Enhancing Gravitational Interaction between Quantum Systems by a Massive Mediator

TL;DR

This paper proposes using a massive mediator to amplify gravitational interactions between quantum systems, reducing experimental challenges and making tests of quantum gravity more feasible.

Contribution

It introduces a novel approach of employing a massive body as an amplifying mediator to enhance gravitational interactions between quantum systems, independent of the mediator's initial state.

Findings

Interaction strength increases with mediator mass

Effective interaction is independent of mediator's initial state

Reduces requirements on test system delocalization

Abstract

In 1957 Feynman suggested that the quantum/classical character of gravity may be assessed by testing the gravitational interaction due to source masses in superposition. However, in all proposed experimental realisations using matter-wave interferometry the extreme weakness of this interaction requires pure initial states with extreme squeezing to achieve measurable effects of non-classical interaction for reasonable experiment durations. In practice, the systems that can be prepared in such nonclassical states are limited to small masses, which in turn limits the strength of their interaction. Here we address this key challenge--the weakness of gravitational interaction--by using a massive body as an amplifying mediator of gravitational interaction between two test systems. Our analysis shows that this results in an effective interaction between the two test-systems that grows with the mass of the mediator, is independent of its initial state and, therefore, its temperature. This greatly reduces the requirement on the mass and degree of delocalization of the test systems and, while still highly challenging, brings experiments on gravitational source masses a step closer to reality.