A simple improved low temperature correction for the hierarchical equations of motion

Journal Article · 03 August 2022 · Journal of Chemical Physics

DOI: https://doi.org/10.1063/5.0100365 · OSTI ID:1879781

Fay, Thomas P.

The study of open system quantum dynamics has been transformed by the hierarchical equations of motion (HEOM) method, which gives the exact dynamics for a system coupled to a harmonic bath at arbitrary temperature and system–bath coupling strength. However, in its standard form, this method is only consistent with the weak-coupling quantum master equation at all temperatures when many auxiliary density operators are included in the hierarchy, even when low temperature corrections are included. Here, we propose a new low temperature correction scheme for the termination of the hierarchy based on Zwanzig projection, which alleviates this problem and restores consistency with the weak-coupling master equation with a minimal hierarchy. The utility of the new correction scheme is demonstrated on a range of model systems, including the Fenna–Matthews–Olson complex. The new closure is found to improve convergence of the HEOM even beyond the weak-coupling limit and is very straightforward to implement in existing HEOM codes.

• Sponsoring Organization: USDOE
• OSTI ID: 1879781
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 5 Vol. 157; ISSN 0021-9606
• Publisher: American Institute of PhysicsCopyright Statement
• Country of Publication: United States
• Language: English