Electron transport and current fluctuations in short coherent conductors

TL;DR

This paper investigates how electron-electron interactions influence transport and noise in short coherent conductors, revealing that Coulomb interactions can suppress current but enhance shot noise, especially in highly transparent channels.

Contribution

It introduces a real-time effective action formalism to analyze the interplay of interactions and fluctuations in mesoscopic conductors, highlighting the enhancement of shot noise due to Coulomb effects.

Findings

Coulomb interactions suppress average electron transport.

Coulomb interactions can strongly enhance shot noise.

Frequency dispersion of higher current cumulants is analyzed.

Abstract

Employing a real time effective action formalism we analyze electron transport and current fluctuations in comparatively short coherent conductors in the presence of electron-electron interactions. We demonstrate that, while Coulomb interaction tends to suppress electron transport, it may {\it strongly enhance} shot noise in scatterers with highly transparent conducting channels. This effect of excess noise is governed by the Coulomb gap observed in the current-voltage characteristics of such scatterers. We also analyze the frequency dispersion of higher current cumulants and emphasize a direct relation between electron-electron interaction effects and current fluctuations in disordered mesoscopic conductors.