Pluriharmonic maps into buildings and symmetric differentials

Abstract

Given a complex smooth quasi-projective variety $X$, a semisimple algebraic group $G$ defined over some non-archimedean local field $K$ and a Zariski dense representation $\varrho :{\pi }_1(X)\to G(K)$, we construct a $\varrho$-equivariant (pluri-)harmonic map from the universal cover of $X$ into the Bruhat-Tits building $\Delta (G)$ of $G$, with some suitable asymptotic behavior. This theorem generalizes the previous work by Gromov-Schoen to the quasi-projective setting. As an application, we prove that $X$ has nonzero global logarithmic symmetric differentials if there exists a linear representation ${\pi }_1(X)\to {\mathrm{GL}}_N(\mathbb{K})$ with infinite image, where $\mathbb{K}$ is any field. This theorem generalizes the previous work by Brunebarbe, Klingler and Totaro to the quasi-projective setting.

53 pages. V2: Major revision, more self-contained and main results improved. V3: title changed; v4: exposition improved

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