Experimental test of quantum contextuality in neutron interferometry

TL;DR

This paper reports an experimental test of quantum contextuality using neutron interferometry, demonstrating violation of noncontextual hidden variable theories through measured expectation values.

Contribution

It provides the first experimental verification of quantum contextuality in a neutron system using a Bell-like state and an inequality derived from the Peres-Mermin proof.

Findings

Violation of the inequality observed with a value of 2.291 +/- 0.008

Quantum predictions cannot be explained by noncontextual hidden variables

Experimental confirmation of quantum contextuality in neutron interferometry

Abstract

We performed an experimental test of the Kochen-Specker theorem based on an inequality derived from the Peres-Mermin proof, using spin-path (momentum) entanglement in a single neutron system. Following the strategy proposed by Cabello et al. [Phys. Rev. Lett. 100, 130404 (2008)], a Bell-like state was generated and three expectation values were determined. The observed violation 2.291 +/- 0.008 > 1 clearly shows that quantum mechanical predictions cannot be reproduced by noncontextual hidden variables theories.