Tree tensor network impurity solver based on Cayley-tree mapping

Fuente: arXiv
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Main Authors: Zhan, Bo, Chen, Jia-Lin, Fan, Zhen, Xiang, Tao
Format: Preprint
Published: 2026
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author Zhan, Bo
Chen, Jia-Lin
Fan, Zhen
Xiang, Tao
author_facet Zhan, Bo
Chen, Jia-Lin
Fan, Zhen
Xiang, Tao
contents We introduce a tree tensor network (TTN) impurity solver that enables highly efficient and accurate real-time simulations of quantum impurity models. By decomposing a noninteracting bath Hamiltonian into a Cayley tree, the method provides a tensor network representation that naturally captures the multiscale entanglement structure intrinsic to impurity-bath systems. This geometry differs from conventional chain-based mappings and yields a substantial reduction of entanglement, allowing accurate ground-state properties and long-time dynamics to be captured at significantly lower bond dimensions. Benchmark calculations for the single-impurity Anderson model demonstrate that the TTN solver achieves markedly enhanced resolution of real-frequency spectral functions, without invoking analytic continuation. This impurity solver provides a balanced, scale-uniform description of impurity physics and offers a versatile approach for real-time dynamical mean-field theory and related applications involving quantum impurity models.
format Preprint
id arxiv_https___arxiv_org_abs_2601_17718
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Tree tensor network impurity solver based on Cayley-tree mapping
Zhan, Bo
Chen, Jia-Lin
Fan, Zhen
Xiang, Tao
Strongly Correlated Electrons
We introduce a tree tensor network (TTN) impurity solver that enables highly efficient and accurate real-time simulations of quantum impurity models. By decomposing a noninteracting bath Hamiltonian into a Cayley tree, the method provides a tensor network representation that naturally captures the multiscale entanglement structure intrinsic to impurity-bath systems. This geometry differs from conventional chain-based mappings and yields a substantial reduction of entanglement, allowing accurate ground-state properties and long-time dynamics to be captured at significantly lower bond dimensions. Benchmark calculations for the single-impurity Anderson model demonstrate that the TTN solver achieves markedly enhanced resolution of real-frequency spectral functions, without invoking analytic continuation. This impurity solver provides a balanced, scale-uniform description of impurity physics and offers a versatile approach for real-time dynamical mean-field theory and related applications involving quantum impurity models.
title Tree tensor network impurity solver based on Cayley-tree mapping
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2601.17718