Optimal measurements for tests of Einstein-Podolsky-Rosen steering with no detection loophole using two-qubit Werner states
Optimal measurements for tests of Einstein-Podolsky-Rosen steering with no detection loophole using two-qubit Werner states
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DOI：
10.1103/physreva.90.012114
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发表时间：
2014-04
影响因子：
2.9
通讯作者：
D. Evans;H. Wiseman
中科院分区：
文献类型：
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作者：
D. Evans;H. Wiseman
在早期的工作中已经表明，柏拉图固体的顶点是使用各向同性纠缠的量子比特对测试Einstein-Podolsky-罗森（EPR）转向的良好测量选择。这样的测量是有规律的间隔，测量多样性是一个很好的功能，使EPR操纵不平等更容易违反实验缺陷的存在。然而，这样的测量是证明次优。在这里，我们开发了一种方法，用于设计最佳策略的EPR转向测试，在这个意义上是最强大的混合物和低效率（同时仍然关闭检测漏洞，当然），对于一个给定的测量设置数n。我们允许任意的测量方向，并在EPR指导不等式的结果的任意权重。对于大n来说，这是一个困难的优化问题，因此我们还考虑在此限制下构造接近最优的EPR引导不等式的更实用的方法。
It has been shown in earlier works that the vertices of Platonic solids are good measurement choices for tests of Einstein-Podolsky-Rosen (EPR)-steering using isotropically entangled pairs of qubits. Such measurements are regularly spaced, and measurement diversity is a good feature for making EPR-steering inequalities easier to violate in the presence of experimental imperfections. However, such measurements are provably suboptimal. Here, we develop a method for devising optimal strategies for tests of EPR-steering, in the sense of being most robust to mixture and inefficiency (while still closing the detection loophole, of course), for a given number n of measurement settings. We allow for arbitrary measurement directions, and arbitrary weightings of the outcomes in the EPR-steering inequality. This is a difficult optimization problem for large n, so we also consider more practical ways of constructing near-optimal EPR-steering inequalities in this limit.