Gravitational Aharonov-Bohm Interferometer
In the Aharonov-Bohm (AB) effect in electromagnetism, the phase shift in the wavefunction of a particle in an electrostatic potential, V, is measured even in the absence of a classical electrostatic force. The gravitational analogue of this involves a phase shift due to a gravitational potential, U, in the absence of a gravitational force. Unlike the electromagnetic AB effect, to date there has been no experimental demonstration of the gravitational AB effect.
A laboratory based experiment to measure the gravitational AB effect has been proposed by Hohensee, Zeilinger et al [arXiv:1109.4887]. The experiment utilises cold atoms. Each atom is prepared in a linear superposition two quantum states which are subsequently held by optical lattices in the arms of a Mach-Zhender interferometer. Source masses are then introduced to create a region where the force from gravitational field generating masses vanishes. The experiment is designed to ensure that other contributions to the phase shifts are either identical for both arms of the interferometer or removed. Consequently, the resultant phase shift induced in the matter wave is due to the gravitational potential. We are going to carry out a feasibility study of this experiment.