What gravity mediated entanglement can really tell us about quantum gravity

TL;DR

This paper critically examines the BMV experiment proposal for detecting quantum gravity via gravity-mediated entanglement, questioning the assumptions about locality and the quantum nature of gravity involved.

Contribution

It provides a fully quantum model of matter-gravity interaction and analyzes how gravity-mediated entanglement could be explained without assuming quantum gravitational degrees of freedom.

Findings

Gravity mediated entanglement can be explained without quantum gravity assumptions.

Current BMV proposals may not definitively prove quantum gravity.

Modifications to BMV experiments could test quantum gravity without local mediator assumptions.

Abstract

We revisit the Bose-Marletto-Vedral (BMV) table-top experimental proposal - which aims to witness quantum gravity using gravity mediated entanglement - analyzing the role of locality in the experiment. We first carry out a fully quantum modelling of the interaction of matter and gravity and then show in what way gravity mediated entanglement in the BMV experiment could be accounted for without appealing to quantum degrees of freedom of the gravitational field. We discuss what assumptions are needed in order to interpret the current BMV experiment proposals as a proof of quantum gravity, and also identify the modifications that a BMV-like experiment could have in order to serve as proof of quantum gravity without having to assume the existence of a local mediators in the gravitational field.