Speaker
Marialuisa Frau
(TO)
Description
We study the non-perturbative behaviour of superconformal gauge theories
with rigid N=2 supersymmetry in four dimensions, in particular N=2*
theories, in presence of two-dimensional defects and discuss the
relation between their S-duality properties and the possibility of
computing exact quantum observables. For these theories, the
prepotential and the twisted chiral superpotential, that encode
respectively the four and two-dimensional low-energy effective dynamics
on the Coulomb branch of moduli space, obey a modular anomaly equation
whose validity is related to S-duality. This fact allow one to write
them in terms of (quasi)-modular forms, thus resumming all instanton
contributions. The results can be checked against the microscopic
multi-instanton calculus and the chiral ring equations of the quiver
theories associated to the coupled 2d/4d systems.
