Quasi-particle Interference Effect in the Coulomb Blockade Problem

Abstract

The Coulomb energy in a tunnel junction of very small capacitance, in which there are two or more kinds of quasi-particles, will involve coupling between pairs of quasi-particle species. The variation in the number of one of them will affect the motion of the others. This should be detectable in a current-biased experimental setup. Taking Josephson and single-electron tunnelling as an example, we calculate the Fourier coefficients of the voltage across the junction, which is a periodic function of time. We show that the interference effect is significant in that the frequency dependence of the Fourier coefficients is completely different from that associated with tunnelling of a single species.