Optical absorption spectra from the GW-Bethe-Salpeter framework for thousands of atoms
Abstract
The frequency-dependent absorption and emission of light determine the colors of matter and underpin today's technologies, from solar cells to light-emitting diodes. Predicting optical properties from first principles remains a computational challenge, especially for large and disordered systems. The GW plus Bethe-Salpeter equation (GW-BSE) approach provides predictive accuracy for optical properties, but conventional implementations become costly as system size grows. Here, we present a GW-BSE framework combining real-time propagation, atom-centered basis sets, and a locally optimized real-space resolution of the identity. The cost of each propagation step scales quadratically with system size and roughly equals the cost of one self-consistent-field iteration in a density-functional calculation with a semilocal functional. This computational efficiency allows us to calculate the absorption spectrum of a nanographene containing 4616 atoms and opens a path toward routine calculations of optical properties for large disordered systems.
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BibTeX
@misc{graml2026optical,
title = {{Optical absorption spectra from the $GW$-Bethe-Salpeter framework for thousands of atoms}},
author = {Maximilian Graml and Ritaj Tyagi and Rémi Pasquier and Štěpán Marek and Jan Wilhelm},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.11767},
eprint = {2610.11767},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.11767},
}
RIS
TY - UNPB
TI - Optical absorption spectra from the GW-Bethe-Salpeter framework for thousands of atoms
AU - Maximilian Graml
AU - Ritaj Tyagi
AU - Rémi Pasquier
AU - Štěpán Marek
AU - Jan Wilhelm
PY - 2026
DA - 2026/10/08
PB - arXiv
DO - 10.48550/arxiv.2610.11767
UR - https://arxiv.org/abs/2610.11767
AB - The frequency-dependent absorption and emission of light determine the colors of matter and underpin today's technologies, from solar cells to light-emitting diodes. Predicting optical properties from first principles remains a computational challenge, especially for large and disordered systems. The GW plus Bethe-Salpeter equation (GW-BSE) approach provides predictive accuracy for optical properties, but conventional implementations become costly as system size grows. Here, we present a GW-BSE framework combining real-time propagation, atom-centered basis sets, and a locally optimized real-space resolution of the identity. The cost of each propagation step scales quadratically with system size and roughly equals the cost of one self-consistent-field iteration in a density-functional calculation with a semilocal functional. This computational efficiency allows us to calculate the absorption spectrum of a nanographene containing 4616 atoms and opens a path toward routine calculations of optical properties for large disordered systems.
ER -