Theoretic Study On Remote Preparation Of A Two-Particle Entangled State

During the rapid development of the information science, it is inevitable to suffer from its developing bottle-neck. Under this historical background, the quantum information science based on quantum theory has emerged, and it has attracted a wide attention in virtue of its unique character. Quantum information science is a new interdisciplinary subject, which is a combination of quantum mechanics and information science. Quantum communication is one of the most important branches of the quantum information. It mainly contains quantum teleportation, quantum dense coding, quantum key distribution and remote state preparation, etc. As an interesting field in quantum communication, remote state preparation has been studied both in theory and in experiment since its inception, and some valuable results have been obtained.This thesis focuses on the remote preparation of a general bipartite entangled state. Firstly, a brief introduction of the background about quantum information is presented, and the developments on remote state preparation are set forth. Two schemes for remote preparation of a general two-particle entangled state then are proposed, and the corresponding success probabilities are discussed as well. In the first scheme, a bipartite entangled state and a tripartite entangled W state are applied as the quantum channel to realize the remote state preparation by means of the method of unitary-collapse, and the classical communication cost required in the scheme is calculated in detail. The result shows that the classical communication cost is relative not only to the shared quantum channel but also to the initial state to be teleported. In the second scheme, in order to remotely prepare a bipartite entangled state, a POVM measurement is performed on an ancillary particle, and two tripartite entangled W states are used as the quantum channel. In the present two schemes, the initial state can be transmitted from a sender to either one of the two receivers, and the total success probability of RSP is generally different for each receiver. In addition, both schemes can be generated directly to the case of N receivers.The research results are useful to make a profound research on quantum communication process and the trade-off between the classical communication cost and the entanglement required in remote state preparation, and are significant to investigating the application of remote state preparation in a sense.