Activation of monogamy in non-locality using local contextuality

TL;DR

This paper introduces a graph-theoretic framework to unify monogamy phenomena in Bell and non-contextuality inequalities, showing how local contextuality can activate monogamy in non-local correlations and revealing new trade-offs and monogamy relations.

Contribution

It presents a novel method to activate monogamy in Bell inequalities via local contextuality, unifying different non-locality phenomena and discovering new resource trade-offs.

Findings

Bell inequalities can be made monogamous by adding local contextuality terms.

Two-party Bell expressions can become non-trivial with a third-party measurement.

New monogamy relations are derived for no-signaling correlations.

Abstract

A unified view on the phenomenon of monogamy exhibited by Bell inequalities and non-contextuality inequalities arising from the no-signaling and no-disturbance principles is presented using the graph-theoretic method introduced in \textit{Phys. Rev. Lett. 109, 050404 (2012)}. We propose a novel type of trade-off, namely Bell inequalities that do not exhibit monogamy features of their own can be activated to be monogamous by the addition of a local contextuality term. This is illustrated by means of the well-known $\mathcal{I}_{3322}$ inequality, and reveals a resource trade-off between bipartite correlations and the local purity of a single system. In the derivation of novel no-signaling monogamies, we uncover a new feature, namely that two-party Bell expressions that are trivially classically saturated can become non-trivial upon the addition of an expression involving a third party with a single measurement input.