Theoretical Study On Teleportation,State Sharing And Operation Sharing

Employing the quantum and classical channels constructed in advance,quantum teleportation can accurately transmit an unknown quantum state to a remote qubit without sending any physical carrier.Due to its magical property that no classical process can be realized,quantum teleportation and related technologies play an important role in resource allocation and remote control in quantum communication and remote quantum computing.Based on the quantum teleportation technology,in this paper we want to study how to use multi-qubit entangled states to realize the teleportation and sharing for quantum states and quantum operations.The specific research contents are as follows:1.Research on quantum operation sharing(QOS)Using 5-qubit GE state,cluster state and 6-qubit AME state respectively,we design three tripartite quantum operation sharing(QOS)schemes.They both have the characteristics of arbitrariness and certainty.Compared with the similar schemes reported in the existing literature,the classical and quantum resource consumption of our schemes are fewer,the intrinsic efficiencies of the schemes are higher,and the necessary quantum operations are relatively less.In addition,we also give the general entanglement structures of quantum-channel states which are suitable for QOS tasks,and give three general methods to obtain multi-qubit entangled states with these special entanglement structures.2.Research on bidirectional quantum operation teleportation(BQOT)Combining the two ideals of quantum operation teleportation and bidirectional quantum communication,Si-Qi Zhou et al.creatively put forward the concept of bidirectional quantum operation teleportation.However,the specific schemes they subsequently proposed had some serious problems.Employing 8-qubit cluster states as quantum channel,we propose a real scheme for bidirectional quantum operation teleportation.In the present scheme,two remote users can simultaneously perform their single-qubit unitary operations on each other's an arbitrary unknown single-qubit target quantum state,respectively.Besides,the operations to be teleported are arbitrary,the chances of successful sharing are deterministic,and it can be applied in the future quantum network to achieve bidirectional remote control.3.Research on bidirectional controlled quantum teleportation(BCQST)Based on the 5-qubit Brown state,we propose a scheme for bidirectional controlled quantum teleportation.In this scheme,once the third-party supervisor's consent and help are obtained,two remote users can teleport an arbitrary and unknown single-qubit unknown target quantum state to each other.Compared with Chen Yan's scheme(Int.J.Theor.Phys.,2014,53:1454)which uses the same quantum-channel state to implement BCQST tasks,our scheme uses less one 2-qubit unitary operation and avoids two nonlocal joint operations.This reduces the difficulty and intense of the necessary quantum-operations in our scheme and greatly enhances its working flexibility.In addition,analysis and calculation show that our scheme consumes less classical resources and has higher intrinsic efficiency than Chen Yan's original scheme.4.Research on quantum state sharing(QSTS)with mixed statesIn quantum networks,multi-qubit entangled states might evolve to mixing ones due to some certain reasons such as qubit confusion and decoherence.As a pioneering study,we discuss the possibility of using mixed entangled states as quantum channels to process quantum information,and propose an effective scheme to implement tripartite qsts tasks by using a specific mixed state(two qubits in the genuine entangled pure state of 6 qubits are derived from confusion).We have made a detailed analysis on many aspects of the scheme,including the certainty of the scheme implementation,the symmetry of the sharer,the security of the scheme,the essential role of the quantum channel and the feasibility of the current experiment.