量子通信网络及其路径优化中的若干问题

Nowadays, much attention has been paid on the quantum communitation technology in both its theoretical and experimental aspects. There is an increasing concern on its architecture, protocols and algorithms.In this project, in the context of of strengthing the information processing capabilities of the cloud servers and weakening the requriments for the preformance of client nodes, we will address several key issues on distributed quantum communication networks. First, combining with various channels via multi relay nodes, we will present a scheme for remote state preparation of general high dimensional quantum states and its circuit design. Second, with the high dimensional non-maximally entangled state or mixed stats as quantum channels linked between multi relay nodes, we will propose an optimized and general scheme for remote implemention of local quantum operations and local implementation of nonlocal quantum operations. Third, in the case of clients equipped with limited technology linked by multi relay nodes and cloud servers, we will explore how to utilize the cloud servers help both clients communicate with each other. Last, when selecting the best relay paths between the clients, with several key indicators such as routing hops, ground-air channel conditions, entanglement resource and channel setup time as the constraints adopted, we will present a multi-objective optimization algorithm in the quantum communication network. Our project aims to provide new insights into the quantum communication network which leads to obtain the information transform rule and the optimized scheme for quantum remote operation under consideration of network. Finally several key algorithms and protocols on quantum communication network are established in a clear, flexible and economic manner.

当前，量子通信技术理论和实验的发展日新月异，对量子通信网络的架构、协议及算法的研究日益成为关注热点。在加强量子通信网络中云计算中心服务器性能和弱化对客户端本身技术能力需求的前提下，本项目拟对量子通信网络中的重要协议进行研究，通过优化组合不同形式的量子信道，给出经由多中继完成任意能级量子态的远程制备方法及其量子线路的设计；考察一般能级的量子体系，利用非最大纠缠纯态信道或者混态信道，经由多中继,完成局域量子操作的最优远程实现和非局域量子操作的最优局域实现；在选择客户端之间进行通信的中继路径时，采用路由跳数、星地信道状况、纠缠资源和信道建立时间等实际指标作为多维约束参数，给出基于量子通信网络的多目标路径优化算法。本项目的研究成果将为量子通信网络提供新的分析和综合思路,挖掘网络环境下信息转移规律以及最优量子远程操作的策略，最终形成工程上易于理解、操作和应用的量子通信网络若干重要算法和协议。

随着量子通信技术的发展，早期的点对点之间通信行为已逐步开始向多方参与的量子网络化方向过渡，因此迫切需要新的理论和方法来支撑量子通信网络的规划和设计。本项目主要研究了量子通信网络中的资源消耗和信息传送过程中安全性问题。主要研究内容包括：1）任意多能级量子态共享方法，该方法实现了基于最大纠缠信道以及一般纠缠信道的高维量子态远距离共享，且给出了具体的操作线路，2）多方参与联合控制多个独立信息的传送方法，该方法达到资源配置的最优；3)超快宽带/窄带脉冲激光与类似于铷原子的多能级体系相互作用时的量子路径控制策略,完成了量子系统相干路径的信息提取；4）量子通信网络中的冗余保护路径的设置和工作方法方案，该方案可以防止未知量子信息在传输过程中受到破坏而不能恢复，从而极大提高量子通信过程中信息传输的安全性、稳定性和可靠性；5) 联合制备任意多比特W态的优化方法。该方法实现远程量子态制备过程中降低量子比特资源消耗和经典通信成本的最优，且可以有效地推广到任意多比特态远程制备过程中。