English

Modularization of small quantum groups

Quantum Algebra 2018-09-11 v2 High Energy Physics - Theory Representation Theory

Abstract

We construct a large family of ribbon quasi-Hopf algebras related to small quantum groups, with a factorizable R-matrix. Our main purpose is to obtain non-semisimple modular tensor categories for quantum groups at even roots of unity, where typically the initial representation category is not even braided. Our quasi-Hopf algebras are built from modules over the twisted Drinfeld double via a universal construction, but we also work out explicit generators and relations, and we prove that these algebras are modularizations of the quantum group extensions with R-matrices listed in [LO17]. As an application, we find one distinguished factorizable quasi-Hopf algebra for any finite root system and any root of unity of even order (resp. divisible by 4 or 6, depending on the root length). Under the same divisibility condition on a rescaled root lattice, a corresponding lattice Vertex-Operator Algebra contains a VOA W defined as the kernel of screening operators. We then conjecture that W representation categories are braided equivalent to the representation categories of the distinguished factorizable quasi-Hopf algebras. For A_1 root system, our construction specializes to the quasi-Hopf algebras in [GR17b, CGR17], where the answer is affirmative, similiary for B_n at fourth root of unity in [FGR17b, FL17].

Keywords

Cite

@article{arxiv.1809.02116,
  title  = {Modularization of small quantum groups},
  author = {Azat M. Gainutdinov and Simon Lentner and Tobias Ohrmann},
  journal= {arXiv preprint arXiv:1809.02116},
  year   = {2018}
}

Comments

64 pages; v2: Acknowledgments and Example 7.4 completed

R2 v1 2026-06-23T03:57:01.732Z