Quantum Entanglement And Entanglement Swapping In The System Of Atoms Interacting With Cavity-field

Quantum informatics is a new discipline which is yielded by the combination of physics and information science and which is established recently. Quantum informatics includes such fields as manipulation and preparation of quantum states, quantum teleportation, quantum communication and light-quanta communication, quantum coding and quantum-intensive coding, quantum cloning and cloning of quantum probability, quantum algorithms and quantum computing, quantum control and quantum recognition, quantum measurement and non-destructive quantum measurement, quantum entanglement and entangled exchange, and so on. Here, quantum entanglement and entangled exchange is one of the key research subject in the regime of recent international quantum informatics, it has very important academic value and broadening application prospect to study this subject further.In this thesis, the problems of quantum entanglement and entangle exchange in the system of atoms interacting with cavity-field are studied deeply by utilizing the full quantum theory.(1) Both the three-particles GHZ state and W state are analysized in detail, the scheme for preparing a special three-particles entanglement state is given, and the properties of quantum entanglement of the state mentioned above are further disscused.(2) It is studied that the problem of entanglement control and entanglement exchangle in the process of entanglement two-level atoms which stayed in two-particles EPR state interacting with a single-mode coherent state light-field.(3) It is studied that the problem of entanglement control and entanglement exchange in the process of the three entangled two-level atoms stayed in GHZ sate and interacting with a single-mode coherent state light-field.(4) The time evolution property of second-order coherence of light-field and the time evolution characteristic of quantum entropy of light-field are studied in detail, that is in the process of the three entangled two-level atoms stayed in W state and interacting with a single-mode light-field stayed in binomial-state.These research results have very important theoretical guidance for further realizing quantum state control and its preparation in the experiment, for realizing the control and exchange of quantum entangled information in common use, and so forth.