Cosmic Bell Test: Measurement Settings from Milky Way Stars<\/a><\/p>\n\n\n\nPhysical Review Letters 118, 060401 (2017)<\/p>\n\n\n\n
Abstract<\/h2>\n\n\n\n
Bell\u2019s theorem states that some predictions of quantum mechanics cannot be reproduced by a local-realist theory. That conflict is expressed by Bell\u2019s 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 \u201cfreedom of choice\u201d was addressed by ensuring that selection of measurement settings via conventional \u201cquantum random number generators\u201d 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\u2019s inequality that, for the first time, uses distant astronomical sources as \u201ccosmic setting generators.\u201d 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\u2019s color was set at emission, we observe statistically significant \u22737.31\u2062 and \u227311.93\u2062 violations of Bell\u2019s inequality with estimated values of \u22721.8\u00d710\u221213 and \u22724.0 \u00d710\u221233, respectively, thereby pushing back by \u223c600 years the most recent time by which any local-realist influences could have engineered the observed Bell violation.<\/p>\n","protected":false},"excerpt":{"rendered":"
Johannes Handsteiner, Andrew S. Friedman, Dominik Rauch, Jason Gallicchio*, Bo Liu, Hannes Hosp, Johannes Kofler, David Bricher, Matthias Fink, Calvin […]<\/p>\n","protected":false},"author":1,"featured_media":0,"template":"","publication_author":[16],"class_list":["post-6449","physics_publications","type-physics_publications","status-publish","hentry","publication_author-gallicchio"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/physics_publications\/6449","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/physics_publications"}],"about":[{"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/types\/physics_publications"}],"author":[{"embeddable":true,"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/users\/1"}],"wp:attachment":[{"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/media?parent=6449"}],"wp:term":[{"taxonomy":"publication_author","embeddable":true,"href":"https:\/\/www.hmc.edu\/physics\/wp-json\/wp\/v2\/publication_author?post=6449"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}