## Journal of Differential Geometry

- J. Differential Geom.
- Volume 92, Number 1 (2012), 71-151.

### Stability of Hodge bundles and a numerical characterization of Shimura varieties

Martin Möller, Eckart Viehweg, and Kang Zuo

#### Abstract

Let $U$ be a connected non-singular quasi-projective variety and $f : A \to U$ a family of abelian varieties of dimension $g$. Suppose that the induced map $U \to \mathcal{A}_g$ is generically finite and there is a compactification $Y$ with complement $S = Y \backslash U$ a normal crossing divisor such that $\Omega_Y^1 (\log S)$ is nef and $\omega_Y (S)$ is ample with respect to $U.

We characterize whether $U$ is a Shimura variety by numerical data attached to the variation of Hodge structures, rather than by properties of the map $U \to \mathcal{A}_g$ or by the existence of CM points.

More precisely, we show that $f : A \to U$ is a Kuga fibre space, if and only if two conditions hold. First, each irreducible local subsystem $\mathbb{V}$ of $R_1 f_* \mathbb{C}_A$ is either unitary or satisfies the Arakelov equality. Second, for each factor $M$ in the universal cover of $U$ whose tangent bundle behaves like that of a complex ball, an iterated Kodaira-Spencer map associated with $V$ has minimal possible length in the direction of $M$. If in addition $f : A \to U$ is rigid, it is a connected Shimura subvariety of $\mathcal{A}_g$ of Hodge type.

#### Article information

**Source**

J. Differential Geom., Volume 92, Number 1 (2012), 71-151.

**Dates**

First available in Project Euclid: 6 November 2012

**Permanent link to this document**

https://projecteuclid.org/euclid.jdg/1352211224

**Digital Object Identifier**

doi:10.4310/jdg/1352211224

**Mathematical Reviews number (MathSciNet)**

MR3003876

**Zentralblatt MATH identifier**

06130614

#### Citation

Möller, Martin; Viehweg, Eckart; Zuo, Kang. Stability of Hodge bundles and a numerical characterization of Shimura varieties. J. Differential Geom. 92 (2012), no. 1, 71--151. doi:10.4310/jdg/1352211224. https://projecteuclid.org/euclid.jdg/1352211224