  Single field baryogenesis, a scenario for Dirac leptogenesis sourced by a
time-dependent scalar condensate, is studied. We compare the creation of the
charge asymmetry by the perturbative decay of the condensate with the
nonperturbative decay, a process of particle production commonly known in the
context of inflation as preheating. The nonperturbative channel dominates when
the coupling of the scalar field to leptons is sufficiently large.
