On the Discretization Error of the Discrete Generalized Quantum Master Equation

Fuente: arXiv
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Main Authors: Peng, Ruojing, Lindoy, Lachlan P., Lee, Joonho
Format: Preprint
Published: 2025
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author Peng, Ruojing
Lindoy, Lachlan P.
Lee, Joonho
author_facet Peng, Ruojing
Lindoy, Lachlan P.
Lee, Joonho
contents The transfer tensor method (TTM) [Cerrillo and Cao, Phys. Rev. Lett. 2014, 112, 110401] can be considered a discrete-time formulation of the Nakajima-Zwanzig quantum master equation (NZ-QME) for modeling non-Markovian quantum dynamics. A recent paper [Makri, J. Chem. Theory Comput. 2025, 21, 5037] raised concerns regarding the consistency of the TTM discretization, particularly a spurious term at the initial time \( t=0 \). This Communication presents a detailed analysis of the discretization structure of TTM, clarifying the origin of the initial-time correction and establishing a consistent relationship between the TTM discrete-time memory kernel \( K_N \), and the continuous-time NZ-QME kernel \( \mathcal{K}(NΔt) \). This relationship is validated numerically using the spin-boson model, demonstrating convergence of reconstructed memory kernels and accurate dynamical evolution as \( Δt \to 0 \). While TTM provides a consistent discretization, we note that alternative schemes are also viable, such as the midpoint derivative/midpoint integral scheme proposed in Makri's work. The relative performance of various schemes for either computing accurate \( \mathcal{K}(NΔt) \) from exact dynamics, or obtaining accurate dynamics from exact \( \mathcal{K}(NΔt) \), warrants further investigation.
format Preprint
id arxiv_https___arxiv_org_abs_2507_19323
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On the Discretization Error of the Discrete Generalized Quantum Master Equation
Peng, Ruojing
Lindoy, Lachlan P.
Lee, Joonho
Quantum Physics
Chemical Physics
The transfer tensor method (TTM) [Cerrillo and Cao, Phys. Rev. Lett. 2014, 112, 110401] can be considered a discrete-time formulation of the Nakajima-Zwanzig quantum master equation (NZ-QME) for modeling non-Markovian quantum dynamics. A recent paper [Makri, J. Chem. Theory Comput. 2025, 21, 5037] raised concerns regarding the consistency of the TTM discretization, particularly a spurious term at the initial time \( t=0 \). This Communication presents a detailed analysis of the discretization structure of TTM, clarifying the origin of the initial-time correction and establishing a consistent relationship between the TTM discrete-time memory kernel \( K_N \), and the continuous-time NZ-QME kernel \( \mathcal{K}(NΔt) \). This relationship is validated numerically using the spin-boson model, demonstrating convergence of reconstructed memory kernels and accurate dynamical evolution as \( Δt \to 0 \). While TTM provides a consistent discretization, we note that alternative schemes are also viable, such as the midpoint derivative/midpoint integral scheme proposed in Makri's work. The relative performance of various schemes for either computing accurate \( \mathcal{K}(NΔt) \) from exact dynamics, or obtaining accurate dynamics from exact \( \mathcal{K}(NΔt) \), warrants further investigation.
title On the Discretization Error of the Discrete Generalized Quantum Master Equation
topic Quantum Physics
Chemical Physics
url https://arxiv.org/abs/2507.19323