Trade-off relations between Bell nonlocality and local Kochen-Specker contextuality in generalized Bell scenarios

TL;DR

This paper investigates the fundamental trade-off between Bell nonlocality and local Kochen-Specker contextuality in generalized Bell scenarios, revealing that both resources cannot be maximized simultaneously and exploring their interrelation through inequalities and quantifiers.

Contribution

It establishes a quantitative trade-off relation between Bell nonlocality and local contextuality in generalized scenarios, clarifying their joint limitations and broader implications.

Findings

Existence of a trade-off relation between Bell nonlocality and local contextuality.

Both resources cannot be arbitrarily large simultaneously.

The trade-off can be expressed through inequalities and quantifiers.

Abstract

The relations between Bell nonlocality and Kochen-Specker contextuality have been subject of research from many different perspectives in the last decades. Recently, some interesting results on these relations have been explored in the so-called generalized Bell scenarios, that is, scenarios where Bell spatial separation (or agency independence) coexist with (at least one of the) parties' ability to perform compatible measurements at each round of the experiment. When this party has an $n$-cycle compatiblity setup, it was first claimed that Bell nonlocality could not be concomitantly observed with contextuality at this party's local experiment. However, by a more natural reading of the definition of locality, it turns out that both Bell nonlocality and local contextuality can, in fact, be jointly present. In spite of it, in this work we prove that there cannot be arbitrary amounts of both of these two resources together. That is, we show the existence of a trade-off relation between Bell nonlocality and local contextuality in such scenarios. We explore this trade-off both in terms of inequalities and quantifiers, and we discuss how it can be understood in terms of a `global' notion of contextuality. Furthermore, we show that such notion does not only encompass local contextuality and Bell nonlocality, but also other forms of nonclassical correlations.