Fano resonances in the system of coupled point contacts

We examine transport through the system of two coupled quantum point contacts. We show that when one of them is driven close to the pinch-off condition, the conductance of the second one exhibits very pronounced peak. The shape of this peak has a Fano form indicating the formation of the localized state in the quantum point contact near the pinch-off. The experimental data are fitted to the Fano expression with determination of parameters involved. More detailed microscopic analysis demonstrates the existence of both symmetric and antisymmetric contributions to the conductance peak.