Bound on genuine multipartite correlations from the principle of information causality

TL;DR

This paper extends the principle of information causality to genuine multipartite correlations, showing that the quantum bounds on these correlations are consistent with this principle, thus helping to define the limits of quantum correlations.

Contribution

It generalizes the information causality principle to multipartite correlations and demonstrates that quantum bounds are consistent with this principle for genuine multipartite entanglement.

Findings

Maximal genuine multipartite correlations match quantum bounds.

Information causality constrains multipartite correlations.

Quantum theory's bounds are consistent with the principle.

Abstract

Quantum mechanics is not the unique no-signaling theory which is endowed with stronger-than-classical correlations, and there exists a broad class of no-signaling theories allowing even stronger-than-quantum correlations. The principle of information causality has been suggested to distinguish quantum theory from these nonphysical theories, together with an elegant information-theoretic proof of the quantum bound of two-particle correlations. In this work, we extend this to genuine $N$-particle correlations that cannot be reduced to mixtures of states in which a smaller number of particles are entangled. We first express Svetlichny's inequality in terms of multipartite no-signaling boxes, then prove that the strongest genuine multipartite correlations lead to the maximal violation of information causality. The maximal genuine multipartite correlations under the constraint of information causality is found to be equal to the quantum mechanical bound. This result consolidates information causality as a physical principle defining the possible correlations allowed by nature, and provides intriguing insights into the limits of genuine multipartite correlations in quantum theory.