Reservations on Cahill's Quantum Gravity Experiment

J. ay R. Seaver

Fernando Sansò, Federica Migliaccio

JOHN ARCHIBALD WHEELER

Oded Barash, Itzhack Dana

The experimental study of cold atoms kicked by a pulsed optical standing wave and falling under gravity has led to the important discovery of the accelerator modes (QAMs). It is shown that QAMs in the absence of gravity can feature a rotational quasiregularity which cannot be found in the usual QAMs. Thus, QAMs with non-accelerating quasiregular segments may be used to control the quantum motion of atoms in a way which is not possible in the presence of gravity. Copyright © 2007 Praise Worthy Prize S.r.l. - All rights reserved.

Eduardo Martín-Martínez, Tales Rick Perche

We revisit the Bose-Marletto-Vedral (BMV) tabletop 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 modeling 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 local mediators in the gravitational field.

Dean P. Rickles, Xerxes D. Arsiwalla, Hatem Elshatlawy