Homogeneous Ulrich bundles on homogenous varieties of certain exceptional types

This paper studies the Ulrich property of homogeneous vector bundles on rational homogeneous varieties. We provide a criterion for an initialized irreducible homogeneous vector bundle on a rational homogeneous variety with any Picard number to be Ulrich with respect to any polarizations. This criterion extends Fonarev's result for rational homogeneous varieties with Picard number one. As an application, we show that rational homogeneous varieties with Picard number at least two of certain exceptional algebraic groups do not admit such homogeneous Ulrich bundles with respect to the minimal ample class.