Multiparty Remote Preparation Of Arbitrary Two-and Three-qubit States

Secure transmission of a quantum state is one of the crucial tasks in the field of quantum communication. Remote state preparation (RSP) provides a novel way for the trans-mission of a known state by utilizing priorly shared entanglement and some classical communication. So far, RSP has received much attention both theoretically and experi-mentally due to its important application in quantum communication. The dissertation mainly focuses on the research of multiparty RSP protocols. The content of this disser-tation relates to the controlled remote state preparation (CRSP) of arbitrary two- and three-qubit states, joint remote state preparation (JRSP) of arbitrary two-qubit state.The principal contributions of the work presented in the paper are briefly summarized as follows:1.Two controlled remote state preparation protocols via the Brown state as the entangled channel are proposed. One prepares an arbitrary two-qubit state, and the other prepares an arbitrary three-qubit state. It is worth mentioning that Hurwitz matrix equation plays a key role in the construction of measurement basis. Comparing with the previous protocols, the novel schemes have no restriction on the coefficients of the prepared state while keeping the same success probability 50%. It means that the application of the proposed schemes are more extensive in practice. We also discuss the special complex coefficient ensembles with unit success probability.Furthermore, by constructing suitable measurement bases, we propose two deter-ministic RSP schemes using the Brown state. The proposed schemes can be extended to CRSP with unit success probabilities. At variance with the existing CRSP schemes via the Brown state, the derived schemes have no restriction on the coefficients, while the success probabilities can reach 100%.2.The joint remote preparation of an arbitrary two-qubit state with a passive receiv-er are investigated. By constructing a new set of measurement basis, we devise a JRSP protocol with two senders via EPR pairs as the entangled channel. Comparing with the previous protocol, multi-particle project measurement is simplified and the cost of clas-sical information is reduced. Moreover, JRSP with more than two senders is considered.When the number of senders increases, the advantage is more evident. It means that the proposed schemes are more efficient in practice.