English

Computing the center of a fusion category

Representation Theory 2025-11-10 v2 Mathematical Physics Category Theory math.MP Quantum Algebra

Abstract

We present an algorithm for explicitly computing the categorical (Drinfeld) center of a pivotal fusion category. Our approach is based on decomposing the images of simple objects under the induction functor from the category to its center. We have implemented this algorithm in a general-purpose software framework TensorCategories.jl for tensor categories that we develop within the open-source computer algebra system OSCAR. We compute explicit models for the centers in form of the tuples (X,γ)(X,\gamma) where XX is an object and γ\gamma is a half-braiding. From these models we can compute the FF-symbols and RR-symbols. Using the data from the AnyonWiki, we were able to compute the center together with its FF-symbols and RR-symbols for all the 279 multiplicity-free fusion categories up to rank 5, and furthermore some chosen examples of rank 6, including the Haagerup subfactor (presented in a separate paper).

Keywords

Cite

@article{arxiv.2406.13438,
  title  = {Computing the center of a fusion category},
  author = {Fabian Mäurer and Ulrich Thiel},
  journal= {arXiv preprint arXiv:2406.13438},
  year   = {2025}
}

Comments

Expanded version: Added computation of the center of all multiplicity-free fusion categories up to rank 5 together with their F-symbols and R-symbols