Crystalline lifts of semisimple $G$-valued Galois representations with fixed determinant

Abstract

For a finite extension $K/\mathbb{Q}_p$ and a split reductive group $G$ over $\mathcal{O}_K$, let $\overline{\rho} \colon \mathrm{Gal}_K \to G(\overline{\mathbb{F}}_p)$ be a continuous quasi-semisimple mod $p$ $G$-valued representation of the absolute Galois group $\mathrm{Gal}_K$. Let $\overline{\rho}^{\mathrm{ab}}$ be the abelianization of $\overline{\rho}$ and fix a crystalline lift $\psi$ of $\overline{\rho}^{\mathrm{ab}}$. We show the existence of a crystalline lift $\rho$ of $\overline{\rho}$ with regular Hodge-Tate weights such that the abelianization of $\rho$ coincides with $\psi$. We also show analogous results in the case that $G$ is a quasi-split tame group and $\overline{\rho} \colon \mathrm{Gal}_K \to {^L}G(\overline{\mathbb{F}}_p)$ is a semisimple mod $p$ $L$-parameter. These theorems are generalizations of those of Lin and B\"ockle-Iyengar-Pa\v{s}k\={u}nas.