Quantum correlations with no causal order

Oreshkov, Ognyan, Costa, Fabio and Brukner, Caslav (2012) Quantum correlations with no causal order. Nature Communications, 3 . doi:10.1038/ncomms2076

Author Oreshkov, Ognyan
Costa, Fabio
Brukner, Caslav
Title Quantum correlations with no causal order
Journal name Nature Communications   Check publisher's open access policy
ISSN 2041-1723
Publication date 2012-10-02
Year available 2012
Sub-type Article (original research)
DOI 10.1038/ncomms2076
Open Access Status DOI
Volume 3
Total pages 8
Place of publication London, United Kingdom
Publisher Nature Publishing Group
Language eng
Abstract The idea that events obey a definite causal order is deeply rooted in our understanding of the world and at the basis of the very notion of time. But where does causal order come from, and is it a necessary property of nature? Here, we address these questions from the standpoint of quantum mechanics in a new framework for multipartite correlations that does not assume a pre-defined global causal structure but only the validity of quantum mechanics locally. All known situations that respect causal order, including space-like and time-like separated experiments, are captured by this framework in a unified way. Surprisingly, we find correlations that cannot be understood in terms of definite causal order. These correlations violate a 'causal inequality' that is satisfied by all space-like and time-like correlations. We further show that in a classical limit causal order always arises, which suggests that space-time may emerge from a more fundamental structure in a quantum-to-classical transition.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Mathematics and Physics
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Citation counts: TR Web of Science Citation Count  Cited 49 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 49 times in Scopus Article | Citations
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