三体量子关联以及局域量子操作对两体量子关联的影响

In this project, we will study quantum correlations in tripartite systems and effects of local quantum operations on bipartite quantum correlations. For the former case, we will focus our attention on the total quantum correlation and the genuine quantum correlation as well as the relations of various correlations in the system or between/among subsystems. To be specific, using conditional entropies, we will propose two methods for studying various correlations in an arbitrary state of a tripartite system. Utilizing relative entropies, we will extend the method proposed in Phys.Rev.Lett.104（2010）080501 and put forward a new approach to study genuine classical and quantum correlations in any state of a tripartite system. We will explore the additivity relations and sources of various correlations retrieved with these methods and compare them concretely. For the latter case, we will first take advantage of some peculiar propeties of some special states (e.g., Werner/Bell diagonal states) and some currently popular quantum-correlation research methods to study the effects of local quantum operations on the bipartite quantum correlations. Afterwards, we will study the same issue by extending the concerned states. Works in this project will offer not only four different methods for studying various correlations in tripartite systems but also comprise of some concrete examples and comparisons among different methods, hence the project merits its important significance in exploring different theoretical research methods on correlations.

本项目研究三体量子关联以及局域量子操作对两体量子关联的影响。对于前者,我们着重探究总量子关联、真实全体量子关联及系统、子系统中(或间)各种关联的关系。基于条件熵我们将提出两种研究三体任意态中关联的方法；基于相对熵，我们把[PRL104(10)080501]中研究总量子关联的方法拓展用于研究真实全体关联，提出另一种研究三体量子比特系统中真实全体量子关联的新方法。我们探究各种关联的相加性关系及其起源并对各种方法进行比较。对于后者，我们将首先利用一些两体特殊态（Werner/Bell diagonal等等）的性质及当前流行的一些量子关联研究方法，研究局域量子操作对其量子关联的影响，之后拓展被研究态的范围。本项目研究不仅可提供研究三体系统中关联以及局域量子操作对两体量子关联影响的方法,还包含一些实例计算和不同方法计算结果比较，因此具有重要的关于量子系统中关联研究的理论方法探讨意义。

本项目研究了量子关联交换以及局域量子操作对两体量子关联的影响。利用当前流行的一些量子关联研究方法，研究了一些两体特殊态（Werner/Bell diagonal/Werner衍生态/qutrit态等等）的量子关联性质以及局域量子操作对其的影响。其次还把量子纠缠交换扩展到量子关联交换，进而提出量子关联中继器的概念。使用了四种著名的量子关联测量指标，即形成纠缠 、量子失协、测量扰动和改良的测量扰动来表征交换过程中的量子关联。我们揭示了所关心的量子关联的变化特性、阈值等，发现了两种不同的现象，通过分析讨论给出其物理解释。本项目研究不仅可提供研究一些系统中关联以及局域量子操作对两体量子关联影响的方法,还包含一些实例计算和不同方法计算结果比较，因此具有重要的关于量子系统中关联研究的理论方法探讨意义。