  Using exact-diagonalization of small clusters and Dyson equation embedding
techniques, the conductance $G$ of linear arrays of quantum dots is
investigated. The Hubbard interaction induces Kondo peaks at low temperatures
for an odd number of dots. Remarkably, the Kondo peak is split in half by a
deep minimum, and the conductance vanishes at one value of the gate voltage.
Tentative explanations for this unusual effect are proposed, including an
interference process between two channels contributing to $G$, with one more
and one less particle than the exactly-solved cluster ground-state. The Hubbard
interaction and fermionic statistics of electrons also appear to be important
to understand this phenomenon. Although most of the calculations used a
particle-hole symmetric Hamiltonian and formalism, results also presented here
show that the conductance dip exists even when this symmetry is broken. The
conductance cancellation effect obtained using numerical techniques is
potentially interesting, and other many-body techniques should be used to
confirm its existence.
