Drinfeld centers of fusion categories arising from generalized Haagerup subfactors

Abstract

We consider generalized Haagerup categories such that 1 ⊕ X admits a Q-system for every non-invertible simple object X. We show that in such a category, the group of order two invertible objects has size at most four. We describe the simple objects of the Drinfeld center and give partial formulas for the modular data. We compute the remaining corner of the modular data for several examples and make conjectures about the general case.We also consider several types of equivariantizations and de-equivariantizations of generalized Haagerup categories and describe their Drinfeld centers. In particular, we compute the modular data for the Drinfeld centers of a number of examples of fusion categories arising in the classification of small-index subfactors: the Asaeda–Haagerup subfactor; the 3[ℤ4] and 3[ℤ2×ℤ2] subfactors; the 2D2 subfactor; and the 4442 subfactor. The results suggest the possibility of several new infinite families of quadratic categories. A description and generalization of the modular data associated to these families in terms of pairs of metric groups is taken up in the accompanying paper [Comm. Math. Phys. 380 (2020), 1091–1150].