Aharonov-Casher effect for particles of arbitrary spin

The Aharonov-Casher (AC) effect for the quantum motion of a neutral magnetized particle in an electric field is believed to be a topological effect closely related to the well-known Aharonov-Bohm (AB) effect. We study its dependence on the spin of the particle involved. Duality of the AB and AC effects is demonstrated to exist only for two extreme spin (and magnetic-moment) projections. A classical consideration confirms this conclusion. The motion of a classical magnetized particle with generally oriented magnetic moment in the AC field appears to be subjected to both forces and torques. Only for two special orientations of the magnetic moment (same as in the quantum case) is the motion in question effectively free and similar to the AB motion of a charged particle. Thus, the AC effect is not really topological. The presence of higher multipoles totally destroys possible AB-AC duality.