Pumped current and voltage for an adiabatic quantum pump

We consider adiabatic pumping of electrons through a quantum dot. There are two ways to operate the pump: to create a dc current Ī \=I or to create a dc voltage V̄. We demonstrate that, for very slow pumping, Ī \=I and V̄ are not simply related via the dc conductance G as Ī \=I=V̄G. For the case of a chaotic quantum dot, we consider the statistical distribution of V̄G- Ī \=I. Results are presented for the limiting cases of a dot with single-channel and with multichannel point contacts.