The Entanglement Sudden Death And Anabiosis In The System With Field-atom Interaction

The quantum entanglement is the key physical resource of quantum computation and quantum information processing.The quantum system is inevitably influenced by the surrounding environment under the usual conditions.The interaction between environment and quantum system can cause decoherence and lead to entanglement decay and death.In recent years,the phenomenon of the entanglement sudden death and anabiosis has been payed more and more attention.The entanglement sudden death and anabiosis in the system with field-atom interaction is studied by using the quantum entanglement theories.Some significant new results are obtained as follows:In chapter 1,the basic conceptions of quantum entanglement are presented. Firstly,the presentation and definition of quantum entangled states,EPR paradox, and Bell inequality,as well as their properties,are given.Secondly,the measurement of the degree of quantum entanglement and manipulation of quantum entanglement are introduced.Finally,the current situation of the entanglement sudden death and anabiosis is introduced.In chapter 2,the entanglement:sudden death and anabiosis between two moving atoms is investigated by concurrence.It is shown that atomic motion leads to the entanglement periodic death and anabiosis between two moving atoms;As the parameter of the mode field increases,however,the period of the entanglement sudden death and anabiosis shorten.The time of the entanglement sudden death and the amplitude of the entanglement sudden anabiosis between two moving atoms depend on the initial states of two moving atoms. In chapter 3,the entanglement dynamics between an isolated atom and a moving atom in the cavity is studied by negativity.The entanglement of isolated atommoving atom and atom-cavity are concretely reviewed.The results show that,firstly, the time of the entanglement sudden death is not dependent on the initial states of the system(except for the direct product states);secondly,the isolated atom can also periodically entangle with cavity which stems from the fact that the entanglement between two atoms may transfer into the entanglement between the isolated and the cavity.