Transport theory of coupled quantum dots based on auxiliary operator method

TL;DR

This paper develops a comprehensive transport theory for coupled quantum dots using an extended auxiliary operator method, deriving exact expressions for key physical quantities under non-equilibrium conditions.

Contribution

It introduces a generalized auxiliary operator framework that incorporates finite Coulomb repulsion, extending previous non-crossing approximation approaches.

Findings

Derived exact formulas for currents, occupation numbers, and spin correlations.

Extended the NCA method to handle full occupation numbers with finite Coulomb interaction.

Provided a theoretical basis for analyzing electron transport in coupled quantum dots.

Abstract

We formulate the theory of electron transport through coupled-quantum dots by extending the auxiliary operator representation. By using the generating functional technique, we derive the exact expressions for currents, dot-occupation numbers and spin correlations, and examine them based on the non-equilibrium Green's function method under the non-crossing approximation (NCA). Our formulation generalizes the previous NCA approaches by allowing full occupation numbers with a finite Coulomb repulsion.