Quark propagator with complex-valued momentum from Schwinger-Dyson equation in the Euclidean space

Fuente: arXiv
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Auteurs principaux: Jia, Shaoyang, Cloët, Ian
Format: Preprint
Publié: 2024
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author Jia, Shaoyang
Cloët, Ian
author_facet Jia, Shaoyang
Cloët, Ian
contents In the Euclidean-space formulation of integral equations for the structure of quantum chromodynamics (QCD) bound states, the quark propagators with complex-valued momentum are densely sampled. We therefore propose an accurate and efficient algorithm to compute these propagators. The quark propagator both on the spacelike real axis and at complex-valued momenta is determined from its Schwinger-Dyson equation (SDE). We first apply an iterative solver to determine the quark propagator on the spacelike real axis. The propagator at complex-valued momenta is then computed from its self-energy based on this solution, where demanding integrals are encountered. In order to compute of these integrals, we apply customized variable transformations for the radial integral after subtracting the asymptotics. We subsequently apply an optional compound of quadrature rules for the angular integral. The contribution from the asymptotics is added at the last step. The accuracy and the performance of this algorithm for the quark propagator at complex-valued momentum are tested in comparison with an adaptive quadrature.
format Preprint
id arxiv_https___arxiv_org_abs_2401_11019
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Quark propagator with complex-valued momentum from Schwinger-Dyson equation in the Euclidean space
Jia, Shaoyang
Cloët, Ian
Nuclear Theory
High Energy Physics - Theory
In the Euclidean-space formulation of integral equations for the structure of quantum chromodynamics (QCD) bound states, the quark propagators with complex-valued momentum are densely sampled. We therefore propose an accurate and efficient algorithm to compute these propagators. The quark propagator both on the spacelike real axis and at complex-valued momenta is determined from its Schwinger-Dyson equation (SDE). We first apply an iterative solver to determine the quark propagator on the spacelike real axis. The propagator at complex-valued momenta is then computed from its self-energy based on this solution, where demanding integrals are encountered. In order to compute of these integrals, we apply customized variable transformations for the radial integral after subtracting the asymptotics. We subsequently apply an optional compound of quadrature rules for the angular integral. The contribution from the asymptotics is added at the last step. The accuracy and the performance of this algorithm for the quark propagator at complex-valued momentum are tested in comparison with an adaptive quadrature.
title Quark propagator with complex-valued momentum from Schwinger-Dyson equation in the Euclidean space
topic Nuclear Theory
High Energy Physics - Theory
url https://arxiv.org/abs/2401.11019