  We study how dephasing affects the distribution of the dc current pumped
through a chaotic quantum dot. We introduce dephasing by the addition of a
voltage probe to the quantum dot, treating both the case of controlled
dephasing (when the voltage probe is coupled to the dot via a ballistic point
contact with a conductance that is increased stepwise) and intrinsic dephasing
(for which the voltage probe serves as a phenomelogical model). While dephasing
eventually suppresses the dc current through the dot, we also find that, for a
quantum dot with single-mode point contacts, a small amount of dephasing
actually decreases the likelihood of a zero pumped current.
