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Main Authors: Contreras-Tejada, Patricia, Scarpa, Giannicola, Kubicki, Aleksander M., Brandenburger, Adam, La Mura, Pierfranceso
Format: Preprint
Published: 2021
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Online Access:https://arxiv.org/abs/2102.08966
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author Contreras-Tejada, Patricia
Scarpa, Giannicola
Kubicki, Aleksander M.
Brandenburger, Adam
La Mura, Pierfranceso
author_facet Contreras-Tejada, Patricia
Scarpa, Giannicola
Kubicki, Aleksander M.
Brandenburger, Adam
La Mura, Pierfranceso
contents Is the world quantum? An active research line in quantum foundations is devoted to exploring what constraints can rule out the postquantum theories that are consistent with experimentally observed results. We explore this question in the context of epistemics, and ask whether agreement between observers can serve as a physical principle that must hold for any theory of the world. Aumann's seminal Agreement Theorem states that two observers (of classical systems) cannot agree to disagree. We propose an extension of this theorem to no-signaling settings. In particular, we establish an Agreement Theorem for observers of quantum systems, while we construct examples of (postquantum) no-signaling boxes where observers can agree to disagree. The PR box is an extremal instance of this phenomenon. These results make it plausible that agreement between observers might be a physical principle, while they also establish links between the fields of epistemics and quantum information that seem worthy of further exploration.
format Preprint
id arxiv_https___arxiv_org_abs_2102_08966
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Observers of quantum systems cannot agree to disagree
Contreras-Tejada, Patricia
Scarpa, Giannicola
Kubicki, Aleksander M.
Brandenburger, Adam
La Mura, Pierfranceso
Quantum Physics
Is the world quantum? An active research line in quantum foundations is devoted to exploring what constraints can rule out the postquantum theories that are consistent with experimentally observed results. We explore this question in the context of epistemics, and ask whether agreement between observers can serve as a physical principle that must hold for any theory of the world. Aumann's seminal Agreement Theorem states that two observers (of classical systems) cannot agree to disagree. We propose an extension of this theorem to no-signaling settings. In particular, we establish an Agreement Theorem for observers of quantum systems, while we construct examples of (postquantum) no-signaling boxes where observers can agree to disagree. The PR box is an extremal instance of this phenomenon. These results make it plausible that agreement between observers might be a physical principle, while they also establish links between the fields of epistemics and quantum information that seem worthy of further exploration.
title Observers of quantum systems cannot agree to disagree
topic Quantum Physics
url https://arxiv.org/abs/2102.08966