  We argue that all anomalous transport properties of coherent quantum quantum
Hall bilayers can be understood in terms of a mean-field transport theory in
which the condensate phase is nearly uniform across the sample, and the
strength of condensate coupling to interlayer tunneling processes is
substantially reduced compared to the predictions of disorder-free microscopic
mean-field theory. These ingredients provide a natural explanation for recently
established I-V characteristics which feature a critical current above which
the tunneling resistance abruptly increases and a non-local interaction between
interlayer tunneling at the inner and outer edges of Corbino rings. We propose
a microscopic picture in which disorder is the main agent responsible for the
reduction of the effective interlayer tunneling strength.
