NONLINEAR EFFECTS ON THE ENTANGLEMENT BETWEEN QUANTIZED ELECTROMAGNETIC FIELDS AND 3-LEVEL ATOMS.

In this paper, we study the entanglement dynamics, its measure, and mean photon number of the field in the interaction between a quantized electromagnetic field and a 3-level atom surrounded by a nonlinear Kerr-like medium. Using the density matrix approach, we have calculated the time evolution of the entanglement and its magnitude at an arbitrary time, for different nonlinear coupling constant. Moreover, to show the effects of nonlinearity on the atom-field interaction and its relation with the entanglement the mean photon number of the field is also presented as a function of nonlinear coupling strength, χ. The results show that, envelope of entanglement fluctuation, their duration and amplitude strongly depend on the nonlinear coupling strength. Since the entanglement decreases with increasing nonlinearity, the mean number of photons reaches a constant value as a result of absorption increment by the surrounding medium. [ABSTRACT FROM AUTHOR]