  We show that quantum pumping does not always require a quantum description or
a quantum phase. Quantum pumping is shown to encompass different types of
processes, some of which intrinsically rely on phase while others do not. We
also show that many pumping processes have a hidden antisymmetric component
that contributes significantly to the instantaneous current at the terminals
without causing net charge transfer in a period. We have also computed the
exact pumped current for some cases over a full range of time variation from
adiabatic to non-adiabatic.
