Classical Causal Models for Bell and Kochen-Specker Inequality Violations Require Fine-Tuning
Nonlocality and contextuality are at the root of conceptual puzzles in quantum mechanics, and they are key resources for quantum advantage in information-processing tasks. Bell nonlocality is best understood as the incompatibility between quantum correlations and the classical theory of causality, a...
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| Format: | Article |
| Language: | English |
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American Physical Society
2018-04-01
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| Series: | Physical Review X |
| Online Access: | http://doi.org/10.1103/PhysRevX.8.021018 |
| _version_ | 1818399634052087808 |
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| author | Eric G. Cavalcanti |
| author_facet | Eric G. Cavalcanti |
| author_sort | Eric G. Cavalcanti |
| collection | DOAJ |
| description | Nonlocality and contextuality are at the root of conceptual puzzles in quantum mechanics, and they are key resources for quantum advantage in information-processing tasks. Bell nonlocality is best understood as the incompatibility between quantum correlations and the classical theory of causality, applied to relativistic causal structure. Contextuality, on the other hand, is on a more controversial foundation. In this work, I provide a common conceptual ground between nonlocality and contextuality as violations of classical causality. First, I show that Bell inequalities can be derived solely from the assumptions of no signaling and no fine-tuning of the causal model. This removes two extra assumptions from a recent result from Wood and Spekkens and, remarkably, does not require any assumption related to independence of measurement settings—unlike all other derivations of Bell inequalities. I then introduce a formalism to represent contextuality scenarios within causal models and show that all classical causal models for violations of a Kochen-Specker inequality require fine-tuning. Thus, the quantum violation of classical causality goes beyond the case of spacelike-separated systems and already manifests in scenarios involving single systems. |
| first_indexed | 2024-12-14T07:23:47Z |
| format | Article |
| id | doaj.art-19de36b7e8fc4a7a9a61c3846029f465 |
| institution | Directory Open Access Journal |
| issn | 2160-3308 |
| language | English |
| last_indexed | 2024-12-14T07:23:47Z |
| publishDate | 2018-04-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review X |
| spelling | doaj.art-19de36b7e8fc4a7a9a61c3846029f4652022-12-21T23:11:33ZengAmerican Physical SocietyPhysical Review X2160-33082018-04-018202101810.1103/PhysRevX.8.021018Classical Causal Models for Bell and Kochen-Specker Inequality Violations Require Fine-TuningEric G. CavalcantiNonlocality and contextuality are at the root of conceptual puzzles in quantum mechanics, and they are key resources for quantum advantage in information-processing tasks. Bell nonlocality is best understood as the incompatibility between quantum correlations and the classical theory of causality, applied to relativistic causal structure. Contextuality, on the other hand, is on a more controversial foundation. In this work, I provide a common conceptual ground between nonlocality and contextuality as violations of classical causality. First, I show that Bell inequalities can be derived solely from the assumptions of no signaling and no fine-tuning of the causal model. This removes two extra assumptions from a recent result from Wood and Spekkens and, remarkably, does not require any assumption related to independence of measurement settings—unlike all other derivations of Bell inequalities. I then introduce a formalism to represent contextuality scenarios within causal models and show that all classical causal models for violations of a Kochen-Specker inequality require fine-tuning. Thus, the quantum violation of classical causality goes beyond the case of spacelike-separated systems and already manifests in scenarios involving single systems.http://doi.org/10.1103/PhysRevX.8.021018 |
| spellingShingle | Eric G. Cavalcanti Classical Causal Models for Bell and Kochen-Specker Inequality Violations Require Fine-Tuning Physical Review X |
| title | Classical Causal Models for Bell and Kochen-Specker Inequality Violations Require Fine-Tuning |
| title_full | Classical Causal Models for Bell and Kochen-Specker Inequality Violations Require Fine-Tuning |
| title_fullStr | Classical Causal Models for Bell and Kochen-Specker Inequality Violations Require Fine-Tuning |
| title_full_unstemmed | Classical Causal Models for Bell and Kochen-Specker Inequality Violations Require Fine-Tuning |
| title_short | Classical Causal Models for Bell and Kochen-Specker Inequality Violations Require Fine-Tuning |
| title_sort | classical causal models for bell and kochen specker inequality violations require fine tuning |
| url | http://doi.org/10.1103/PhysRevX.8.021018 |
| work_keys_str_mv | AT ericgcavalcanti classicalcausalmodelsforbellandkochenspeckerinequalityviolationsrequirefinetuning |