Violation of local realism with freedom of choice

Thomas Scheidl, Rupert Ursin, Johannes Kofler (Corresponding author), Sven Ramelow, Xiaosong Ma, Thomas Herbst, Lothar Ratschbacher, Alessandro Fedrizzi, Nathan Langford, Thomas Jennewein, Anton Zeilinger (Corresponding author)

Publications: Contribution to journalArticlePeer Reviewed

Abstract

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.
Original languageEnglish
Pages (from-to)19708-19713
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America (PNAS)
Volume107
Issue number46
DOIs
Publication statusPublished - 2010

Austrian Fields of Science 2012

  • 103026 Quantum optics

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