实际量子信息系统中量子关联态动力学调控研究

The local decoherence induced by the external environment would destroy the initial quantum correlations of the realistic quantum information system, so the breaking of quantum correlation states limits their application in the practical quantum information process. The issue of how to avoid or control quantum correlation decay in a realistic physical system is very important. In this project, firstly，by studying entanglement dynamics of quantum system under the different environmental and exactly solvable models, we want to find the physical parameter areas in which entanglement sudden death can be inhibited or the initial entanglement would be preserved. And then we would like to acquire a physical system with the optimal parameters in the practial quantum information process. Then we explore the role of initial system-environment correlations on generation, evolution and transfer of the system quantum correlations. Finally，we try to find a general measure for the degree of environmental non-Markovianity, and clear how to make the most quantum information flow from environment to quantum system by modifying the physical parameters. The study of this project can provide some useful references for the application of quantum entanglement, quantum discord and environmental non-Markvianity in the practical quantum information process.

实际量子信息系统中环境导致的局域退相干会破坏系统的量子关联，限制量子关联态在实际量子信息处理中的应用，如何避免或抑制系统量子关联态的破坏是一个重要课题。本项目首先通过研究精确可解的物理模型来比较纠缠在不同环境下的动力学特征，寻找抑制解纠缠或纠缠保持的参数区，揭示量子信息过程中最优参数的物理体系；然后探索系统与环境初始关联对系统量子关联态（quantum discord）的产生、演化以及转移过程的影响。最后寻找度量环境非马尔科夫性更普适的物理量，弄清哪些物理参数可以调控环境非马尔科夫性，以使流入环境的信息能够最大程度的流回量子系统本身。本项目的研究将能为纠缠、quantum discord 以及环境非马尔科夫性在量子信息中的实际应用提供有益的参考。

实际量子信息系统中环境导致的局域退相干会破坏系统的量子关联，限制量子关联态在实际量子信息处理中的应用。如何保护和调控量子关联态是一个重要课题。本项目首先研究了精确可解的光子禁带模型下系统纠缠俘获行为，比较了三种不同的比特-环境退相干信道对初始纠缠俘获的影响，并给出获得较大纠缠俘获的条件，揭示了量子信息过程中最优纠缠俘获的物理体系；然后基于弱测量和量子反转测量，本项目提出了一个可以使量子系统纠缠得到最大俘获的机制，发现通过调整测量强度可以在保证一定的成功几率的情况下得到最优的纠缠俘获现象。本项目是我们前期工作的扩展和深入，其实施将能为量子纠缠在实际量子系统中的调控研究提供有力的理论参考。