Defect Networks for Topological Phases Protected By Modulated Symmetries

TL;DR

This paper introduces a framework for constructing and classifying topological phases protected by modulated symmetries, such as dipolar symmetries, using defect networks, and explores their anomalies and classifications in various dimensions.

Contribution

It generalizes the crystalline equivalence principle to modulated symmetries and provides a systematic method for classifying symmetry-protected topological phases with these symmetries.

Findings

Constructed topological phases using defect networks for modulated symmetries.

Identified conditions under which defect networks become anomalous.

Classified SPT phases protected by translation and dipolar symmetries in (1+1)D and (2+1)D.

Abstract

Modulated symmetries are internal symmetries which do not commute with spatial symmetries; dipolar symmetries are a prime example. We give a general recipe for constructing topological phases protected by modulated symmetries via a defect network construction, generalizing the crystalline equivalence principle to modulated symmetries. We demonstrate that modulated symmetries can be treated identically to unmodulated symmetries in the absence of spatial symmetries, but in the presence of spatial symmetries, some defect networks which are non-anomalous for unmodulated symmetries become anomalous for modulated symmetries. We apply this understanding to classify symmetry-protected topological phases protected by translation symmetry plus either discrete or continuous dipolar symmetries in (1+1)D and (2+1)D and obtain a number of other (1+1)D classification results for modulated symmetry-protected topological phases.