Delayed Choice Contextuality: A way to rule out Contextual Hidden Variables

TL;DR

This paper introduces experimental techniques to differentiate genuinely quantum systems from classical mimics that simulate quantum measurement statistics, addressing a key challenge in validating contextuality as a resource.

Contribution

It proposes methods to distinguish true quantum contextuality from classical hidden-variable models that imitate quantum behavior.

Findings

Developed techniques to identify genuine quantum contextuality

Demonstrated limitations of current tests in ruling out hidden-variable mimics

Enhanced reliability of contextuality as an operational quantum resource

Abstract

A PhD student is locked inside a box, imitating a quantum system by mimicking the measurement statistics of any viable observable nominated by external observers. Inside a second box lies a genuine quantum system. Either box can be used to pass a test for contextuality - and from the perspective of an external observer, be operationally indistinguishable. There is no way to discriminate between the two boxes based on the output statistics of any contextuality test. This poses a serious problem for contextuality tests to be used as viable tests for device independent quantumness, and severely limits realistic use of contextuality as an operational resource. Here we rectify this problem by building experimental techniques for distinguishing a contextual system that is genuinely quantum, and one that mimics it through clever use of hidden variables.