论文标题
在不忠的国家检测纠缠
Detecting Entanglement in Unfaithful States
论文作者
论文摘要
纠缠证人是一种有效的方法，可以在不进行完整断层扫描的情况下检测未知州的纠缠。目击纠缠的最广泛的方案之一是衡量其相对于纯粹的纠缠状态的忠诚。最近，在Phys.rev.lett \ textbf {124}，200502（2020）中发现了一大批无法用忠实见证人检测到的纠缠状态。他们被称为不忠的国家。在本文中，我们提出了一种通过测量结果来计算纠缠的下限来检测纠缠的新方法。数值模拟表明，我们的方法可以通过少量测量来检测不忠实的纠缠。此外，我们将我们的计划推广到多方状态，并表明它可以比以前具有相同数量的测量设置的纠缠证人运营商忍受更高的噪声。
Entanglement witness is an effective method to detect entanglement in unknown states without doing full tomography. One of the most widespread schemes of witnessing entanglement is measuring its fidelity with respect to a pure entangled state. Recently, a large class of states whose entanglement can not be detected with the fidelity witness has been discovered in Phys.Rev.Lett \textbf{124},200502(2020). They are called unfaithful states. In this paper we propose a new way to detect entanglement by calculating the lower bound of entanglement using measurement results. Numerical simulation shows our method can detect entanglement in unfaithful states with a small number of measurements. Moreover, we generalize our scheme to multipartite states and show that it can tolerate higher noise than previous entanglement witness operators with same number of measurement settings.
