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Main Authors: Holtkamp, Yannick Marcel, Godinez-Ramirez, Emiliano, Kleinekathöfer, Ulrich
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2410.04294
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author Holtkamp, Yannick Marcel
Godinez-Ramirez, Emiliano
Kleinekathöfer, Ulrich
author_facet Holtkamp, Yannick Marcel
Godinez-Ramirez, Emiliano
Kleinekathöfer, Ulrich
contents Although recent advances in simulating open quantum systems have lead to significant progress, the applicability of numerically exact methods is still restricted to rather small systems. Hence, more approximate methods remain relevant due to their computational efficiency, enabling simulations of larger systems over extended timescales. In this study, we present advances for one such method, namely the Numerical Integration of Schrödinger Equation (NISE). Firstly, we introduce a modified ensemble-averaging procedure that improves the long-time behavior of the thermalized variant of the NISE scheme, termed Thermalized NISE. Secondly, we demonstrate how to use the NISE in conjunction with (highly) structured spectral densities by utilizing a noise generating algorithm for arbitrary structured noise. This algorithm also serves as a tool for establishing best practices in determining spectral densities from excited state calculations along molecular dynamics or quantum mechanics/molecular mechanics trajectories. Finally, we assess the ability of the NISE approach to calculate absorption spectra and demonstrate the utility of the proposed modifications by determining population dynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2410_04294
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Spectral Densities, Structured Noise and Ensemble Averaging within Open Quantum Dynamics
Holtkamp, Yannick Marcel
Godinez-Ramirez, Emiliano
Kleinekathöfer, Ulrich
Quantum Physics
Machine Learning
Chemical Physics
Computational Physics
Although recent advances in simulating open quantum systems have lead to significant progress, the applicability of numerically exact methods is still restricted to rather small systems. Hence, more approximate methods remain relevant due to their computational efficiency, enabling simulations of larger systems over extended timescales. In this study, we present advances for one such method, namely the Numerical Integration of Schrödinger Equation (NISE). Firstly, we introduce a modified ensemble-averaging procedure that improves the long-time behavior of the thermalized variant of the NISE scheme, termed Thermalized NISE. Secondly, we demonstrate how to use the NISE in conjunction with (highly) structured spectral densities by utilizing a noise generating algorithm for arbitrary structured noise. This algorithm also serves as a tool for establishing best practices in determining spectral densities from excited state calculations along molecular dynamics or quantum mechanics/molecular mechanics trajectories. Finally, we assess the ability of the NISE approach to calculate absorption spectra and demonstrate the utility of the proposed modifications by determining population dynamics.
title Spectral Densities, Structured Noise and Ensemble Averaging within Open Quantum Dynamics
topic Quantum Physics
Machine Learning
Chemical Physics
Computational Physics
url https://arxiv.org/abs/2410.04294