English

Cleft Extensions and Quotients of Twisted Quantum Doubles

Quantum Algebra 2015-11-10 v1 High Energy Physics - Theory Group Theory Rings and Algebras Representation Theory

Abstract

Given a pair of finite groups F,GF, G and a normalized 3-cocycle ω\omega of GG, where FF acts on GG as automorphisms, we consider quasi-Hopf algebras defined as a cleft extension kωG#ckF\Bbbk^G_\omega\#_c\,\Bbbk F where cc denotes some suitable cohomological data. When FF:=F/AF\rightarrow \overline{F}:=F/A is a quotient of FF by a central subgroup AA acting trivially on GG, we give necessary and sufficient conditions for the existence of a surjection of quasi-Hopf algebras and cleft extensions of the type kωG#ckFkωG#ckF\Bbbk^G_\omega\#_c\, \Bbbk F\rightarrow \Bbbk^G_\omega\#_{\overline{c}} \, \Bbbk \overline{F}. Our construction is particularly natural when F=GF=G acts on GG by conjugation, and kωG#ckG\Bbbk^G_\omega\#_c \Bbbk G is a twisted quantum double Dω(G)D^{\omega}(G). In this case, we give necessary and sufficient conditions that Rep(kωG#ckG\Bbbk^G_\omega\#_{\overline{c}} \, \Bbbk \overline{G}) is a modular tensor category.

Keywords

Cite

@article{arxiv.1404.2016,
  title  = {Cleft Extensions and Quotients of Twisted Quantum Doubles},
  author = {Geoffrey Mason and Siu-Hung Ng},
  journal= {arXiv preprint arXiv:1404.2016},
  year   = {2015}
}

Comments

LaTex; 14 pages

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