SESZIONE DI TORINO
I will discuss euclidean D-brane instanton non- perturbative effects on string compactifications, and focus on their dependence on the compactification moduli. An important phenomenon is the change in the set of BPS instantons as one moves in moduli space of CY compactifications, due to walls of marginal stability where some instantons become unstable and decay. The holomorphic moduli dependence dictated by supersymmetry is recovered by taking into account contributions from simultaneous multiple instantons. We also discuss additional phenomena related to the generation of non- perturbative multi-fermion F-terms, and their role in flux compactifications.

DATA: 25-11-2008