The Properties Of Entanglement Of The Optical Field Interacting With The Atom Under Phase Decoherece Condition In The Multiphoton Process

Entanglement is basic features that distinguish the quantum World from the classical world. Quantum entanglement is recognized as a major resource in the field of quantum teleportation and communication. People have been looking forward to resolve the important issue of practical significance which exploring how to get a better coherence of entangled states under the phenomenon of phase decoherence. This paper studies the optical field and the two two-level atoms interacting quantum entanglement properties. The main content of this thesis are as follows:(1) Briefly discussed the basic theory of quantum entanglement and non-classical effects of light field and introduced the Concept of the phase decoherence,the binomial field and so on.(2) The influences of the phase decoherence coefficient on the properties of the entanglement evolution between two atoms have been discussed. The results show that the phase decoherence doesn't destroy coherence completely but attenuates oscillated amplitude of the entanglement degree between two entangled atoms, then the entanglement degree will quickly become a constant.(3) Discussing the influences of the dipole-dipole coupling intensity on the properties of the entanglement evolution between two atoms by means of the quantum theory. The results show that the bigger the dipole interaction between two atoms, the better the coherences between two atoms. Thus the larger value of entanglement degree between two entangled atoms could be obtained and the state in which two entangled atoms are is more stable in a relatively short time by selecting the appropriate phase decoherence factor.(4) The influences of the number of the transitional photons on the properties of the entanglement evolution between two atoms have been discussed. The results show that the periods of the entanglement evolution and the intensity of entanglement will be changed and disentanglement phenomenon will be avoided with the changing of the number of the transitional photons by selecting the appropriate parameters.(5) By means of the quantum theory and the method of the negative eigenvalues of the partial transposition, the properties of entanglement evolution in the system of two two-level atoms coupled to a light field in the binomial state for radiation field are investigated in the presence of phase decoherence in the multiphoton Tavis-Cumming Model. The influences of the maximum number of photons, the coefficient of binomial state for radiation field, the phase decoherence coefficient and the number of the transitional photons on the entanglement degree between two atoms have been discussed.