Two-dimensional topological paramagnets protected by $\mathbb{Z}_3$ symmetry: Properties of the boundary Hamiltonian

We systematically study gapless edge modes corresponding to $\mathbb{Z}_3$ symmetry-protected topological (SPT) phases of two-dimensional three-state Potts paramagnets on a triangular lattice. First, we derive microscopic lattice models for the gapless edge and, using the density-matrix renormalizat...

Full description

Saved in:
Bibliographic Details
Main Author: Hrant Topchyan, Vasilii Iugov, Mkhitar Mirumyan, Tigran Hakobyan, Tigran A. Sedrakyan, Ara G. Sedrakyan
Format: Article
Language:English
Published: SciPost 2025-02-01
Series:SciPost Physics
Online Access:https://scipost.org/SciPostPhys.18.2.068
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849723345475469312
author Hrant Topchyan, Vasilii Iugov, Mkhitar Mirumyan, Tigran Hakobyan, Tigran A. Sedrakyan, Ara G. Sedrakyan
author_facet Hrant Topchyan, Vasilii Iugov, Mkhitar Mirumyan, Tigran Hakobyan, Tigran A. Sedrakyan, Ara G. Sedrakyan
author_sort Hrant Topchyan, Vasilii Iugov, Mkhitar Mirumyan, Tigran Hakobyan, Tigran A. Sedrakyan, Ara G. Sedrakyan
collection DOAJ
description We systematically study gapless edge modes corresponding to $\mathbb{Z}_3$ symmetry-protected topological (SPT) phases of two-dimensional three-state Potts paramagnets on a triangular lattice. First, we derive microscopic lattice models for the gapless edge and, using the density-matrix renormalization group (DMRG) approach, investigate the finite-size scaling of the low-lying excitation spectrum and the entanglement entropy. Based on the obtained results, we identify the universality class of the critical edge, namely the corresponding conformal field theory and the central charge. Finally, we discuss the inherent symmetries of the edge models and the emergent winding number symmetry. As a result, one-dimensional chains with this symmetry form a model that supports gapless excitations due to its tricritical symmetry. Numerically, we show that low-energy states in the continuous limit of the edge model can be described by conformal field theory (CFT) with central charge $c=1$, given by the coset $SU_k(3)/SU_k(2)$ CFT at level k=1.
format Article
id doaj-art-e964c9215ce74eec822d1296d29cedfc
institution DOAJ
issn 2542-4653
language English
publishDate 2025-02-01
publisher SciPost
record_format Article
series SciPost Physics
spelling doaj-art-e964c9215ce74eec822d1296d29cedfc2025-08-20T03:11:03ZengSciPostSciPost Physics2542-46532025-02-0118206810.21468/SciPostPhys.18.2.068Two-dimensional topological paramagnets protected by $\mathbb{Z}_3$ symmetry: Properties of the boundary HamiltonianHrant Topchyan, Vasilii Iugov, Mkhitar Mirumyan, Tigran Hakobyan, Tigran A. Sedrakyan, Ara G. SedrakyanWe systematically study gapless edge modes corresponding to $\mathbb{Z}_3$ symmetry-protected topological (SPT) phases of two-dimensional three-state Potts paramagnets on a triangular lattice. First, we derive microscopic lattice models for the gapless edge and, using the density-matrix renormalization group (DMRG) approach, investigate the finite-size scaling of the low-lying excitation spectrum and the entanglement entropy. Based on the obtained results, we identify the universality class of the critical edge, namely the corresponding conformal field theory and the central charge. Finally, we discuss the inherent symmetries of the edge models and the emergent winding number symmetry. As a result, one-dimensional chains with this symmetry form a model that supports gapless excitations due to its tricritical symmetry. Numerically, we show that low-energy states in the continuous limit of the edge model can be described by conformal field theory (CFT) with central charge $c=1$, given by the coset $SU_k(3)/SU_k(2)$ CFT at level k=1.https://scipost.org/SciPostPhys.18.2.068
spellingShingle Hrant Topchyan, Vasilii Iugov, Mkhitar Mirumyan, Tigran Hakobyan, Tigran A. Sedrakyan, Ara G. Sedrakyan
Two-dimensional topological paramagnets protected by $\mathbb{Z}_3$ symmetry: Properties of the boundary Hamiltonian
SciPost Physics
title Two-dimensional topological paramagnets protected by $\mathbb{Z}_3$ symmetry: Properties of the boundary Hamiltonian
title_full Two-dimensional topological paramagnets protected by $\mathbb{Z}_3$ symmetry: Properties of the boundary Hamiltonian
title_fullStr Two-dimensional topological paramagnets protected by $\mathbb{Z}_3$ symmetry: Properties of the boundary Hamiltonian
title_full_unstemmed Two-dimensional topological paramagnets protected by $\mathbb{Z}_3$ symmetry: Properties of the boundary Hamiltonian
title_short Two-dimensional topological paramagnets protected by $\mathbb{Z}_3$ symmetry: Properties of the boundary Hamiltonian
title_sort two dimensional topological paramagnets protected by mathbb z 3 symmetry properties of the boundary hamiltonian
url https://scipost.org/SciPostPhys.18.2.068
work_keys_str_mv AT hranttopchyanvasiliiiugovmkhitarmirumyantigranhakobyantigranasedrakyanaragsedrakyan twodimensionaltopologicalparamagnetsprotectedbymathbbz3symmetrypropertiesoftheboundaryhamiltonian