ATOM INTERFEROMETRY IN A STATIC ELECTRIC-FIELD - MEASUREMENT OF THE AHARONOV-CASHER PHASE

Consecutive, phase-coherent, near-resonant optical excitations of atom s have been used to realize an atom interferometer with a beam of ther mal calcium atoms. We have measured the topological phase shift due to the interaction of a static electric field with the magnetic dipole m oment of a moving atom (Aharonov-Casher effect). The observed phase sh ift was proportional to the electric field and, within our experimenta l uncertainty, independent of the particle's velocity. The measured va lue of the phase shift has been found to agree with the predicted one within a relative uncertainty of 2.2%.