Cosmic Bell Test: Measurement Settings from Milky Way Stars
Name
PhysRevLett.118.060401.pdf
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1.44 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Handsteiner, Johannes
Rauch, Dominik
Gallicchio, Jason
Liu, Bo
Hosp, Hannes
Kofler, Johannes
Bricher, David
Fink, Matthias
Leung, Calvin
Nguyen, Hien T.
Date Issued
February 2017
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Handsteiner, Johannes et al. “Cosmic Bell Test: Measurement Settings from Milky Way Stars.” Physical Review Letters 118.6 (2017): n. pag. © 2017 American Physical Society
Version
Final published version
Abstract
Bell’s theorem states that some predictions of quantum mechanics cannot be reproduced by a local-realist theory. That conflict is expressed by Bell’s inequality, which is usually derived under the assumption that there are no statistical correlations between the choices of measurement settings and anything else that can causally affect the measurement outcomes. In previous experiments, this “freedom of choice” was addressed by ensuring that selection of measurement settings via conventional “quantum random number generators” was spacelike separated from the entangled particle creation. This, however, left open the possibility that an unknown cause affected both the setting choices and measurement outcomes as recently as mere microseconds before each experimental trial. Here we report on a new experimental test of Bell’s inequality that, for the first time, uses distant astronomical sources as “cosmic setting generators.” In our tests with polarization-entangled photons, measurement settings were chosen using real-time observations of Milky Way stars while simultaneously ensuring locality. Assuming fair sampling for all detected photons, and that each stellar photon’s color was set at emission, we observe statistically significant ≳7.31σ and ≳11.93σ violations of Bell’s inequality with estimated p values of ≲1.8×10[superscript -13] and ≲4.0×10[superscript -33], respectively, thereby pushing back by ∼600 years the most recent time by which any local-realist influences could have engineered the observed Bell violation.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Program in Science, Technology and Society
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Creative Commons Attribution
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.118.060401
