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

TL;DR

This paper investigates how ac magnetic fluxes can induce charge pumping in mesoscopic rings, examining the conditions for dc current generation and the breakdown of Onsager symmetry under various configurations.

Contribution

It introduces a detailed analysis of charge pumping mechanisms using ac magnetic fluxes and explores the dynamical breakdown of Onsager symmetry in mesoscopic systems.

Findings

Pumped dc current can be generated in the adiabatic regime.

Onsager-Casimir relations can be broken under certain ac flux configurations.

Symmetry properties depend on static flux components and bias conditions.

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.