# Information Security and Cryptography Research Group

## Nonlocality is Transitive

### Sandro Coretti, Esther Hänggi, and Stefan Wolf

Phys. Rev. Lett., American Physical Society, vol. 107, pp. 100402, Aug 2011.

We show a transitivity property of nonlocal correlations: There exist tripartite nonsignaling correlations of which the bipartite marginals between A and B as well as B and C are nonlocal and any tripartite nonsignaling system between A, B, and C consistent with them must be such that the bipartite marginal between A and C is also nonlocal. This property represents a step towards ruling out certain alternative models for the explanation of quantum correlations such as hidden communication at finite speed. Whereas it is not possible to rule out this model experimentally, it is the goal of our approach to demonstrate this explanation to be logically inconsistent: either the communication cannot remain hidden, or its speed has to be infinite. The existence of a three-party system that is pairwise nonlocal is of independent interest in the light of the monogamy property of nonlocality.

## BibTeX Citation

@article{CoHaWo11,
author       = {Sandro Coretti and Esther Hänggi and Stefan Wolf},
title        = {Nonlocality is Transitive},
journal      = {Phys. Rev. Lett.},
pages        = 100402,
volume       = 107,
year         = 2011,
month        = 8,
publisher    = {American Physical Society},
}