User:Nonabelian/Gravitational Aharonov-Bohm Effect

The Gravitational Aharonov-Bohm (AB) effect is a quantum phenomenon where the wave function of a particle undergoes a phase shift in the presence of a gravitational potential, even when there is no classical force acting on the particle. This is analogous to the electromagnetic AB effect, where the wave function of a particle is shifted by an electrostatic (scalar) potential in the absence of any classical force field. The gravitational effect shares the features of its electromagnetic cousin in being nondispersive, non-local, and topological in nature: i.e. no number of local measurements at any location (e.g. by gravimeters) in which the particle is allowed to exist can predict the gravitostatic AB effect.

In 2022 the gravitational Aharonov-Bohm effect effect was observed experimentally for the first time. The observation was based on a test design first proposed in 2012. In the experiment, ultra-cold rubidium atoms in superposition were launched vertically inside a vacuum tube and split with a laser so that one part would go higher than the other and then recombined back. Outside of the chamber at the top sits a mass that changes the gravitational potential. Thus, the part that goes higher should experience a greater change which manifests as an interference pattern when the wave packets recombine resulting in a measurable phase shift.

Multiple other tests have been proposed.