Character varieties and harmonic maps to R-trees

Abstract

We show that the Korevaar-Schoen limit of the sequence of equivariant harmonic maps corresponding to a sequence of irreducible $S{L}_2(\mathbb{C})$ representations of the fundamental group of a compact Riemannian manifold is an equivariant harmonic map to an $\mathbb{R}$-tree which is minimal and whose length function is projectively equivalent to the Morgan-Shalen limit of the sequence of representations. We then examine the implications of the existence of a harmonic map when the action on the tree fixes an end.

12 pages. Latex. to appear in Math. Res. Lett