Properties, Preparation And Application Of Quantum Entanglement Pure States

Quantum entanglement is a potential resource for quantum communication and quantum information processing, and can be used to test basis problems in quantum mechanics. It is significant to study the quantum entanglement quantitatively and qualitatively and its application in the field of quantum information. In this thesis, we focus our research in preparation of multipartite entangled pure states, entanglement configurations and entanglement properties in terms of local measurements and disposal of particles. Meanwhile, we also point out their possible applications. The main results of this thesis are as follows:1. We have studied the entanglement properties of some tripartite entangled pure states. The results show that the entanglement properties of the same class under SLOCC may be different except for the equivalent states under LU. We have proposed a scheme to prepare a set of tripartite entangled states and studied its entangled properties. We find that in the set of tripartite entangled state except for GHZ state, the peculiar tripartite entangled states have three-way entangled as GHZ state and two-way entangled as W state simultaneously. Also, the remaining reduced density matricesρ_ij can retain entanglement or disentanglement independently, which can be chosen freely according to our requirement, and the relative entanglement strength of any pair of particles can be arbitrarily adjusted.2. We have proposed a scheme to prepare a certain kind of N-atom entangled state that allows us to construct some possible type of"entanglement molecules"via cavity QED. We have investigated the possible configurations and the relative entanglement strengths of entangled chains of entanglement molecules in detail; the properties of"entanglement molecules"are studied with respects to bipartite entanglement and local measurement, and compared with other kinds of multipartite entangled states such as the | GHZ>, | W_N>, |φ_N> andρ_I states. The results show that the entanglement persistency has the...