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

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.

Automated summary

The hierarchical equations of motion approach allows for numerically exact simulation of nonequilibrium transport in general open quantum systems involving multiple macroscopic environments. The method's performance has been demonstrated in a nanosystem model, showing intricate interplay between electronic and vibrational degrees of freedom in transport processes. Discussions on the use of importance criteria to improve efficiency have also been included.