Parallel Quantum Circuit in a Tunnel Junction

Spectral analysis of 1 and 2-states per line quantum bus are normally sufficient to determine the effective V(ab)(N) electronic coupling between the emitter and receiver states through the bus as a function of the number N of parallel lines. When V(ab)(N) is difficult to determine, an Heisenberg-Rabi time dependent quantum exchange process must be triggered through the bus to capture the secular oscillation frequency Ω(ab)(N) between those states. Two different linear and [Image: see text] regimes are demonstrated for Ω(ab)(N) as a function of N. When the initial preparation is replaced by coupling of the quantum bus to semi-infinite electrodes, the resulting quantum transduction process is not faithfully following the Ω(ab)(N) variations. Because of the electronic transparency normalisation to unity and of the low pass filter character of this transduction, large Ω(ab)(N) cannot be captured by the tunnel junction. The broadly used concept of electrical contact between a metallic nanopad and a molecular device must be better described as a quantum transduction process. At small coupling and when N is small enough not to compensate for this small coupling, an N(2) power law is preserved for Ω(ab)(N) and for V(ab)(N).