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Main Authors: Ma, Chenlin, Zheng, Fulu, Sun, Kewei, Wang, Lu, Zhao, Yang
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2510.09029
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author Ma, Chenlin
Zheng, Fulu
Sun, Kewei
Wang, Lu
Zhao, Yang
author_facet Ma, Chenlin
Zheng, Fulu
Sun, Kewei
Wang, Lu
Zhao, Yang
contents We perform benchmark simulations using the time-dependent variational approach with the multiple Davydov Ansatz (mDA) to study realtime nonequilibrium dynamics in a single qubit model coupled to two thermal baths with distinct temperatures. A broad region of the parameter space has been investigated, accompanied by a detailed analysis of the convergence behavior of the mDA method. In addition, we have compared our mD2 results to those from two widely adopted, numerically "exact" techniques: the methods of hierarchical equations of motion (HEOM) and the quasi-adiabatic path integral (QUAPI). It is found that the mDA approach in combination with thermal field dynamics yields numerically accurate, convergent results in nearly all regions of the parameter space examined, including those that pose serious challenges for QUAPI and HEOM. Our results reveal that mDA offers a highly adaptable framework capable of capturing long-time dynamics, even in challenging regimes where other methods face limitations. These findings underscore the potential of mDA as a versatile tool for exploring quantum thermodynamics, energy transfer processes, and non-equilibrium quantum systems.
format Preprint
id arxiv_https___arxiv_org_abs_2510_09029
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle A Davydov Ansatz approach to accurate system-bath dynamics in the presence of multiple baths with distinct temperatures
Ma, Chenlin
Zheng, Fulu
Sun, Kewei
Wang, Lu
Zhao, Yang
Quantum Physics
We perform benchmark simulations using the time-dependent variational approach with the multiple Davydov Ansatz (mDA) to study realtime nonequilibrium dynamics in a single qubit model coupled to two thermal baths with distinct temperatures. A broad region of the parameter space has been investigated, accompanied by a detailed analysis of the convergence behavior of the mDA method. In addition, we have compared our mD2 results to those from two widely adopted, numerically "exact" techniques: the methods of hierarchical equations of motion (HEOM) and the quasi-adiabatic path integral (QUAPI). It is found that the mDA approach in combination with thermal field dynamics yields numerically accurate, convergent results in nearly all regions of the parameter space examined, including those that pose serious challenges for QUAPI and HEOM. Our results reveal that mDA offers a highly adaptable framework capable of capturing long-time dynamics, even in challenging regimes where other methods face limitations. These findings underscore the potential of mDA as a versatile tool for exploring quantum thermodynamics, energy transfer processes, and non-equilibrium quantum systems.
title A Davydov Ansatz approach to accurate system-bath dynamics in the presence of multiple baths with distinct temperatures
topic Quantum Physics
url https://arxiv.org/abs/2510.09029