Research On Remote State Preparation Based On Combined Channels

Quantum communication is a new interdisciplinary discipline developed in the last two decades,which is a new research field combining quantum theory and information theory.In quantum communication,information is transmitted through quantum entanglement effects.In this thesis,common quantum entangled states are combined and several schemes for remote quantum states preparation based on combined channels are investigated.First,this thesis explores a joint remote quantum state preparation scheme based on single-relay node and the maximally Greenberg-Horne-Zeilinger(GHZ)-Bell entangled channel.Further,a joint remote quantum state preparation method through single-relay node and the non-maximally entangled GHZ-Bell channel is also investigated.In the two schemes,the local nodes share the maximally/non-maximally entangled GHZ channels,and the relay node shares the Bell pairs with the local node and the remote receiver node.Through entanglement swapping,the local sender nodes can remotely prepare arbitrary single-qubit states for the remote receiver node.This thesis utilizes a non-maximally entangled channel to reduce the quantum channel requirements of the scheme.Second,this thesis extends the single-relay node scheme to the multi-relay nodes scheme,and proposes a long-distance remote state preparation of arbitrary single-qubit states through multi-relay nodes and the combined GHZ-Bell channel.The local nodes share the maximally entangled GHZ channel,and each local node has a Bell chain extending to the remote end.This scheme can overcome the limitation of distance in remote quantum state preparation by means of the GHZ channel of the local nodes and the Bell chain between the relay nodes.Through the entanglement swapping,the quantum entanglement channel required by the scheme is finally formed by the remote node.In this way,this scheme can realize remote state preparation of arbitrary single-qubit states.Finally,by utilizing a nine-qubit Cluster-GHZ state without introducing auxiliary qubits,this thesis proposes a scheme for remote state preparation of arbitrary three-qubit states.Furthermore,this thesis proceeds to investigate the effects of different quantum noises(e.g.,amplitude-damping,phase-damping,bit-flip and phase-flip noises)on the systems.It is found that the fidelity of the phase-flip noisy channel drops the fastest through the four types of noisy channels,while the fidelity is found to always maintain at 1 in bit-flip noisy channel.