Optimizing excited states in quantum Monte Carlo: A reassessment of double excitations

Fuente: arXiv
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Auteurs principaux: Shepard, Stuart, Scemama, Anthony, Moroni, Saverio, Filippi, Claudia
Format: Preprint
Publié: 2025
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author Shepard, Stuart
Scemama, Anthony
Moroni, Saverio
Filippi, Claudia
author_facet Shepard, Stuart
Scemama, Anthony
Moroni, Saverio
Filippi, Claudia
contents Quantum Monte Carlo (QMC) methods have proven to be highly accurate for computing excited states, but the choice of optimization strategies for multiple states remains an active topic of investigation. In this work, we revisit the calculation of double excitation energies in nitroxyl, glyoxal, tetrazine, and cyclopentadienone, exploring different objective functionals and their impact on the accuracy and robustness of QMC. A previous study for these systems employed a penalty functional to enforce orthogonality among the states, but the chosen prefactors did not strictly ensure convergence to the target states. Here, we confirm the reliability of previous results by comparing excitation energies obtained with different functionals and analyzing their consistency. Additionally, we investigate the performance of different functionals when starting from a pre-collapsed excited state, providing insight into their ability to recover the target wave functions.
format Preprint
id arxiv_https___arxiv_org_abs_2504_09259
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Optimizing excited states in quantum Monte Carlo: A reassessment of double excitations
Shepard, Stuart
Scemama, Anthony
Moroni, Saverio
Filippi, Claudia
Computational Physics
Chemical Physics
Quantum Monte Carlo (QMC) methods have proven to be highly accurate for computing excited states, but the choice of optimization strategies for multiple states remains an active topic of investigation. In this work, we revisit the calculation of double excitation energies in nitroxyl, glyoxal, tetrazine, and cyclopentadienone, exploring different objective functionals and their impact on the accuracy and robustness of QMC. A previous study for these systems employed a penalty functional to enforce orthogonality among the states, but the chosen prefactors did not strictly ensure convergence to the target states. Here, we confirm the reliability of previous results by comparing excitation energies obtained with different functionals and analyzing their consistency. Additionally, we investigate the performance of different functionals when starting from a pre-collapsed excited state, providing insight into their ability to recover the target wave functions.
title Optimizing excited states in quantum Monte Carlo: A reassessment of double excitations
topic Computational Physics
Chemical Physics
url https://arxiv.org/abs/2504.09259