Almost everywhere convergence of Bochner--Riesz means for the twisted Laplacian

Let $\mathcal L$ denote the twisted Laplacian in $\mathbb C^d$. We study almost everywhere convergence of the Bochner--Riesz mean $S^\delta_{t}(\mathcal L) f$ of $f\in L^p(\mathbb C^d)$ as $t\to \infty$, which is an expansion of $f$ in the special Hermite functions. For $2\le p\le \infty$, we obtain the sharp range of the summability indices $\delta$ for which the convergence of $S^\delta_{t}(\mathcal L) f$ holds for all $f\in L^p(\mathbb C^d)$.