New Publication in Physical Review Letters

11.04.2018

Our publication on Global Anomaly Detection in Two-Dimensional Symmetry-Protected Topological Phases was published in Physical Review Letters.

Edge theories of symmetry-protected topological phases are well-known to possess global symmetry anomalies. In this work we focus on two-dimensional bosonic phases protected by an on-site symmetry and analyse the corresponding edge anomalies in more detail. Physical interpretations of the anomaly in terms of an obstruction to orbifolding and constructing symmetry-preserving boundaries are connected to the cohomology classification of symmetry-protected phases in two dimensions. Using the tensor network and matrix product state formalism we numerically illustrate our arguments and discuss computational detection schemes to identify symmetry-protected order in a ground state wave function.

 

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(a) Vertex operator with twisted boundary conditions labeled by group elements g,h and gh. (b) Operators associated to four-point functions of twist fields can be decomposed in two different ways in vertex operators.