Conformal Net Realizability of Tambara-Yamagami Categories and Generalized Metaplectic Modular Categories

Abstract

We show that all isomorphism classes of even rank Tambara-Yamagami categories arise as $\mathbb{Z}_2$-twisted representations of conformal nets. As a consequence, we show that their Drinfel'd centers are realized by (generalized) orbifolds of conformal nets associated with (self-dual) lattices. The quantum double subfactors of even rank Tambara-Yamagami categories are Bisch-Haagerup subfactors and we describe their (dual) principal graphs. For every abelian group of odd order the Drinfel'd centers of the associated Tambara-Yamagami categories give a fusion ring generalizing the Verlinde ring $\mathrm{Spin}(2n+1)_2$ in the case of $\mathbb{Z}_{2n+1}$. We classify all generalized metaplectic modular categories, i.e. unitary modular tensor category with those fusion rules and show that they are realized as $\mathbb{Z}_2$-orbifolds of conformal nets associated with lattices. We further show that twisted doubles of generalized dihedral groups of abelian groups of odd order are group-theoretical generalized metaplectic modular categories and vice versa. We give some examples of twisted orbifolds of conformal nets and show how generalized metaplectic modular categories arise by condensation of simpler ones.