Simple method for experimentally testing any form of quantum contextuality

TL;DR

This paper introduces a simple, robust experimental method using two-point correlations of compatible observables to detect any form of quantum contextuality, facilitating easier exploration of nonclassical quantum phenomena.

Contribution

It demonstrates that two-point correlations suffice to reveal all forms of quantum contextuality, simplifying experimental procedures and connecting contextuality to quantum communication and computation.

Findings

Two-point correlations can detect all forms of contextuality.

The method is more robust and easier to implement experimentally.

It links contextuality to quantum communication complexity.

Abstract

Contextuality provides a unifying paradigm for nonclassical aspects of quantum probabilities and resources of quantum information. Unfortunately, most forms of quantum contextuality remain experimentally unexplored due to the difficulty of performing sequences of projective measurements on individual quantum systems. Here we show that two-point correlations between binary compatible observables are sufficient to reveal any form of contextuality. This allows us to design simple experiments that are more robust against imperfections and easier to analyze, thus opening the door for observing interesting forms of contextuality, including those requiring quantum systems of high dimensions. In addition, it allows us to connect contextuality to communication complexity scenarios and reformulate a recent result relating contextuality and quantum computation.