Coulomb induced positive current-current correlations in normal conductors

TL;DR

This paper demonstrates that Coulomb interactions can induce positive current-current correlations in mesoscopic conductors, contrasting the usual negative correlations due to quantum antisymmetry, with implications for understanding charge fluctuations.

Contribution

It reveals that Coulomb interactions can lead to positive current correlations in mesoscopic conductors, extending the understanding beyond wave-function antisymmetry effects.

Findings

Coulomb interactions induce positive current correlations.

Charge fluctuations extend wave-functions near contacts.

Analysis of quantum point contact in high magnetic field.

Abstract

In the white-noise limit current correlations measured at different contacts of a mesoscopic conductor are negative due to the antisymmetry of the wave function (Pauli principle). We show that current fluctuations at capacitive contacts induced via the long range Coulomb interaction as consequence of charge fluctuations in the mesoscopic sample can be {\it positively} correlated. The positive correlations are a consequence of the extension of the wave-functions into areas near both contacts. As an example we investigate in detail a quantum point contact in a high magnetic field under conditions in which transport is along an edge state.