Gapped Boundary Phases of Topological Insulators via Weak Coupling

Abstract

The standard boundary state of a topological insulator in 3+1 dimensions has gapless charged fermions. We present model systems that reproduce this standard gapless boundary state in one phase, but also have gapped phases with topological order. Our models are weakly coupled and all the dynamics is explicit. We rederive some known boundary states of topological insulators and construct new ones. Consistency with the standard spin/charge relation of condensed matter physics places a nontrivial constraint on models.

86 pages, minor changes

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Cited by in corpus (8)

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• Dai-Freed theorem and topological phases of matter
• More on time-reversal anomaly of 2+1d topological phases
• Symmetry enhancement and closing of knots in 3d/3d correspondence
• A Matrix Model for Non-Abelian Quantum Hall States
• Three-dimensional Topological Insulators and Bosonization
• Gauge interactions and topological phases of matter