  We show that the coherence of charge transfer through a weakly coupled
double-dot dimer can be determined by analyzing the statistics of the
conductance pattern, and does not require large phase coherence length in the
host material. We present an experimental study of the charge transport through
a small Si nanostructure, which contains two quantum dots. The transport
through the dimer is shown to be coherent. At the same time, one of the dots is
strongly coupled to the leads, and the overall transport is dominated by
inelastic co-tunneling processes.
