SOME MODELS IN THE QUANTUM OPTICS

Abstract

The quantum information with emphasis on the entropy and entangle­ ment, is reviewed. After an introduction to the basic concepts of the tra­ ditional quantum computer and methodology, the main phenomena and ex­ perimental observation are summarized. This is followed by the discussion of the main ideas underlying various approaches, especially as they pertain to the single-atom problem. We consider the quantum field entropy and the Pancharatnam phase of the field interacting with a two-level atom with an additional Kerr-like medium for one-mode and two-modes. The general solution ofSchrodinger equation for the interaction between a two-level atom and one mode of the electro magnetic field, when the cav­ ity is filled with a nonlinear Kerr-medium has been given. The quantum field entropy and Pancharatnam phase are calculated and investigated. For a general class of two-mode of the electro magnetic field, simple

analytic expressions are derived for the evolution of the quantum field en­ tropy in the bimodal field interacting with an effective two-level atom via the Raman transition, with an additional Kerr-like medium. The effect of a Kerr-like medium on the entropy is analyzed. It is shown that the addi­ tion of the Kerr-like medium has an important effect on the properties of the entropy and entanglement. The results show that, the effect of the Kerr medium changes the quasiperiodic evolution of the field entropy and entan­ glement between the atom and the field.