任意纠缠测量下探测效率极低的网络导引
Network steering with arbitrarily low detection efficiency of any entangled measurement
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中文总结 AI 辅助
该研究提出网络中的交换导引，可在任意非零探测效率下实现，能关闭量子导引实验的探测漏洞与自由意志漏洞。
中文摘要 AI 辅助
量子非定域性及其非对称对应物量子导引是量子力学最引人入胜的表现形式之一。从理论角度看，它们不仅具有基础意义，还在广泛应用中展现出潜力。然而，无漏洞实验观测的严格技术要求，使其实现多局限于基础演示。这些装置的一大挑战是现有探测器的探测效率有限：在标准场景中观测非定域性或导引，需要探测器达到某一临界效率，这仅能通过超导探测器实现。针对最简单的量子网络，本文证明，若网络中的源生成的态达到当前实际范围内的临界可见度，两方间的量子导引可在任意非零探测效率下实现，这种网络中的量子导引被称为交换导引。此外，当源为理想源时，即使探测效率极低，也可通过对不可信侧的任意纠缠测量观测到交换导引。因此，采用网络实现的量子导引实验可轻松关闭探测漏洞和自由意志漏洞这两大漏洞。
英文摘要
Quantum nonlocality and its asymmetric counterpart, quantum steering, are among the most intriguing manifestations of quantum mechanics. From a theoretical perspective, they are not only of fundamental significance but also hold promise for a wide range of applications. However, the stringent technological requirements for their experimental observation in a loophole-free way have largely restricted their realization to foundational demonstrations. A major challenge in these setups is the limited detection efficiency of current detectors as to observe nonlocality or steering in the standard scenarios, one requires detectors above a certain critical efficiency which can only be achieved with superconducting detectors. Considering the simplest quantum network, we demonstrate here that quantum steering between two parties, can be demonstrated for any non-zero detection efficiency, if the sources in the network generate states above a critical visibility well-within the current practical limits. This form of quantum steering in networks, is termed swap-steering. Moreover, when the sources are perfect, swap-steering can be observed using any entangled measurement on the untrusted side, even with arbitrarily low detection efficiency. Consequently, two major loopholes, the detection-loophole as well as free-will loophole can be closed easily in quantum steering experiments, when implemented using networks.
