Anyon condensation and a generic tensor-network construction for symmetry protected topological phases

TL;DR

This paper develops tensor-network wavefunctions for bosonic SPT phases with onsite and spatial symmetries, classifies them via cohomology, and links SPT and SET phases through anyon condensation.

Contribution

It provides a systematic tensor-network construction for SPT phases in various dimensions considering complex symmetries, and reveals a connection between SPT and SET phases.

Findings

Cohomological classification of SPT phases in 1D, 2D, 3D with spatial symmetries.

Explicit tensor-network wavefunctions for various SPT phases.

Connection between SPT and SET phases via anyon condensation.

Abstract

We present systematic constructions of tensor-network wavefunctions for bosonic symmetry protected topological (SPT) phases respecting both onsite and spatial symmetries. From the classification point of view, our results show that in spatial dimensions $d=1,2,3$, the cohomological bosonic SPT phases protected by a general symmetry group $SG$ involving onsite and spatial symmetries are classified by the cohomology group $H^{d+1}(SG,U(1))$, in which both the time-reversal symmetry and mirror reflection symmetries should be treated as anti-unitary operations. In addition, for every SPT phase protected by a discrete symmetry group and some SPT phases protected by continous symmetry groups, generic tensor-network wavefunctions can be constructed which would be useful for the purpose of variational numerical simulations. As a by-product, our results demonstrate a generic connection between rather conventional symmetry enriched topological phases and SPT phases via an anyon condensation mechanism.