| Quantum information science is mainly concerned with quantum mechanics and information technology,etc.The scope covers many professional fields such as physics,mathematics,computer technology,and communication.With the joint development of various theories and experiments such as quantum key distribution,quantum teleportation,remote state preparation,and quantum secure communication,researchers are competing to improve the security of communication as well as transmission efficiency by breaking existing physical constraints and using new techniques.Multi-qubit entangled states with different degrees of entanglement and forms of entanglement are of great significance in promoting the development of quantum information transmission schemes with various novel modes.Remote state preparation is based on the extension of quantum teleportation,which has greater advantages in terms of entanglement resource consumption,transmission efficiency,and information security.Based on the study of multi-qubit entangled quantum states and remote state preparation,this thesis proposes quantum information transmission schemes for two specific communication scenarios,taking into account the synchronization problem of multi-user cyclic transmission of incremental information and the efficiency problem of hierarchical reception of information.The specific research results of the two schemes and their innovations are presented below.1.Aiming at the specific communication application scenario of cyclically transmitting information with an increasing number of qubit(quantum information bits),a scheme of multiparty controlled cyclic asymmetric quantum state remote preparation is proposed in this thesis.Taking the four-party controlled cyclic asymmetric remote state preparation scheme as an example,the implementation steps of the scheme are described in detail,and the feasibility of the scheme is confirmed by quantum simulations in the IBM Q Experience platform.Furthermore,considering the mutual coupling between the open quantum system and the environment,the influences including the measurement basis coefficients and the decoherence rate of four different noises channel(depolarization,amplitude damping,phase decay,and bit-phase flip)on the fidelity of the output quantum state are discussed.Compared with other modes of remote state preparation,the scheme of controlled cyclic asymmetric remote state preparation realizes the simultaneous transmission of the incremental qubit information of the participants,improves the security and transmission efficiency of information transmission,and reduces the overhead of quantum entangled state resource.2.In the existing hierarchical quantum information transfer scheme,the level division between receivers is limited and complicated to implement.In this thesis,an information transmission scheme for quantum state remote preparation of any level is proposed,and the high-level receiver only needs the sender’s measurement results to reconstruct the quantum state,and the lower-level receiver can reconstruct the information with only the help of the sender and the receivers whose level are higher.Generalized quantum channel expressions for communication schemes extended to any 9)levels with any 8)receivers at any level are summarized.Based on the quantum computer of the quantum origin cloud platform,the construction of quantum circuit simulation realizes the simplest three-party hierarchical remote state preparation.Finally,the quantum state tomography is performed on the output quantum state of the quantum circuit simulation,and the analysis shows that the efficiency and performance of the high-level receiver and the low-level receiver in the scheme are higher than in other schemes.The hierarchical quantum state remote preparation scheme utilizes the quantum properties of the combination of cluster states and GHZ states to achieve hierarchical reception of quantum information,which improves the hierarchical nature and security in quantum information transmission. |
