Testing the gravitomagnetic clock effect on the Earth with neutron interferometry

Abstract

The general relativistic gravitomagnetic clock effect consists in the fact that two point particles orbiting a central spinning object along identical, circular equatorial geodesic paths, but in opposite directions, exhibit a time difference in describing a full revolution. It turns out that the particle rotating in the same sense of the central body is slower than the particle rotating in the opposite sense. In this paper it is proposed to measure such effect in an Earth laboratory experiment involving interferometry of slow neutrons. With a sphere of 2.5 cm radius and spinning at 4.3 x 10^4 rad/s as central source, and using neutrons with wavelength of 1 Angstrom it should be possible to obtain, for a given sense of rotation of the central source, a phase shift of 0.18 rad, well within the experimental sensitivity. By reversing the sense of rotation of the central body it should be possible to obtain a 0.06 fringe shift.