English

Direct Images in Non Abelian Hodge Theory

Algebraic Geometry 2016-12-21 v1 Differential Geometry

Abstract

In this paper we explain how non-abelian Hodge theory allows one to compute the L2L^2 cohomology or middle perversity higher direct images of harmonic bundles and twistor D-modules in a purely algebraic manner. Our main result is a new algebraic description for the fiberwise L2L^2 cohomology of a tame harmonic bundle or the corre- sponding flat bundle or tame polystable parabolic Higgs bundle. Specifically we give a formula for the Dolbeault version of the L2L^2 pushforward in terms of a modification of the Dolbeault complex of a Higgs bundle which takes into account the monodromy weight filtration in the normal directions of the horizontal parabolic divisor. The parabolic structure of the higher direct image is obtained by analyzing the V -filtration at a normal crossings point. We prove this algebraic formula for semistable families of curves.

Keywords

Cite

@article{arxiv.1612.06388,
  title  = {Direct Images in Non Abelian Hodge Theory},
  author = {R. Donagi and T. Pantev and C. Simpson},
  journal= {arXiv preprint arXiv:1612.06388},
  year   = {2016}
}