Covariance Bell inequalities

Article Article scientifique Article Covariance Bell inequalities eng 2017 author Pozsgay Victor 816657 author Hirsch Flavien 660781 author Branciard Cyril 628166 author Brunner Nicolas 510523 10.1103/PhysRevA.96.062128 1050-2947 https://link.aps.org/doi/10.1103/PhysRevA.96.062128 We introduce Bell inequalities based on covariance, one of the most common measures of correlation. Explicit examples are discussed, and violations in quantum theory are demonstrated. A crucial feature of these covariance Bell inequalities is their nonlinearity; this has nontrivial consequences for the derivation of their local bound, which is not reached by deterministic local correlations. For our simplest inequality, we derive analytically tight bounds for both local and quantum correlations. An interesting application of covariance Bell inequalities is that they can act as "shared randomness witnesses": specifically, the value of the Bell expression gives device-independent lower bounds on both the dimension and the entropy of the shared random variable in a local model. Dewey 500.2 35 Groupe de physique appliquée 135 false 801 Groupe Brunner Physical Review. A 96 062128 c08717a7-f77c-42c7-9f8a-a9c4ef414419 Article (Accepted version) Public 1710.02445.pdf 611335 application/pdf openAccess Faculté des sciences / Section de physique / Groupe de physique appliquée

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Covariance Bell inequalities	Physical Review. A			2017	353	403

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Pozsgay, Victor