  We present exact results on the non-equilibrium current fluctuations for 2
quantum dots in series throughout a crossover from non-Fermi liquid to Fermi
liquid behavior described by the 2 impurity Kondo model. The result corresponds
to resonant tunneling of carriers of charge $2e$ for a critical inter-impurity
coupling. At low energy scales, the result can be understood from a Fermi
liquid approach that we develop and use to also study non-equilibrium transport
in an alternative double dot realization of the 2 impurity Kondo model under
current experimental study.
