QUANTUM ENTROPY FOR A NON-LINEAR INTERACTION SYSTEMS.

Abstract

In this thesis, we examine some quantum models to study a quantum entropy for a non-linear interaction systems. In this regard, we discuss a system of a three-level atom interacting non-linearly with a single-mode of electromagnetic cavity quantized field. Under the timedependent coupling parameter and decay of the field in the presence of Kerr-like medium and Stark shift. We investigate this system by proposing convenient non-Hermition Hamiltonian. The wave function, the probability amplitude and expression of the reduced density operator of the atom are obtained when the atom is initially prepared in its uppermost state and the field is initially prepared in coherent state . The entanglement via concurrence, atomic inversion and Shannon entropy are studied under the effects of time-variation coupling parameter, damping of the field, Stark shift contribution and Kerr-like nonlinearity.