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arXiv · 2108.03665

Leggett-type inequalities for testing nonlocal realism in multipartite systems

Abdul Sattar Khan·Ma-Cheng Yang·Cong-Feng Qiao
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Abstract

Nonlocal realism represents the last classical cornerstone in conflict with quantum theory, and has been shown to be largely untenable in bipartite systems [Nature 446, 871 (2007); Nature Physics 4, 681 (2008)]. We extend the Leggett-type nonlocal realistic model to arbitrary N-partite systems with polarizer settings, and derive rigorous inequalities that distinguish quantum predictions from nonlocal realistic theories. The derivation yields a fundamental double inequality that is universally valid, from which the Leggett-type bounds follow under specific measurement settings. As an illustration, we demonstrate quantum violations of these inequalities for Greenberger-Horne-Zeilinger (GHZ) states, with maximal violation 2(\sqrt{5}+1). Our results show that nonlocal realism in multipartite systems is experimentally testable.

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Abdul Sattar Khan, Ma-Cheng Yang, Cong-Feng Qiao. 2021-08-08. Leggett-type inequalities for testing nonlocal realism in multipartite systems. https://arxiv.org/abs/2108.03665

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