$η$ invariant of massive Wilson Dirac operator and the index

Fuente: arXiv
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Autori principali: Aoki, Shoto, Fukaya, Hidenori, Furuta, Mikio, Matsuo, Shinichiroh, Onogi, Tetsuya, Yamaguchi, Satoshi
Natura: Preprint
Pubblicazione: 2025
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author Aoki, Shoto
Fukaya, Hidenori
Furuta, Mikio
Matsuo, Shinichiroh
Onogi, Tetsuya
Yamaguchi, Satoshi
author_facet Aoki, Shoto
Fukaya, Hidenori
Furuta, Mikio
Matsuo, Shinichiroh
Onogi, Tetsuya
Yamaguchi, Satoshi
contents We revisit the lattice index theorem in the perspective of $K$-theory. The standard definition given by the overlap Dirac operator equals to the $η$ invariant of the Wilson Dirac operator with a negative mass. This equality is not coincidental but reflects a mathematically profound significance known as the suspension isomorphism of $K$-groups. Specifically, we identify the Wilson Dirac operator as an element of the $K^1$ group, which is characterized by the $η$-invariant. Furthermore, we prove that, at sufficiently small but finite lattice spacings, this $η$-invariant equals to the index of the continuum Dirac operator. Our results indicate that the Ginsparg-Wilson relation and the associated exact chiral symmetry are not essential for understanding gauge field topology in lattice gauge theory.
format Preprint
id arxiv_https___arxiv_org_abs_2501_02873
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle $η$ invariant of massive Wilson Dirac operator and the index
Aoki, Shoto
Fukaya, Hidenori
Furuta, Mikio
Matsuo, Shinichiroh
Onogi, Tetsuya
Yamaguchi, Satoshi
High Energy Physics - Lattice
Strongly Correlated Electrons
High Energy Physics - Theory
K-Theory and Homology
We revisit the lattice index theorem in the perspective of $K$-theory. The standard definition given by the overlap Dirac operator equals to the $η$ invariant of the Wilson Dirac operator with a negative mass. This equality is not coincidental but reflects a mathematically profound significance known as the suspension isomorphism of $K$-groups. Specifically, we identify the Wilson Dirac operator as an element of the $K^1$ group, which is characterized by the $η$-invariant. Furthermore, we prove that, at sufficiently small but finite lattice spacings, this $η$-invariant equals to the index of the continuum Dirac operator. Our results indicate that the Ginsparg-Wilson relation and the associated exact chiral symmetry are not essential for understanding gauge field topology in lattice gauge theory.
title $η$ invariant of massive Wilson Dirac operator and the index
topic High Energy Physics - Lattice
Strongly Correlated Electrons
High Energy Physics - Theory
K-Theory and Homology
url https://arxiv.org/abs/2501.02873