medium. The exact results are employed to per form a careful investigation of the temporal evolution of the entropy. A fa ctorization of the initial density operator is assumed, with the privileged field mode being in pair-coherent states. We invoke the mathematical notio n of maximum variation of a function to construct a measure for entropy flu ctuations. It is shown that when the individual modes of the field are far detuned from the intermediate atomic level; the dynamical Stark shift induc ed by the Kerr-like medium. The results show that, the Kerr effect yields t he superstructure of atomic Rabi oscillation. A possible experimental test of a new effect is proposed. The general conclusions reached are illustrate d by numerical results.