A quantization of the $\operatorname{SL}_2(\mathbb{C})$-Chern-Simons invariant of tangle exteriors

Calvin McPhail-Snyder

Published: 2025/9/2

Abstract

Previous work of the author and Reshetikhin shows how to use modules over the unrestricted quantum group (at a root of unity) to define quantum representations of a groupoid of braids with flat $\mathfrak{sl}_{2}$ connections on their complements, equivalently $\operatorname{SL}_{2}(\mathbb{C})$ representations or hyperbolic structures. In this article we explain how to use these representations to define quantum invariants $\mathcal{Z}_{N}$ of tangles and links with such geometric structures. Unlike previous constructions of geometric quantum invariants $\mathcal{Z}_{N}$ is defined without any phase ambiguity. We interpret $\mathcal{Z}_{N}$ as a quantization of the $\operatorname{SL}_{2}(\mathbb{C})$-Chern-Simons invariant $\mathcal{I}$. It is natural to conjecture that $\mathcal{Z}_{N}$ is related to the quantization of Chern-Simons theory with complex, noncompact gauge group $\operatorname{SL}_{2}(\mathbb{C})$ and we discuss how to interpret our results in this context.

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