论文标题
纠缠估算的实验检查
Experimental Examination of Entanglement Estimates
论文作者
论文摘要
最近，发现了针对三质量纯状态的适当的真实多部分纠缠（GME）措施[见Xie和Eberly，Phys。莱特牧师。 127，040403（2021）]，但捕获混合国家的有用纠缠措施仍然是一个开放的挑战。到目前为止，它不仅需要实验中的完整断层扫描，而且还需要巨大的计算劳动。 Gühne，Reimpell和Werner [Phys。莱特牧师。 98，110502（2007）]，他使用纠缠证人的期望值来描述纠缠的下限估计。我们在这里提供了一个扩展，还提供了真正的纠缠上限。此进步仅需要{\ em any}赫米尔式操作员的期望值。此外，我们确定了一类运算符$ \ a_1 $的类别，该$ \ a_1 $不仅给出了良好的估计，而且还需要少量的实验测量值。在本说明中，我们定义了我们的方法，并通过估计我们最近实验中准备的许多纯净和混合状态的纠缠措施来说明它。
Recently a proper genuine multipartite entanglement (GME) measure has been found for three-qubit pure states [see Xie and Eberly, Phys. Rev. Lett. 127, 040403 (2021)], but capturing useful entanglement measures for mixed states has remained an open challenge. So far, it requires not only a full tomography in experiments, but also huge calculational labor. A leading proposal was made by Gühne, Reimpell, and Werner [Phys. Rev. Lett. 98, 110502 (2007)], who used expectation values of entanglement witnesses to describe a lower bound estimation of entanglement. We provide here an extension that also gives genuine upper bounds of entanglement. This advance requires only the expectation value of {\em any} Hermitian operator. Moreover, we identify a class of operators $\A_1$ which not only give good estimates, but also require a remarkably small number of experimental measurements. In this note we define our approach and illustrate it by estimating entanglement measures for a number of pure and mixed states prepared in our recent experiments.
