2014/08/05 by Scott Geraedts, Olexei I. Motrunich, Olexei Motrunich
Physics and Astronomy · #Advanced Condensed Matter Physics #Boson #Charge (physics) #Charge conservation #Lattice (music) #Phase (matter) #Phase diagram #Physics #Quantum #Quantum many-body systems #Quantum mechanics #Superfluidity #Symmetry protected topological order #Topological Materials and Phenomena #Topological insulator #Topological order #Topological quantum number #Topology (electrical circuits) #cond-mat.stat-mech #cond-mat.str-el #hep-lat
paper · pdf · doi:10.1103/physrevx.4.041049
published as Phys. Rev. X 4, 041049 (2014) · 26 pages, 16 figures
arxiv created 2014/08/05 · openalex publication_date 2014/12/22 · arxiv updated 2014/12/31 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We study a topological phase of interacting bosons in (3 1) dimensions that is protected by charge conservation and time-reversal symmetry. We present an explicit lattice model that realizes this phase and that can be studied in sign-free Monte Carlo simulations. The idea behind our model is to bind bosons to topological defects called hedgehogs. We determine the phase diagram of the model and identify a phase where such bound states are proliferated. In this phase, we observe a Witten effect in the bulk whereby an external monopole binds half of the elementary boson charge, which confirms that it is a bosonic topological insulator. We also study the boundary between the topological insulator and a trivial insulator. We find a surface phase diagram that includes exotic superfluids, a topologically ordered phase, and a phase with a Hall effect quantized to one-half of the value possible in a purely two-dimensional system. We also present models that realize symmetry-enriched topologically ordered phases by binding multiple hedgehogs to each boson; these phases show charge fractionalization and intrinsic topological order as well as a fractional Witten effect.