Antiferromagnetic and spin spiral correlations in the doped two-dimensional Hubbard model: gauge symmetry, Ward identities, and dynamical mean-field theory analysis

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Main Authors: Goremykin, I. A., Katanin, A. A.
Format: Preprint
Published: 2024
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author Goremykin, I. A.
Katanin, A. A.
author_facet Goremykin, I. A.
Katanin, A. A.
contents We reconsider the derivation of Ward identities for spin stiffnesses, which determine the non-linear sigma model of magnetic degrees of freedom of interacting electrons in the presence of antiferromagnetic or incommensurate correlations. We emphasize that in the approaches, which do not break explicitly spin symmetry of the action, the spatial components of gauge kernel, which is used to obtain spin stiffnesses, remain gauge invariant even in case of spontaneous spin symmetry breaking. We derive the corrected Ward identities, which account for this gauge invariance. We emphasize that the frequency dependence of temporal spin stiffnesses is not fixed by the obtained identities, and show that the infinitesimally small external staggered field is crucially important to obtain finite static uniform transverse susceptibility. On the other hand, we find that the spatial spin stiffnesses are determined by the gauge kernel of the Legendre transformed theory, which is in general {\it different} from the gauge kernel of the original theory and obtain an explicit expressions for spatial spin stiffnesses through susceptibilities and current correlation functions. We verify numerically the obtained results within dynamic mean field theory, and obtain doping dependencies of the resulting spin stiffnesses for antiferromagnetic and incommensurate phase.
format Preprint
id arxiv_https___arxiv_org_abs_2405_04277
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Antiferromagnetic and spin spiral correlations in the doped two-dimensional Hubbard model: gauge symmetry, Ward identities, and dynamical mean-field theory analysis
Goremykin, I. A.
Katanin, A. A.
Strongly Correlated Electrons
We reconsider the derivation of Ward identities for spin stiffnesses, which determine the non-linear sigma model of magnetic degrees of freedom of interacting electrons in the presence of antiferromagnetic or incommensurate correlations. We emphasize that in the approaches, which do not break explicitly spin symmetry of the action, the spatial components of gauge kernel, which is used to obtain spin stiffnesses, remain gauge invariant even in case of spontaneous spin symmetry breaking. We derive the corrected Ward identities, which account for this gauge invariance. We emphasize that the frequency dependence of temporal spin stiffnesses is not fixed by the obtained identities, and show that the infinitesimally small external staggered field is crucially important to obtain finite static uniform transverse susceptibility. On the other hand, we find that the spatial spin stiffnesses are determined by the gauge kernel of the Legendre transformed theory, which is in general {\it different} from the gauge kernel of the original theory and obtain an explicit expressions for spatial spin stiffnesses through susceptibilities and current correlation functions. We verify numerically the obtained results within dynamic mean field theory, and obtain doping dependencies of the resulting spin stiffnesses for antiferromagnetic and incommensurate phase.
title Antiferromagnetic and spin spiral correlations in the doped two-dimensional Hubbard model: gauge symmetry, Ward identities, and dynamical mean-field theory analysis
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2405.04277