Renormalized Reshetikhin-Turaev invariants for the unrolled quantum group of ${\mathfrak{sl}}_2(\mathbb{C})$

Abstract

This paper is a self-contained introduction to the theory of renormalized Reshetikhin-Turaev invariants of links defined by Geer, Patureau-Mirand and Turaev. Whereas the standard Reshetikhin-Turaev theory of a $\mathbb{C}$-linear ribbon category assigns the trivial invariant to any link with a component colored by a simple object of vanishing quantum dimension, the renormalized theory does not. We give a streamlined development of the renormalized Reshetikhin-Turaev theory of links for the category of weight modules over the restricted unrolled quantum group of ${\mathfrak{sl}}_2(\mathbb{C})$ at an even root of unity.

30 pages