A proof of Witten's asymptotic expansion conjecture for WRT invariants of Seifert fibered homology spheres

Abstract

Let $X$ be a general Seifert fibered integral homology $3$-sphere with $r\ge 3$ exceptional fibers. For every root of unity $\hat{I}\P \ne 1$, we show that the SU(2) WRT invariant of $X$ evaluated at $\hat{I}\P$ is (up to an elementary factor) the non-tangential limit at $\hat{I}\P$ of the GPPV invariant of $X$, thereby generalizing a result from [Andersen-Mistegard 2022]. Based on this result, we apply the quantum modularity results developed in [Han-Li-Sauzin-Sun 2023] to the GPPV invariant of $X$ to prove Witten's asymptotic expansion conjecture [Witten 1989] for the WRT invariant of $X$. We also prove that the GPPV invariant of $X$ induces a higher depth strong quantum modular form. Moreover, when suitably normalized, the GPPV invariant provides an ``analytic incarnation'' of the Habiro invariant.

68 pages