Observation of the Aharonov-Casher effect for vortices in Josephson-junction arrays

Abstract

We have observed quantum interference of vortices in a Josephson-junction array. When vortices cross the array along a doubly connected path, the resultant resistance oscillates periodically with an induced charge enclosed by the path. This phenomenon is a manifestation of the Aharonov-Casher effect. The period of oscillation corresponds to the single electron charge due to tunneling of quasiparticles.