When can gravity path-entangle two spatially superposed masses?

An experimental test of quantum effects in gravity has recently been, where the ability of the gravitational field to entangle two masses used as a witness of its quantum nature. The key idea is that if gravity can entanglement between two masses then it must have at least some features (i.e., two non-commuting observables). Here we discuss what models for coupled matter and gravity predict for this experiment.-type models, and also quantum field theory in curved spacetime, as as various induced gravities, do not predict entanglement generation; they therefore be ruled out by observing entanglement in the experiment., local linearised quantum gravity models predict that the masses can entangled. We analyse the mechanism by which entanglement is established such models, modelling a gravity-assisted two-qubit gate.