Nonequilibrium open quantum systems with multiple bosonic and fermionic environments: A hierarchical equations of motion approach

TL;DR

This paper introduces a hierarchical equations of motion method for accurately simulating nonequilibrium transport in complex open quantum systems with multiple bosonic and fermionic environments, capturing intricate interactions.

Contribution

The paper develops a numerically exact hierarchical equations of motion approach for open quantum systems with multiple environments, enhancing simulation capabilities for complex nonequilibrium scenarios.

Findings

Demonstrates the method on a nanosystem with electronic and vibrational interactions.

Reveals the interplay of electronic and vibrational effects in transport.

Discusses efficiency improvements using importance criteria.

Abstract

We present a hierarchical equations of motion approach, which allows a numerically exact simulation of nonequilibrium transport in general open quantum systems involving multiple macroscopic bosonic and fermionic environments. The performance of the method is demonstrated for a model of a nanosystem, which involves interacting electronic and vibrational degrees of freedom and is coupled to fermionic and bosonic baths. The results show the intricate interplay of electronic and vibrational degrees of freedom in this nonequilibrium transport scenario for both voltage and thermally driven transport processes. Furthermore, the use of importance criteria to improve the efficiency of the method is discussed.