Relation between winding numbers and energy dispersions

Fuente: arXiv
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Main Authors: Liu, Quancheng, Ziegler, Klaus
Format: Preprint
Published: 2025
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author Liu, Quancheng
Ziegler, Klaus
author_facet Liu, Quancheng
Ziegler, Klaus
contents Two-band Hamiltonians provide a typical description of topological band structures, in which the eigenfunctions can be characterized by a %Bloch vector field whose winding number that defines an integer topological invariant. This winding number is quantized and protected against continuous deformations of the Hamiltonian. Here we show that the Bloch vector and its winding number can be directly related to the gradient of the energy dispersion. Since the energy gradient is proportional to the group velocity, our result establishes an experimentally accessible correspondence between the Bloch vector field and angle-resolved photoemission spectroscopy measurements. We discuss a mapping between the gradient of the energy dispersion and the Bloch vector. This implies a direct and measurable relation between two-band Hamiltonians and their underlying topological structures.
format Preprint
id arxiv_https___arxiv_org_abs_2512_23685
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Relation between winding numbers and energy dispersions
Liu, Quancheng
Ziegler, Klaus
Mesoscale and Nanoscale Physics
Two-band Hamiltonians provide a typical description of topological band structures, in which the eigenfunctions can be characterized by a %Bloch vector field whose winding number that defines an integer topological invariant. This winding number is quantized and protected against continuous deformations of the Hamiltonian. Here we show that the Bloch vector and its winding number can be directly related to the gradient of the energy dispersion. Since the energy gradient is proportional to the group velocity, our result establishes an experimentally accessible correspondence between the Bloch vector field and angle-resolved photoemission spectroscopy measurements. We discuss a mapping between the gradient of the energy dispersion and the Bloch vector. This implies a direct and measurable relation between two-band Hamiltonians and their underlying topological structures.
title Relation between winding numbers and energy dispersions
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2512.23685