Cubic surfaces and cubic threefolds, Jacobians and intermediate Jacobians

Abstract

In this paper we study principally polarized Abelian varieties that admit an automorphism of order 3. It turns out that certain natural conditions on the multiplicities of its action on the differentials of the first kind guarantee that those polarized varieties are not Jacobians of curves. As an application, we get another proof of the (already known) fact that intermediate Jacobians of certain cubic threefolds are not Jacobians of curves.