Characterizing rational homogeneous spaces via $\mathbb{C}^*$-actions

Abstract

We study smooth varieties of Picard number one admitting a special dominating family of rational curves and an equalized $\mathbb{C}^*$-action. In particular we show that $X$ is a smooth variety of Picard number one with nef tangent bundle admitting an equalized $\mathbb{C}^*$-action with an isolated extremal fixed point if and only if $X$ is an irreducible Hermitian symmetric space.