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arXiv · 1905.05790

A UV perspective on mixed anomalies at critical points between bosonic symmetry-protected phases

Nick Bultinck
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Abstract

Symmetry-protected phases are gapped phases of matter which are distinguished only in the presence of a global symmetry G. These quantum phases lack any symmetry-breaking or topological order, and have short-range entangled ground states. Based on this short-range entanglement property, we give a general argument for the existence of an emergent unitary or anti-unitary $\mathbb{Z}_2$ symmetry at a critical point separating two different bosonic symmetry-protected phases in any dimension. Often, the emergent symmetry group at criticality has a mixed global anomaly. For those phases classified by group cohomology, we identify a criterion for when such a mixed global anomaly is present, and write down representative cocycles for the corresponding anomaly class. We illustrate our results with a series of examples, and make connections to recent results on (2 + 1)-d beyond-Landau critical points.

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Nick Bultinck. 2019-10-19. A UV perspective on mixed anomalies at critical points between bosonic symmetry-protected phases. https://doi.org/10.1103/physrevb.100.165132

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