School of Mathematics Colloquium

Unitarity of the KZ/Hitchin connection on conformal blocks in genus 0

by Prof. Prakash Belkale (University of North Carolina, USA)

Thursday, August 4, 2011 from to (Asia/Kolkata)
at Colaba Campus ( AG-69 )
Description
Associated to a (finite dimensional, simple) Lie algebra, and
a finite set of irreducible representations (and a level), there are vector
bundles of conformal blocks on  suitable moduli spaces of curves with marked
points. These conformal block bundles carry  flat projective connections
(KZ/Hitchin).

We prove that conformal block bundles in genus zero (for arbitrary simple
Lie algebras) carry geometrically defined unitary metrics (of
Hodge-theoretic origin, as conjectured by  Gawedzki) which are preserved
by  the KZ/Hitchin connection. Our proof builds upon the work of  Ramadas
who proved this unitarity statement in the case of the Lie algebra sl(2)
(and  genus zero).