Finite-temperature transport in the gapped spin-1/2 XXZ chain and one-dimensional lattice spinless fermion model

Fuente: arXiv
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Main Authors: Carmelo, J. M. P., Sacramento, P. D.
Format: Preprint
Published: 2025
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author Carmelo, J. M. P.
Sacramento, P. D.
author_facet Carmelo, J. M. P.
Sacramento, P. D.
contents Here we consider a class of energy eigenstates of the spin-1/2 XXZ chain that exist both for anisotropies 1 and larger than 1. We show that at the isotropic point their contributions are behind the diffusion constant being infinite, spin transport being anomalous superdiffusive for temperatures T>0. That for anisotropy larger than 1 such states do not contribute to the diffusion constant is shown to imply it is finite, spin transport being normal diffusive for T>0. By combining the connection through a Jordan-Wigner transformation of the spin-1/2 XXZ chain to the one-dimensional (1D) lattice spinless fermion model at zero chemical potential for V/J larger or equal to 1 with its Bethe-ansatz solution, where V is the nearest-neighbor Coulomb repulsion and J is twice the hopping integrai, in this paper we also address the issue of the T>0 charge transport of that model at zero chemical potential. It is found to be anomalous superdiffusive for V/J=1 and normal diffusive for V/J>1.
format Preprint
id arxiv_https___arxiv_org_abs_2509_08741
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Finite-temperature transport in the gapped spin-1/2 XXZ chain and one-dimensional lattice spinless fermion model
Carmelo, J. M. P.
Sacramento, P. D.
Strongly Correlated Electrons
Here we consider a class of energy eigenstates of the spin-1/2 XXZ chain that exist both for anisotropies 1 and larger than 1. We show that at the isotropic point their contributions are behind the diffusion constant being infinite, spin transport being anomalous superdiffusive for temperatures T>0. That for anisotropy larger than 1 such states do not contribute to the diffusion constant is shown to imply it is finite, spin transport being normal diffusive for T>0. By combining the connection through a Jordan-Wigner transformation of the spin-1/2 XXZ chain to the one-dimensional (1D) lattice spinless fermion model at zero chemical potential for V/J larger or equal to 1 with its Bethe-ansatz solution, where V is the nearest-neighbor Coulomb repulsion and J is twice the hopping integrai, in this paper we also address the issue of the T>0 charge transport of that model at zero chemical potential. It is found to be anomalous superdiffusive for V/J=1 and normal diffusive for V/J>1.
title Finite-temperature transport in the gapped spin-1/2 XXZ chain and one-dimensional lattice spinless fermion model
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2509.08741