Quasi-Lindblad pseudomode theory for open quantum systems

Fuente: arXiv
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Hauptverfasser: Park, Gunhee, Huang, Zhen, Zhu, Yuanran, Yang, Chao, Chan, Garnet Kin-Lic, Lin, Lin
Format: Preprint
Veröffentlicht: 2024
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author Park, Gunhee
Huang, Zhen
Zhu, Yuanran
Yang, Chao
Chan, Garnet Kin-Lic
Lin, Lin
author_facet Park, Gunhee
Huang, Zhen
Zhu, Yuanran
Yang, Chao
Chan, Garnet Kin-Lic
Lin, Lin
contents We introduce a new framework to study the dynamics of open quantum systems with linearly coupled Gaussian baths. Our approach replaces the continuous bath with an auxiliary discrete set of pseudomodes with dissipative dynamics, but we further relax the complete positivity requirement in the Lindblad master equation and formulate a quasi-Lindblad pseudomode theory. We show that this quasi-Lindblad pseudomode formulation directly leads to a representation of the bath correlation function in terms of a complex weighted sum of complex exponentials, an expansion that is known to be rapidly convergent in practice and thus leads to a compact set of pseudomodes. The pseudomode representation is not unique and can differ by a gauge choice. When the global dynamics can be simulated exactly, the system dynamics is unique and independent of the specific pseudomode representation. However, the gauge choice may affect the stability of the global dynamics, and we provide an analysis of why and when the global dynamics can retain stability despite losing positivity. We showcase the performance of this formulation across various spectral densities in both bosonic and fermionic problems, finding significant improvements over conventional pseudomode formulations.
format Preprint
id arxiv_https___arxiv_org_abs_2408_15529
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Quasi-Lindblad pseudomode theory for open quantum systems
Park, Gunhee
Huang, Zhen
Zhu, Yuanran
Yang, Chao
Chan, Garnet Kin-Lic
Lin, Lin
Quantum Physics
Strongly Correlated Electrons
Chemical Physics
Computational Physics
We introduce a new framework to study the dynamics of open quantum systems with linearly coupled Gaussian baths. Our approach replaces the continuous bath with an auxiliary discrete set of pseudomodes with dissipative dynamics, but we further relax the complete positivity requirement in the Lindblad master equation and formulate a quasi-Lindblad pseudomode theory. We show that this quasi-Lindblad pseudomode formulation directly leads to a representation of the bath correlation function in terms of a complex weighted sum of complex exponentials, an expansion that is known to be rapidly convergent in practice and thus leads to a compact set of pseudomodes. The pseudomode representation is not unique and can differ by a gauge choice. When the global dynamics can be simulated exactly, the system dynamics is unique and independent of the specific pseudomode representation. However, the gauge choice may affect the stability of the global dynamics, and we provide an analysis of why and when the global dynamics can retain stability despite losing positivity. We showcase the performance of this formulation across various spectral densities in both bosonic and fermionic problems, finding significant improvements over conventional pseudomode formulations.
title Quasi-Lindblad pseudomode theory for open quantum systems
topic Quantum Physics
Strongly Correlated Electrons
Chemical Physics
Computational Physics
url https://arxiv.org/abs/2408.15529