Boundary conformal field theory and symmetry-protected topological phases in 2 + 1 dimensions

We propose a diagnostic tool for detecting nontrivial symmetry-protected topological (SPT) phases protected by a symmetry group G in 2+1 dimensions. Our method is based on directly studying the 1+1-dimensional anomalous edge conformal field theory (CFT) of SPT phases. We claim that if the CFT is the...

Full description

Saved in:
Bibliographic Details
Published in:Physical review. B 2017-09, Vol.96 (12), Article 125105
Main Authors: Han, Bo, Tiwari, Apoorv, Hsieh, Chang-Tse, Ryu, Shinsei
Format: Article
Language:English
Subjects:
Diagnostic software
Diagnostic systems
Field theory
Phases
Symmetry
Topological insulators
Topological superconductors
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We propose a diagnostic tool for detecting nontrivial symmetry-protected topological (SPT) phases protected by a symmetry group G in 2+1 dimensions. Our method is based on directly studying the 1+1-dimensional anomalous edge conformal field theory (CFT) of SPT phases. We claim that if the CFT is the edge theory of an SPT phase, then there must be an obstruction to cutting it open. This obstruction manifests as the in-existence of boundary states in the CFT that preserves both the conformal symmetry and the global symmetry G. We discuss the relation between edgeability, i.e., the ability to find a consistent boundary state, and gappability, i.e., the ability to gap out a CFT, in the presence of G. We study several cases including time-reversal symmetric topological insulators, ZN symmetric bosonic SPT phases, and Z2×Z2 symmetric topological superconductors.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.96.125105