Quantum nonlocality in extended theories of gravity

TL;DR

This paper studies how curved spacetime in extended gravity theories affects quantum nonlocal correlations, showing that gravity suppresses Bell inequality violations, which can inform experimental tests of these theories.

Contribution

It quantifies the impact of extended gravity models on quantum nonlocality in massive particles within a weak-field approximation.

Findings

Curved spacetime suppresses Bell inequality violations.

Corrections to Einstein gravity further reduce quantum correlations.

Results applicable to both massive and massless particles.

Abstract

We investigate how pure-state Einstein-Podolsky-Rosen correlations in the internal degrees of freedom of massive particles are affected by a curved spacetime background described by extended theories of gravity. We consider models for which the corrections to the Einstein-Hilbert action are quadratic in the curvature invariants and we focus on the weak-field limit. We quantify nonlocal quantum correlations by means of the violation of the Clauser-Horne-Shimony-Holt inequality, and show how a curved background suppresses the violation by a leading term due to general relativity and a further contribution due to the corrections to Einstein gravity. Our results can be generalized to massless particles such as photon pairs and can thus be suitably exploited to devise precise experimental tests of extended models of gravity.