logo Instantons from quaternionic geometry

I discuss instanton corrections to the hypermultiplet moduli space of string compactifications on a Calabi-Yau threefold.
I concentrate on the particular case of the universal hypermultiplet where the corrections can be encoded by a single function characterizing a generic four-dimensional quaternion-Kähler manifold.
I present explicit solutions for this function describing all one-instanton corrections, including the fluctuations around the instanton to all orders in the string coupling constant.