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arXiv · 1404.3348

Measurement sharpness cuts nonlocality and contextuality in every physical theory

G. Chiribella·X. Yuan
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Abstract

Gathering data through measurements is at the basis of every experimental science. Ideally, measurements should be repeatable and, when extracting only coarse-grained data, they should allow the experimenter to retrieve the finer details at a later time. However, in practice most measurements appear to be noisy. Here we postulate that, despite the imperfections observed in real life experiments, there exists a fundamental level where all measurements are ideal. Combined with the requirement that ideal measurements remain so when coarse-grained or applied in parallel on spacelike separated systems, our postulate places a powerful constraint on the amount of nonlocality and contextuality that can be found in an arbitrary physical theory, bringing down the violation of Bell and Kocher-Specker inequalities near to its quantum value. In addition, it provides a new compelling motivation for the principles of Local Orthogonality and Consistent Exclusivity, recently proposed for the characterization of the quantum set of probability distributions.

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G. Chiribella, X. Yuan. 2014-04-18. Measurement sharpness cuts nonlocality and contextuality in every physical theory. https://arxiv.org/abs/1404.3348

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