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arXiv · 2106.04065

Implications of Local Friendliness violation for quantum causality

Eric G. Cavalcanti·Howard M. Wiseman
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Abstract

We provide a new formulation of the Local Friendliness no-go theorem of Bong et al [Nat. Phys. 16, 1199 (2020)] from fundamental causal principles, providing another perspective on how it puts strictly stronger bounds on quantum reality than Bell's theorem. In particular, quantum causal models have been proposed as a way to maintain a peaceful coexistence between quantum mechanics and relativistic causality, while respecting Leibniz's methodological principle. This works for Bell's theorem but does not work for the Local Friendliness no-go theorem, which considers an extended Wigner's Friend scenario. More radical conceptual renewal is required; we suggest that cleaving to Leibniz's principle requires extending relativity to events themselves.

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Eric G. Cavalcanti, Howard M. Wiseman. 2021-06-08. Implications of Local Friendliness violation for quantum causality. https://doi.org/10.3390/e23080925

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