A linear algebra-based approach to understanding the relation between the winding number and zero-energy edge states

The one-to-one relation between the winding number and the number of robust zero-energy edge states, known as bulk-boundary correspondence, is a celebrated feature of 1$d$ systems with chiral symmetry. Although this property can be explained by the K-theory, the underlying mechanism remains elusive....

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Main Author: Chen-Shen Lee
Format: Article
Language:English
Published: SciPost 2024-01-01
Series:SciPost Physics Core
Online Access:https://scipost.org/SciPostPhysCore.7.1.003
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author Chen-Shen Lee
author_facet Chen-Shen Lee
author_sort Chen-Shen Lee
collection DOAJ
description The one-to-one relation between the winding number and the number of robust zero-energy edge states, known as bulk-boundary correspondence, is a celebrated feature of 1$d$ systems with chiral symmetry. Although this property can be explained by the K-theory, the underlying mechanism remains elusive. Here, we demonstrate that, even without resorting to advanced mathematical techniques, one can prove this correspondence and clearly illustrate the mechanism using only Cauchy's integral and elementary algebra. Furthermore, our approach to proving bulk-boundary correspondence also provides clear insights into a kind of system that doesn't respect chiral symmetry but can have robust left or right zero-energy edge states. In such systems, one can still assign the winding number to characterize these zero-energy edge states.
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spelling doaj.art-2cc229b217ef4b92bcc0e5b337d875c72024-01-30T15:39:33ZengSciPostSciPost Physics Core2666-93662024-01-017100310.21468/SciPostPhysCore.7.1.003A linear algebra-based approach to understanding the relation between the winding number and zero-energy edge statesChen-Shen LeeThe one-to-one relation between the winding number and the number of robust zero-energy edge states, known as bulk-boundary correspondence, is a celebrated feature of 1$d$ systems with chiral symmetry. Although this property can be explained by the K-theory, the underlying mechanism remains elusive. Here, we demonstrate that, even without resorting to advanced mathematical techniques, one can prove this correspondence and clearly illustrate the mechanism using only Cauchy's integral and elementary algebra. Furthermore, our approach to proving bulk-boundary correspondence also provides clear insights into a kind of system that doesn't respect chiral symmetry but can have robust left or right zero-energy edge states. In such systems, one can still assign the winding number to characterize these zero-energy edge states.https://scipost.org/SciPostPhysCore.7.1.003
spellingShingle Chen-Shen Lee
A linear algebra-based approach to understanding the relation between the winding number and zero-energy edge states
SciPost Physics Core
title A linear algebra-based approach to understanding the relation between the winding number and zero-energy edge states
title_full A linear algebra-based approach to understanding the relation between the winding number and zero-energy edge states
title_fullStr A linear algebra-based approach to understanding the relation between the winding number and zero-energy edge states
title_full_unstemmed A linear algebra-based approach to understanding the relation between the winding number and zero-energy edge states
title_short A linear algebra-based approach to understanding the relation between the winding number and zero-energy edge states
title_sort linear algebra based approach to understanding the relation between the winding number and zero energy edge states
url https://scipost.org/SciPostPhysCore.7.1.003
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