Tate module tensor decompositions and the Sato-Tate conjecture for certain abelian varieties potentially of ${\mathrm{GL}}_2$-type

Abstract

We introduce a tensor decomposition of the $\ell$-adic Tate module of an abelian variety $A_0$ defined over a number field which is geometrically isotypic. If $A_0$ is potentially of $\GL_2$-type and defined over a totally real number field, we use this decomposition to describe its Sato--Tate group and to prove the Sato--Tate conjecture in certain cases.

Minor changes. To appear in Math. Zeit