English

Commuting-projector Hamiltonians for chiral topological phases built from parafermions

Strongly Correlated Electrons 2018-07-04 v1 Mesoscale and Nanoscale Physics

Abstract

We introduce a family of commuting-projector Hamiltonians whose degrees of freedom involve Z3\mathbb{Z}_{3} parafermion zero modes residing in a parent fractional-quantum-Hall fluid. The two simplest models in this family emerge from dressing Ising-paramagnet and toric-code spin models with parafermions; we study their edge properties, anyonic excitations, and ground-state degeneracy. We show that the first model realizes a symmetry-enriched topological phase (SET) for which Z2\mathbb{Z}_2 spin-flip symmetry from the Ising paramagnet permutes the anyons. Interestingly, the interface between this SET and the parent quantum-Hall phase realizes symmetry-enforced Z3\mathbb{Z}_3 parafermion criticality with no fine-tuning required. The second model exhibits a non-Abelian phase that is consistent with SU(2)4\text{SU}(2)_{4} topological order, and can be accessed by gauging the Z2\mathbb{Z}_{2} symmetry in the SET. Employing Levin-Wen string-net models with Z2\mathbb{Z}_{2}-graded structure, we generalize this picture to construct a large class of commuting-projector models for Z2\mathbb{Z}_{2} SETs and non-Abelian topological orders exhibiting the same relation. Our construction provides the first commuting-projector-Hamiltonian realization of chiral bosonic non-Abelian topological order.

Keywords

Cite

@article{arxiv.1803.11195,
  title  = {Commuting-projector Hamiltonians for chiral topological phases built from parafermions},
  author = {Jun Ho Son and Jason Alicea},
  journal= {arXiv preprint arXiv:1803.11195},
  year   = {2018}
}

Comments

29+18 pages, 25 figures