Improved master equation approach to quantum transport: From Born to self-consistent Born approximation

TL;DR

This paper introduces an improved master equation approach for quantum transport using a self-consistent Born approximation, enhancing accuracy and ability to predict complex phenomena like the Kondo effect.

Contribution

It develops a self-consistent Born approximation method that replaces the free Green's function with an effective propagator, improving quantum transport modeling.

Findings

Recovers exact noninteracting transport results at arbitrary voltages.

Successfully predicts the nonequilibrium Kondo effect.

Demonstrates improved accuracy and convenience of the scheme.

Abstract

Beyond the second-order Born approximation, we develop an improved master equation approach to quantum transport by virtue of a self-consistent Born approximation. The basic idea is replacing the free Green's function in the tunneling self-energy by an effective reduced propagator under the Born approximation. We found that the effect of this simple improvement is remarkable, for instance, it can not only recover the exact result of noninteracting transport under arbitrary voltages, but also predict the challenging nonequilibrium Kondo effect. In addition to having an elegant structure, the application convenience and accuracy of the proposed scheme, as demonstrated by the examples in this work, may suggest it a useful tool for quantum transports.