Relation between chiral central charge and ground-state degeneracy in ( 2 + 1 ) -dimensional topological orders

A bosonic topological order on $d$-dimensional closed space $\Sigma^d$ may have degenerate ground states. The space $\Sigma^d$ with different shapes (different metrics) form a moduli space ${\cal M}_{\Sigma^d}$. Thus the degenerate ground states on every point in the moduli space ${\cal M}_{\Sigma^d...

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Main Authors: Kong, Liang, Wen, Xiao-Gang
Other Authors: Massachusetts Institute of Technology. Department of Physics
Format: Article
Language:English
Published: American Physical Society (APS) 2021
Online Access:https://hdl.handle.net/1721.1/135326
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author Kong, Liang
Wen, Xiao-Gang
author2 Massachusetts Institute of Technology. Department of Physics
author_facet Massachusetts Institute of Technology. Department of Physics
Kong, Liang
Wen, Xiao-Gang
author_sort Kong, Liang
collection MIT
description A bosonic topological order on $d$-dimensional closed space $\Sigma^d$ may have degenerate ground states. The space $\Sigma^d$ with different shapes (different metrics) form a moduli space ${\cal M}_{\Sigma^d}$. Thus the degenerate ground states on every point in the moduli space ${\cal M}_{\Sigma^d}$ form a complex vector bundle over ${\cal M}_{\Sigma^d}$. It was suggested that the collection of such vector bundles for $d$-dimensional closed spaces of all topologies completely characterizes the topological order. Using such a point of view, we propose a direct relation between two seemingly unrelated properties of 2+1-dimensional topological orders: (1) the chiral central charge $c$ that describes the many-body density of states for edge excitations (or more precisely the thermal Hall conductance of the edge), (2) the ground state degeneracy $D_g$ on closed genus $g$ surface. We show that $c D_g/2 \in \mathbb{Z},\ g\geq 3$ for bosonic topological orders. We explicitly checked the validity of this relation for over 140 simple topological orders. For fermionic topological orders, let $D_{g,\sigma}^{e}$ ($D_{g,\sigma}^{o}$) be the degeneracy with even (odd) number of fermions for genus-$g$ surface with spin structure $\sigma$. Then we have $2c D_{g,\sigma}^{e} \in \mathbb{Z}$ and $2c D_{g,\sigma}^{o} \in \mathbb{Z}$ for $g\geq 3$.
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spelling mit-1721.1/1353262023-03-15T19:46:01Z Relation between chiral central charge and ground-state degeneracy in ( 2 + 1 ) -dimensional topological orders Kong, Liang Wen, Xiao-Gang Massachusetts Institute of Technology. Department of Physics A bosonic topological order on $d$-dimensional closed space $\Sigma^d$ may have degenerate ground states. The space $\Sigma^d$ with different shapes (different metrics) form a moduli space ${\cal M}_{\Sigma^d}$. Thus the degenerate ground states on every point in the moduli space ${\cal M}_{\Sigma^d}$ form a complex vector bundle over ${\cal M}_{\Sigma^d}$. It was suggested that the collection of such vector bundles for $d$-dimensional closed spaces of all topologies completely characterizes the topological order. Using such a point of view, we propose a direct relation between two seemingly unrelated properties of 2+1-dimensional topological orders: (1) the chiral central charge $c$ that describes the many-body density of states for edge excitations (or more precisely the thermal Hall conductance of the edge), (2) the ground state degeneracy $D_g$ on closed genus $g$ surface. We show that $c D_g/2 \in \mathbb{Z},\ g\geq 3$ for bosonic topological orders. We explicitly checked the validity of this relation for over 140 simple topological orders. For fermionic topological orders, let $D_{g,\sigma}^{e}$ ($D_{g,\sigma}^{o}$) be the degeneracy with even (odd) number of fermions for genus-$g$ surface with spin structure $\sigma$. Then we have $2c D_{g,\sigma}^{e} \in \mathbb{Z}$ and $2c D_{g,\sigma}^{o} \in \mathbb{Z}$ for $g\geq 3$. 2021-10-27T20:22:58Z 2021-10-27T20:22:58Z 2020 2021-07-09T15:25:50Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/135326 en 10.1103/PHYSREVRESEARCH.2.033344 Physical Review Research Creative Commons Attribution 4.0 International license https://creativecommons.org/licenses/by/4.0/ application/pdf American Physical Society (APS) APS
spellingShingle Kong, Liang
Wen, Xiao-Gang
Relation between chiral central charge and ground-state degeneracy in ( 2 + 1 ) -dimensional topological orders
title Relation between chiral central charge and ground-state degeneracy in ( 2 + 1 ) -dimensional topological orders
title_full Relation between chiral central charge and ground-state degeneracy in ( 2 + 1 ) -dimensional topological orders
title_fullStr Relation between chiral central charge and ground-state degeneracy in ( 2 + 1 ) -dimensional topological orders
title_full_unstemmed Relation between chiral central charge and ground-state degeneracy in ( 2 + 1 ) -dimensional topological orders
title_short Relation between chiral central charge and ground-state degeneracy in ( 2 + 1 ) -dimensional topological orders
title_sort relation between chiral central charge and ground state degeneracy in 2 1 dimensional topological orders
url https://hdl.handle.net/1721.1/135326
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AT wenxiaogang relationbetweenchiralcentralchargeandgroundstatedegeneracyin21dimensionaltopologicalorders