Weak localization in a system with a barrier: Dephasing and weak Coulomb blockade

TL;DR

This paper investigates how electron-electron interactions cause dephasing in weak localization within short metallic conductors with barriers, explaining low-temperature decoherence saturation observed in quantum dots.

Contribution

It provides a non-perturbative analysis showing that interactions induce persistent dephasing, reducing weak localization effects even at zero temperature.

Findings

Electron-electron interactions cause dephasing at T=0.

Dephasing suppresses weak localization correction.

Results explain low-temperature decoherence saturation in quantum dots.

Abstract

We non-perturbatively analyze the effect of electron-electron interactions on weak localization (WL) in relatively short metallic conductors with a tunnel barrier. We demonstrate that the main effect of interactions is electron dephasing which persists down to T=0 and yields suppression of WL correction to conductance below its non-interacting value. Our results may account for recent observations of low temperature saturation of the electron decoherence time in quantum dots.