It has recently been suggested that an Aharonov-Bohm phase should be capable of detection using beams of neutral polarizable particles. A more careful analysis of the proposed experiment suffices to show, however, that it cannot be performed regardless of the strength of the external electric and magnetic fields.
We derive the quantum phase accompanying a neutral particle (with no permanent electric dipole moment) moving in an area where a nonuniform electric field and a uniform magnetic field are simultaneously applied. Such a quantum phase can be ascribed to the sum of the Aharonov-Bohm phases of the charges constituting the neutral particle. An experimental configuration much more practical than a previous suggestion is proposed to test for the phase. The possible nonzero superfluid velocity in the ground state of the 4He condensate is theoretically demonstrated.