Institute for Quantum Optics and Quantum Information, Austrian Academy of Sciences, Boltzmanngasse 3, 1090 Vienna, Austria.
Proc Natl Acad Sci U S A. 2010 Nov 16;107(46):19708-13. doi: 10.1073/pnas.1002780107. Epub 2010 Nov 1.
Bell's theorem shows that local realistic theories place strong restrictions on observable correlations between different systems, giving rise to Bell's inequality which can be violated in experiments using entangled quantum states. Bell's theorem is based on the assumptions of realism, locality, and the freedom to choose between measurement settings. In experimental tests, "loopholes" arise which allow observed violations to still be explained by local realistic theories. Violating Bell's inequality while simultaneously closing all such loopholes is one of the most significant still open challenges in fundamental physics today. In this paper, we present an experiment that violates Bell's inequality while simultaneously closing the locality loophole and addressing the freedom-of-choice loophole, also closing the latter within a reasonable set of assumptions. We also explain that the locality and freedom-of-choice loopholes can be closed only within nondeterminism, i.e., in the context of stochastic local realism.
贝尔定理表明，局部现实理论对不同系统之间的可观察相关性施加了严格的限制，从而产生了贝尔不等式，该不等式可以在使用纠缠量子态的实验中被违反。贝尔定理基于现实性、局域性和在测量设置之间进行选择的自由等假设。在实验测试中，会出现“漏洞”，允许通过局部现实理论来解释所观察到的违反情况。在同时关闭所有这些漏洞的情况下违反贝尔不等式，是当今基础物理学中最具挑战性的问题之一。在本文中，我们提出了一个实验，该实验在违反贝尔不等式的同时，同时关闭局域性漏洞并解决选择自由性漏洞，并且在后一个漏洞方面也在合理的假设范围内进行了关闭。我们还解释了局域性和选择自由性漏洞只能在非决定论中关闭，即在随机局部现实主义的上下文中。
