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Autori principali: Calvo-Fernández, Aitor, Blanco-Rey, María, Eiguren, Asier
Natura: Preprint
Pubblicazione: 2024
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Accesso online:https://arxiv.org/abs/2409.12050
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author Calvo-Fernández, Aitor
Blanco-Rey, María
Eiguren, Asier
author_facet Calvo-Fernández, Aitor
Blanco-Rey, María
Eiguren, Asier
contents Exploiting symmetries in the numerical renormalization group (NRG) method significantly enhances performance by improving accuracy, increasing computational speed, and optimizing memory efficiency. Published codes focus on continuous rotations and unitary groups, which generally are not applicable to systems with strong crystal-field effects. The PointGroupNRG code implements symmetries related to discrete rotation groups, which are defined by the user in terms of Clebsch-Gordan coefficients, together with particle conservation and spin rotation symmetries. In this paper we present a new version of the code that extends the available finite groups, previously limited to simply reducible point groups, in a way that all point and double groups become accessible. It also includes the full spin-orbital rotation group. Moreover, to improve the code's flexibility for impurities with complex interactions, this new version allows to choose between a standard Anderson Hamiltonian for the impurity or, as another novel feature, an ionic model that requires only the spectrum and the impurity Lehmann amplitudes.
format Preprint
id arxiv_https___arxiv_org_abs_2409_12050
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Numerical renormalization group calculations for magnetic impurity systems with spin-orbit coupling and crystal-field effects
Calvo-Fernández, Aitor
Blanco-Rey, María
Eiguren, Asier
Strongly Correlated Electrons
Exploiting symmetries in the numerical renormalization group (NRG) method significantly enhances performance by improving accuracy, increasing computational speed, and optimizing memory efficiency. Published codes focus on continuous rotations and unitary groups, which generally are not applicable to systems with strong crystal-field effects. The PointGroupNRG code implements symmetries related to discrete rotation groups, which are defined by the user in terms of Clebsch-Gordan coefficients, together with particle conservation and spin rotation symmetries. In this paper we present a new version of the code that extends the available finite groups, previously limited to simply reducible point groups, in a way that all point and double groups become accessible. It also includes the full spin-orbital rotation group. Moreover, to improve the code's flexibility for impurities with complex interactions, this new version allows to choose between a standard Anderson Hamiltonian for the impurity or, as another novel feature, an ionic model that requires only the spectrum and the impurity Lehmann amplitudes.
title Numerical renormalization group calculations for magnetic impurity systems with spin-orbit coupling and crystal-field effects
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2409.12050