论文标题
界面的绑定纠缠单线状态量子状态
Bound entangled singlet-like states for quantum metrology
论文作者
论文摘要
双分部分纠缠的量子状态具有阳性部分转置（PPT），即PPT纠缠状态，通常被认为是非常弱的纠缠。由于无法从中蒸馏出任何纯净的纠缠，因此它们也被称为绑定纠缠。在本文中，我们介绍了两类（$ 2D \ times 2d $） - 任何$ d \ ge 2 $的尺寸ppt纠缠状态，它们的表现明显优于所有可分离状态。我们提供了有力的证据，表明我们的国家为给定的系统规模提供了PPT状态可实现的最大计量学增益。当尺寸$ d $进入无限时，这些状态的计量学增益将变得最大，并等于一对最大纠缠量子的计量学增益。因此，我们认为我们的国家可以被称为“ PPT Singlets”。
Bipartite entangled quantum states with a positive partial transpose (PPT), i.e., PPT entangled states, are usually considered very weakly entangled. Since no pure entanglement can be distilled from them, they are also called bound entangled. In this paper we present two classes of ($2d\times 2d$)-dimensional PPT entangled states for any $d\ge 2$ which outperform all separable states in metrology significantly. We present strong evidence that our states provide the maximal metrological gain achievable by PPT states for a given system size. When the dimension $d$ goes to infinity, the metrological gain of these states becomes maximal and equals the metrological gain of a pair of maximally entangled qubits. Thus, we argue that our states could be called "PPT singlets."
