Nonperturbative analysis of coupled quantum dots in a phonon bath

TL;DR

This paper applies a nonperturbative real-time renormalization-group method to analyze electron transport in coupled quantum dots interacting with a phonon bath, accurately modeling experimental results including wavefunction effects.

Contribution

It introduces a nonperturbative approach to study coupled quantum dots in a phonon environment, capturing full electron-phonon interactions beyond previous perturbative methods.

Findings

Quantitative agreement with experimental tunnel current data.

Derived dependence of wavefunction extension on energy difference.

Validated method for arbitrary parameters with moderate couplings.

Abstract

Transport through coupled quantum dots in a phonon bath is studied using the recently developed real-time renormalization-group method. Thereby, the problem can be treated beyond perturbation theory regarding the complete interaction. A reliable solution for the stationary tunnel current is obtained for the case of moderately strong couplings of the dots to the leads and to the phonon bath. Any other parameter is arbitrary, and the complete electron-phonon interaction is taken into account. Experimental results are quantitatively reproduced by taking into account a finite extension of the wavefunctions within the dots. Its dependence on the energy difference between the dots is derived.