Nonlinear Medium, The Interaction Of Light With Matter Quantum Entanglement Properties

The quantum entanglement ,as one of the most prominent feature of quantum mechanics, plays an important role in the Quantum Informatics which includes quantum information theory, quantum communication, quantum computation and so on, especially in information processing. For this reason, it becomes one of the most prominent Research Orientation. Generating entangled state is a key part of the quantum entanglement. The Jaynes-Cummings model has been widely studied because it can be precisely resolved.On the base of Jaynes-Cummings model, we studied the quantum entanglement of the binomial field interacting with a cascade three-level atom and the two-mode SU(1,1) coherent states interacting with three-level atoms ,which include a V-type three-level atom, aΛ-type three-level atom and aΞ-type three-level atom in a Kerr-like medium. The result showed the Kerr coefficient and other parameters can affect the quantum entanglement of the system .Employ the Jaynes-Cummings model, the state vector of the system, the binomial field interacting with a cascade three-level atom, has been derived. On the base of this, the Von Neumann entropy can be obtained. Then the effect of Kerr coefficient on the quantum entanglement has got by numerical calculation. The results indicate when the atom initially in excited states ,the field entropy increases with the increasing of Kerr coefficient, the quantum entanglement is improved too. However, the field entropy reduces when the parameter over a certain value and the period of field entropy becomes longer .When the atom initially in levels'superposition states, the field entropy reduces with the effect of Kerr effect and the entanglement between atom and optical field becomes lower. The field entropy could be improved unless the parameter over a certain value .Then the law is the same as the case of the atom initially in excited states with the increasing of Kerr coefficient.The effect of Kerr coefficient, the differentials of the photon number between the modes and the initial field intensity on the quantum entanglement of the system, the two-mode SU(1,1) coherent states interacting with three-level atoms, has been studied. The study shows all of the parameters can affect the quantum entanglement. The law is the same as the system of the binomial field interacting with a cascade three-level atom, before the parameter of Kerr reaches a certain value the quantum entanglement increases rapidly with the increasing of it. However, the quantum entanglement is reduced when the parameter over the certain value .