Quantitative K-Theory Related to Spin Chern Numbers

We examine the various indices defined on pairs of almost commuting unitary matrices that can detect pairs that are far from commuting pairs. We do this in two symmetry classes, that of general unitary matrices and that of self-dual matrices, with an emphasis on quantitative results. We determine wh...

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Опубліковано в: :Symmetry, Integrability and Geometry: Methods and Applications
Дата:2014
Автор: Loring, T.A.
Формат: Стаття
Мова:English
Опубліковано: Інститут математики НАН України 2014
Онлайн доступ:https://nasplib.isofts.kiev.ua/handle/123456789/146609
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Назва журналу:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Цитувати:Quantitative K-Theory Related to Spin Chern Numbers / T.A. Loring // Symmetry, Integrability and Geometry: Methods and Applications. — 2014. — Т. 10. — Бібліогр.: 22 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
id nasplib_isofts_kiev_ua-123456789-146609
record_format dspace
spelling Loring, T.A.
2019-02-10T09:58:49Z
2019-02-10T09:58:49Z
2014
Quantitative K-Theory Related to Spin Chern Numbers / T.A. Loring // Symmetry, Integrability and Geometry: Methods and Applications. — 2014. — Т. 10. — Бібліогр.: 22 назв. — англ.
1815-0659
2010 Mathematics Subject Classification: 19M05; 46L60; 46L80
DOI:10.3842/SIGMA.2014.077
https://nasplib.isofts.kiev.ua/handle/123456789/146609
We examine the various indices defined on pairs of almost commuting unitary matrices that can detect pairs that are far from commuting pairs. We do this in two symmetry classes, that of general unitary matrices and that of self-dual matrices, with an emphasis on quantitative results. We determine which values of the norm of the commutator guarantee that the indices are defined, where they are equal, and what quantitative results on the distance to a pair with a different index are possible. We validate a method of computing spin Chern numbers that was developed with Hastings and only conjectured to be correct. Specifically, the Pfaffian-Bott index can be computed by the ''log method'' for commutator norms up to a specific constant.
This paper is a contribution to the Special Issue on Noncommutative Geometry and Quantum Groups in honor of Marc A. Rief fel. The full collection is available at http://www.emis.de/journals/SIGMA/Rieffel.html. The author wishes to thank Matt Hastings and Fredy Vides for discussions, both useful and entertaining. Also he wishes to thank Robert Israel and Nick Weaver for help via MathOverflow. Finally, thanks are due to the anonymous referees, whose suggestions improved the paper, especially Sections 3 and 4. This work was partially supported by a grant from the Simons Foundation (208723 to Loring).
en
Інститут математики НАН України
Symmetry, Integrability and Geometry: Methods and Applications
Quantitative K-Theory Related to Spin Chern Numbers
Article
published earlier
institution Digital Library of Periodicals of National Academy of Sciences of Ukraine
collection DSpace DC
title Quantitative K-Theory Related to Spin Chern Numbers
spellingShingle Quantitative K-Theory Related to Spin Chern Numbers
Loring, T.A.
title_short Quantitative K-Theory Related to Spin Chern Numbers
title_full Quantitative K-Theory Related to Spin Chern Numbers
title_fullStr Quantitative K-Theory Related to Spin Chern Numbers
title_full_unstemmed Quantitative K-Theory Related to Spin Chern Numbers
title_sort quantitative k-theory related to spin chern numbers
author Loring, T.A.
author_facet Loring, T.A.
publishDate 2014
language English
container_title Symmetry, Integrability and Geometry: Methods and Applications
publisher Інститут математики НАН України
format Article
description We examine the various indices defined on pairs of almost commuting unitary matrices that can detect pairs that are far from commuting pairs. We do this in two symmetry classes, that of general unitary matrices and that of self-dual matrices, with an emphasis on quantitative results. We determine which values of the norm of the commutator guarantee that the indices are defined, where they are equal, and what quantitative results on the distance to a pair with a different index are possible. We validate a method of computing spin Chern numbers that was developed with Hastings and only conjectured to be correct. Specifically, the Pfaffian-Bott index can be computed by the ''log method'' for commutator norms up to a specific constant.
issn 1815-0659
url https://nasplib.isofts.kiev.ua/handle/123456789/146609
citation_txt Quantitative K-Theory Related to Spin Chern Numbers / T.A. Loring // Symmetry, Integrability and Geometry: Methods and Applications. — 2014. — Т. 10. — Бібліогр.: 22 назв. — англ.
work_keys_str_mv AT loringta quantitativektheoryrelatedtospinchernnumbers
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last_indexed 2025-12-07T19:33:57Z
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