Control of atomic currents using a quantum stirring device

We propose a BEC stirring device which can be regarded as the incorporation of a quantum pump into a closed circuit. It produces a DC circulating atomic current in response to a cyclic adiabatic change of the on-site potentials and the tunneling rates between adjunct sites of an optical trap. We show that the nature of the transport process depends crucially on the sign and on the strength of the interatomic interactions, ranging from a one-by-one transport of atoms (for strong repulsive interaction) to a regime where the particles are are glued together and behave like a huge classical ball that rolls from site to site (for strong attractive interaction). We demonstrate the feasibility of this concept and point out that such device can be utilized in order to probe the interatomic interactions.