Microscopic models for Kitaev's sixteenfold way of anyon theories

TL;DR

This paper constructs and analyzes microscopic models for Kitaev's sixteenfold way of anyon theories, providing exact solutions and characterizations of topological order for different spectral Chern numbers.

Contribution

It offers a systematic, complete construction of microscopic models realizing the sixteenfold way, including their solvability and topological properties.

Findings

Models are exactly solvable via Majorana representation.

Topological spin and ground-state degeneracy are characterized.

Models are defined on square or honeycomb lattices depending on ff.

Abstract

In two dimensions, the topological order described by $\mathbb{Z}_2$ gauge theory coupled to free or weakly interacting fermions with a nonzero spectral Chern number $\nu$ is classified by $\nu \; \mathrm{mod}\; 16$ as predicted by Kitaev [Ann. Phys. 321, 2 (2006)]. Here we provide a systematic and complete construction of microscopic models realizing this so-called sixteenfold way of anyon theories. These models are defined by $\Gamma$ matrices satisfying the Clifford algebra, enjoy a global $\mathrm{SO}(\nu)$ symmetry, and live on either square or honeycomb lattices depending on the parity of $\nu$. We show that all these models are exactly solvable by using a Majorana representation and characterize the topological order by calculating the topological spin of an anyonic quasiparticle and the ground-state degeneracy. The possible relevance of the $\nu=2$ and $\nu=3$ models to materials with Kugel-Khomskii-type spin-orbital interactions is discussed.