Pumping charge with ac magnetic fluxes and the dynamical breakdown of Onsager symmetry

Abstract

We study the transport properties of setups with one and two mesoscopic rings threaded by ac magnetic fluxes of the form \Phi(t)=\Phi^{dc} + \Phi^{ac} cos(\Omega_0 t + \delta) and connected to two different particle reservoirs. We analyze the conditions to generate a pumped dc current in the adiabatic regime. We also study the symmetry properties of the induced dc current as a function of the static component of the flux, \Phi^{dc}, with and without a dc bias voltage applied at the reservoirs. We analyze, in particular, the validity of the Onsager-Casimir relations for different configurations of the setups.