论文标题
任意的许多独立观察者可以共享单个最大纠缠量子对的非局部性
Arbitrarily many independent observers can share the nonlocality of a single maximally entangled qubit pair
论文作者
论文摘要
爱丽丝和鲍勃分别有一对纠缠量子的一半。鲍勃（Bob）测量了他的一半，然后将他的Qubit转移到了第二个鲍勃（Bob），后者再次测量。目的是最大程度地增加可能违反Clauser-Horne-Hornimony-Holt（CHSH）Bell与单一爱丽丝的鲍尔·霍尔（Chsh）钟声的鲍勃数量。这种情况是在[Phys。莱特牧师。 114，250401（2015）]作者提到的证据表明，当鲍勃独立起作用并没有偏见的投入时，最多两个人都可以期望违反与爱丽丝的CHSH不平等。在这里，我们表明，与这一证据相反，任意许多独立的鲍勃可能会对单一爱丽丝造成预期的CHSH侵犯。我们的证明是建设性的，我们的测量策略可以推广到与较大类别的两级状态一起使用，这些状态包括所有纯粹的纠结的两分位国家。由于违反铃铛不等式对于独立于设备的任务是必要的，因此我们的工作代表了对最终了解限制的局限性，可以从一对量子台上牢固地产生限制。
Alice and Bob each have half of a pair of entangled qubits. Bob measures his half and then passes his qubit to a second Bob who measures again and so on. The goal is to maximize the number of Bobs that can have an expected violation of the Clauser-Horne-Shimony-Holt (CHSH) Bell inequality with the single Alice. This scenario was introduced in [Phys. Rev. Lett. 114, 250401 (2015)] where the authors mentioned evidence that when the Bobs act independently and with unbiased inputs then at most two of them can expect to violate the CHSH inequality with Alice. Here we show that, contrary to this evidence, arbitrarily many independent Bobs can have an expected CHSH violation with the single Alice. Our proof is constructive and our measurement strategies can be generalized to work with a larger class of two-qubit states that includes all pure entangled two-qubit states. Since violation of a Bell inequality is necessary for device-independent tasks, our work represents a step towards an eventual understanding of the limitations on how much device-independent randomness can be robustly generated from a single pair of qubits.
