Spectral Densities, Structured Noise and Ensemble Averaging within Open Quantum Dynamics
Abstract
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 Schr\"odinger 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.
Cite
@article{arxiv.2410.04294,
title = {Spectral Densities, Structured Noise and Ensemble Averaging within Open Quantum Dynamics},
author = {Yannick Marcel Holtkamp and Emiliano Godinez-Ramirez and Ulrich Kleinekathöfer},
journal= {arXiv preprint arXiv:2410.04294},
year = {2024}
}
Comments
48 pages, 13 figures. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in J. Chem. Phys. 161, 134101 (2024) and may be found at https://doi.org/10.1063/5.0224807