High precision measurement of the topological Aharonov–Casher effect with neutrons

Abstract

The phase shift predicted by Aharonov and Casher (AC) for a magnetic dipole diffracting around a line charge was first observed by Cimmino et al. using a neutron interferometer. A number of subsequent atom interferometry experiments have been performed to observe this effect. These experiments measured the v× E phase shift due to the magnetic field induced in the rest frame of the atom, with no indication of the topological nature of the AC interaction. We intend to perform a high precision AC experiment with neutrons to improve the accuracy of our previous results and to highlight the topological nature of the effect. Finally, we present a novel geometry to achieve a spin-dependent magnetic phase shift.