By Kent., A. & Pitalúa-García D.
Submitted to arXiv on 6 September 2021.
The Bose-Marletto-Vedral (BMV) experiment [S. Bose et al., Phys. Rev. Lett. 119, 240401 (2017); C. Marletto and V. Vedral, Phys. Rev. Lett. 119, 240402 (2017)] aims to demonstrate that spacetime is non-classical by observing entanglement generated by the gravitational field. However, local hidden variable theories can simulate any entangled correlations in any experiment — such as the BMV proposal — that does not involve measurements in spacelike separated wings. Here we propose to amplify the entanglement generated by the BMV experiment to distant quantum particles in a Bell experiment involving wings at spacelike separation. A violation of a Bell inequality in our proposed experiment would rule out local hidden variable explanations, providing a stronger proof of the non-classicality of spacetime than the original BMV proposal.