Proof of bulk-edge correspondence for band topology by Toeplitz algebra

Fuente: arXiv
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Main Authors: Zhou, Zixian, Wan, Liang-Liang
Format: Preprint
Published: 2024
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author Zhou, Zixian
Wan, Liang-Liang
author_facet Zhou, Zixian
Wan, Liang-Liang
contents We rigorously yet concisely prove the bulk-edge correspondence for general $d$-dimensional ($d$D) topological insulators in complex Altland-Zirnbauer classes, which states that the bulk topological number equals to the edge-mode index. Specifically, an essential formula is discovered that links the quantity expressed by Toeplitz algebra, i.e., hopping terms on the lattice with an edge, to the Fourier series on the bulk Brillouin zone. We then apply it to chiral models and utilize exterior differential calculations, instead of the sophisticated \emph{K}-theory, to show that the winding number of bulk system equals to the Fredholm index of 1D edge Hamiltonian, or to the sum of edge winding numbers for higher odd dimensions. Moreover, this result is inherited to the even-dimensional Chern insulators as each of them can be mapped to an odd-dimensional chiral model. It is revealed that the Chern number of bulk system is identical to the spectral flow of 2D edge Hamiltonian, or to the negative sum of edge Chern numbers for higher even dimensions. Our methods and conclusions are friendly to physicists and could be easily extended to other physical scenarios.
format Preprint
id arxiv_https___arxiv_org_abs_2410_19539
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Proof of bulk-edge correspondence for band topology by Toeplitz algebra
Zhou, Zixian
Wan, Liang-Liang
Mesoscale and Nanoscale Physics
Mathematical Physics
We rigorously yet concisely prove the bulk-edge correspondence for general $d$-dimensional ($d$D) topological insulators in complex Altland-Zirnbauer classes, which states that the bulk topological number equals to the edge-mode index. Specifically, an essential formula is discovered that links the quantity expressed by Toeplitz algebra, i.e., hopping terms on the lattice with an edge, to the Fourier series on the bulk Brillouin zone. We then apply it to chiral models and utilize exterior differential calculations, instead of the sophisticated \emph{K}-theory, to show that the winding number of bulk system equals to the Fredholm index of 1D edge Hamiltonian, or to the sum of edge winding numbers for higher odd dimensions. Moreover, this result is inherited to the even-dimensional Chern insulators as each of them can be mapped to an odd-dimensional chiral model. It is revealed that the Chern number of bulk system is identical to the spectral flow of 2D edge Hamiltonian, or to the negative sum of edge Chern numbers for higher even dimensions. Our methods and conclusions are friendly to physicists and could be easily extended to other physical scenarios.
title Proof of bulk-edge correspondence for band topology by Toeplitz algebra
topic Mesoscale and Nanoscale Physics
Mathematical Physics
url https://arxiv.org/abs/2410.19539