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arXiv · 1404.2818

Microscopic Realization of 2-Dimensional Bosonic Topological Insulators

Zheng-Xin Liu·Zheng-Cheng Gu·Xiao-Gang Wen
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Abstract

It is well known that a Bosonic Mott insulator can be realized by condensing vortices of a bo- son condensate. Usually, a vortex becomes an anti-vortex (and vice-versa) under time reversal symmetry, and the condensation of vortices results in a trivial Mott insulator. However, if each vortex or anti-vortex interacts with a spin trapped at its core, the time reversal transformation of the composite vortex operator will contain an extra minus sign. It turns out that such a composite vortex condensed state is a bosonic topological insulator (BTI) with gapless boundary excitations protected by $U(1)\rtimes Z_2^T$ symmetry. We point out that in BTI, an external $π$ flux monodromy defect carries a Kramers doublet. We propose lattice model Hamiltonians to realize the BTI phase, which might be implemented in cold atom systems or spin-1 solid state systems.

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Zheng-Xin Liu, Zheng-Cheng Gu, Xiao-Gang Wen. 2015-01-04. Microscopic Realization of 2-Dimensional Bosonic Topological Insulators. https://doi.org/10.1103/physrevlett.113.267206

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