Universität zu Köln

Chaves, R., Cavalcanti, D. and Aolita, L. (2017). Causal hierarchy of multipartite Bell nonlocality. Quantum, 1. WIEN: VEREIN FORDERUNG OPEN ACCESS PUBLIZIERENS QUANTENWISSENSCHAF. ISSN 2521-327X

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Abstract

As with entanglement, different forms of Bell nonlocality arise in the multipartite scenario. These can be defined in terms of relaxations of the causal assumptions in local hidden-variable theories. However, a characterisation of all the forms of multipartite nonlocality has until now been out of reach, mainly due to the complexity of generic multipartite causal models. Here, we employ the formalism of Bayesian networks to reveal connections among different causal structures that make a both practical and physically meaningful classification possible. Our framework holds for arbitrarily many parties. We apply it to study the tripartite scenario in detail, where we fully characterize all the nonlocality classes. Remarkably, we identify new highly nonlocal causal structures that cannot reproduce all quantum correlations. This shows, to our knowledge, the strongest form of quantum multipartite nonlocality known to date. Finally, as a by-product result, we derive a non-trivial Bell type inequality with no quantum violation. Our findings constitute a significant step forward in the understanding of multipartite Bell nonlocality and open several venues for future research.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Chaves, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Cavalcanti, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Aolita, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-244191
DOI:	10.22331/q-2017-08-04-23
Journal or Publication Title:	Quantum
Volume:	1
Date:	2017
Publisher:	VEREIN FORDERUNG OPEN ACCESS PUBLIZIERENS QUANTENWISSENSCHAF
Place of Publication:	WIEN
ISSN:	2521-327X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language QUANTUM; ENTANGLEMENT; THEOREM Multiple languages Quantum Science & Technology; Physics, Multidisciplinary Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/24419