Monodromy Groups of Supersingular Abelian Surfaces over $\mathbb{Q}_p$

Abstract

For primes $p\ge 7$, we give a parametrization of the filtered $φ$-modules attached to the $p$-adic Tate modules of abelian surfaces over $\mathbb{Q}_p$ with supersingular good reduction. We use this classification to determine the neutral components of the monodromy groups of the associated $p$-adic representations up to $\bar{\mathbb{Q}}_p$-isomorphism. Furthermore, we analyze the $p$-adic distribution of these groups in the moduli space of filtered $φ$-modules. In particular, we prove that the neutral components are generically isomorphic to $\mathbf{GL}_2 \times_{\det} \mathbf{GL}_2$.