Josephson Current Flowing in Cyclically Coupled
Bose-Einstein Condensates

抄録

The Josephson effect in cyclically coupled Bose-Einstein condensates is studied theoretically. We analyze the simultaneous Gross-Pitaevskii equations with coupling terms between adjacent condensates. Depending on the initial relative phases between condensates, Josephson current flows cyclically to create a quantized vortex. Reducing the coupling between condensates changes the motion from periodic to chaotic, thus suppressing the cyclic current. The relation to the Kibble-Zurek mechanism is discussed; the density of the generated vortices is less than that predicted by this mechanism.