Rectification of displacement currents in an adiabatic electron pump

Rectification of ac displacement currents generated by periodic variation of two independent gate voltages of a quantum dot can lead to a de voltage linear in the frequency omega. The presence of this rectified displacement current could account for the magnetic field symmetry observed in a recent measurement on an adiabatic quantum electron pump by Switkes et al. [Science 283, 1905 (1999)].