基于量子反馈控制的分布式稳态纠缠设计

In current stage of quantum computing, efforts are devoted to fighting against decoherence and developing the logical qubit with longer coherent time. Quantum feedback control has emerged as a promising method to improve the coherence time of many body system. Also remote steady entanglement is the fundamental element of quantum network. The project propose to construct the remote steady entangled states via photon interferometry measurement and quantum feedback control, aiming to improve the rubustness of the entanglement of many body system. The influences of detector efficiencies, local decay channels and parameter fluctuations will also be analyzed. On the other hand, the project will explore the general principle in the transition design of the system, and try to establish theorems about the relation between steady state and decay operators. The project will also study the coupling model of distant solid system and feedback schemes in these systems. The accomplishment of the project will facilitate the progress in quantum measurement and control theory, and has a great significance in the achievement of fault-tolerant quantum computing and quantum network.

抵御退相干，发展高稳定性逻辑比特，是时下量子计算发展阶段正在解决的问题。量子反馈控制是提高多体系统量子相干性的关键性技术，分布式稳态纠缠也是实现量子网络的基础元素。本项目拟通过光子干涉测量的设计和反馈方式的设计构建多种各方分离的稳态纠缠，提高多体纠缠对退相干的抵御能力，并分析探测器效率、局域退相干途径、参数波动等因素对方案的影响。并且在此过程中，探索系统跃迁设计的一般性原则，发掘主方程耗散算符形式与系统稳态的关系。本项目还将研究远距离固态系统之间的耦合连接，以及在这种系统中构建稳态纠缠的反馈控制方案。本项目的顺利完成将进一步完善量子测量和控制理论，对容错量子计算和量子网络的实现具有重要意义。

项目研究了腔QED中纠缠的产生和演化过程。项目研究了电路QED中基于量子拉比模型的多比特纠缠的产生，讨论了量子拉比模型中退相干对比特纠缠的影响，发现在这种模型中多比特纠缠可以很高的保真度实现。项目研究了量子拉比模型中两比特逻辑门的构建，分析发现构建过程对参数波动有较好的抵御性。项目研究了超导比特与NV色心复合系统中纠缠的演化，发现一些参数对纠缠演化的调控作用。项目的研究对电路QED和复合系统中纠缠的构建和调控有一定的基础意义。