Topological defect lines in two dimensional fermionic CFTs

We consider topological defect lines (TDLs) in two-dimensional fermionic conformal field theories (CFTs). Besides inheriting all the properties of TDLs in bosonic CFTs, TDLs in fermionic CFTs could host fermionic defect operators at their endpoints and junctions. Furthermore, there is a new type of...

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Main Author: Chi-Ming Chang, Jin Chen, Fengjun Xu
Format: Article
Language:English
Published: SciPost 2023-11-01
Series:SciPost Physics
Online Access:https://scipost.org/SciPostPhys.15.5.216
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author Chi-Ming Chang, Jin Chen, Fengjun Xu
author_facet Chi-Ming Chang, Jin Chen, Fengjun Xu
author_sort Chi-Ming Chang, Jin Chen, Fengjun Xu
collection DOAJ
description We consider topological defect lines (TDLs) in two-dimensional fermionic conformal field theories (CFTs). Besides inheriting all the properties of TDLs in bosonic CFTs, TDLs in fermionic CFTs could host fermionic defect operators at their endpoints and junctions. Furthermore, there is a new type of TDLs, called q-type TDLs, that have no analog in bosonic CFTs. Their distinguishing feature is an extra one-dimensional Majorana fermion living on the worldline of the TDLs. The properties of TDLs in fermionic CFTs are captured in the mathematical language of the super fusion category. We propose a classification of the rank-2 super fusion categories generalizing the $\mathbb{Z}_8$ classification for the anomalies of $\mathbb{Z}_2$ symmetries. We explicitly solve the F-moves for all the nontrivial categories, and derive the corresponding spin selection rules that constrain the spectrum of the defect operators. We find the full set of TDLs in the standard fermionic minimal models and a partial set of TDLs in the two exceptional models, which give CFT realizations to the rank-2 super fusion categories. Finally, we discuss a constraint on the renormalization group flow that preserves a q-type TDL.
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spelling doaj.art-4c75fdd8b997401491c3f5de8edc9f0b2023-11-29T12:33:50ZengSciPostSciPost Physics2542-46532023-11-0115521610.21468/SciPostPhys.15.5.216Topological defect lines in two dimensional fermionic CFTsChi-Ming Chang, Jin Chen, Fengjun XuWe consider topological defect lines (TDLs) in two-dimensional fermionic conformal field theories (CFTs). Besides inheriting all the properties of TDLs in bosonic CFTs, TDLs in fermionic CFTs could host fermionic defect operators at their endpoints and junctions. Furthermore, there is a new type of TDLs, called q-type TDLs, that have no analog in bosonic CFTs. Their distinguishing feature is an extra one-dimensional Majorana fermion living on the worldline of the TDLs. The properties of TDLs in fermionic CFTs are captured in the mathematical language of the super fusion category. We propose a classification of the rank-2 super fusion categories generalizing the $\mathbb{Z}_8$ classification for the anomalies of $\mathbb{Z}_2$ symmetries. We explicitly solve the F-moves for all the nontrivial categories, and derive the corresponding spin selection rules that constrain the spectrum of the defect operators. We find the full set of TDLs in the standard fermionic minimal models and a partial set of TDLs in the two exceptional models, which give CFT realizations to the rank-2 super fusion categories. Finally, we discuss a constraint on the renormalization group flow that preserves a q-type TDL.https://scipost.org/SciPostPhys.15.5.216
spellingShingle Chi-Ming Chang, Jin Chen, Fengjun Xu
Topological defect lines in two dimensional fermionic CFTs
SciPost Physics
title Topological defect lines in two dimensional fermionic CFTs
title_full Topological defect lines in two dimensional fermionic CFTs
title_fullStr Topological defect lines in two dimensional fermionic CFTs
title_full_unstemmed Topological defect lines in two dimensional fermionic CFTs
title_short Topological defect lines in two dimensional fermionic CFTs
title_sort topological defect lines in two dimensional fermionic cfts
url https://scipost.org/SciPostPhys.15.5.216
work_keys_str_mv AT chimingchangjinchenfengjunxu topologicaldefectlinesintwodimensionalfermioniccfts