Do small massive superpositions necessarily significantly entangle with gravity?

TL;DR

This paper examines whether small superpositions of mass necessarily lead to significant entanglement with gravity, questioning assumptions in proposed quantum gravity experiments.

Contribution

It clarifies that not all quantum models of gravity predict significant entanglement in mass superposition experiments.

Findings

Not all quantum gravity models imply significant entanglement.

Mass superpositions may not always produce measurable gravitational entanglement.

Implications for interpreting quantum gravity experiments.

Abstract

Christodoulou and Rovelli (CR) [1] have argued that a Bose et al.-Marletto-Vedral (BMV) experiment that confirmed the quantum nature of gravity would give laboratory evidence for a quantum superposition of spacetime geometries created in the course of the experiment. Hanif et al. [2] have argued that mass interferometers can be used to test whether gravity acts as a quantum entity when measured. We note that not all quantum models of gravity imply that mass superpositions necessarily become significantly entangled with any degrees of freedom of the gravitational field during the experiments discussed.