https://doi.org/10.1140/epjs/s11734-023-01000-6
Regular Article
About the performance of perturbative treatments of the spin-boson dynamics within the hierarchical equations of motion approach
Institute for Complex Quantum Systems and IQST, Ulm University, Albert-Einstein-Allee 11, 89069, Ulm, Germany
a
meng.xu@uni-ulm.de
b
joachim.ankerhold@uni-ulm.de
Received:
26
June
2023
Accepted:
3
October
2023
Published online:
11
October
2023
The hierarchical equations of motion (HEOM) provide a numerically exact approach for simulating the dynamics of open quantum systems coupled to a harmonic bath. However, its applicability has traditionally been limited to specific spectral forms and relatively high temperatures. Recently, an extended version called Free-Pole HEOM (FP-HEOM) has been developed to overcome these limitations. In this study, we demonstrate that the FP-HEOM method can be systematically employed to investigate higher order master equations by truncating the FP-HEOM hierarchy at a desired tier. We focus on the challenging scenario of the spin-boson problem with a sub-Ohmic spectral distribution at zero temperature and analyze the performance of the corresponding master equations. Furthermore, we compare the memory kernel for population dynamics obtained from the exact FP-HEOM dynamics with that of the approximate Non-Interacting-Blip Approximation (NIBA).
© The Author(s) 2023
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