Beyond Bell's theorem: correlation scenarios
Abstract
Bell's theorem witnesses that the predictions of quantum theory cannot be reproduced by theories of local hidden variables in which observers can choose their measurements independently of the source. Working out an idea of Branciard, Rosset, Gisin and Pironio, we consider scenarios which feature several sources, but no choice of measurement for the observers. Every Bell scenario can be mapped into such a correlation scenario, and Bell's theorem then discards those local hidden variable theories in which the sources are independent. However, most correlation scenarios do not arise from Bell scenarios, and we describe examples of (quantum) nonlocality in some of these scenarios, while posing many open problems along the way. Some of our scenarios have been considered before by mathematicians in the context of causal inference.
 Publication:

New Journal of Physics
 Pub Date:
 October 2012
 DOI:
 10.1088/13672630/14/10/103001
 arXiv:
 arXiv:1206.5115
 Bibcode:
 2012NJPh...14j3001F
 Keywords:

 Quantum Physics
 EPrint:
 new title and abstract, introduction updated, main text and results the same. To appear in New J. Phys