Electron-electron interaction effects in quantum point contacts

TL;DR

This paper investigates how electron-electron interactions influence conductance, shot noise, and thermopower in quantum point contacts, providing theoretical insights consistent with the experimentally observed 0.7 anomaly.

Contribution

It introduces a comprehensive perturbative analysis of interaction effects, including all non momentum-conserving processes, and computes temperature-dependent conductance.

Findings

Conductance approaches ~ e^2/h at higher temperatures

Results align with experimental 0.7 anomaly observations

Provides a self-consistent second-order perturbation framework

Abstract

We consider interaction effects in quantum point contacts on the first quantization plateau, taking into account all non momentum-conserving processes. We compute low-temperature linear and non-linear conductance, shot noise, and thermopower by perturbation theory, and show that they are consistent with experimental observations on the so-called "0.7 anomaly". The full temperature-dependent conductance is obtained from self-consistent second-order perturbation theory and approaches ~ e^2/h at higher temperatures, but still smaller than the Fermi temperature.