Exact Results for ’t Hooft Loops in Gauge Theories on a four-sphere

by Takuya Okuda (University of Tokyo)

Tuesday 11 Jan 2011, 14:00 → 15:00 Europe/Zurich

TH Theory Conference Room (CERN)

Path-integrals in N=2 supersymmetric gauge theories on S^4 are exactly evaluated in the presence of a 't Hooft loop operator. A 't Hooft loop represents the worldline of an infinitely heavy monopole, and is defined by a singular Dirac monopole background around which the field fluctuations are integrated over. We use the localization techniques to perform the calculations for 't Hooft loops, which are more subtle than Wilson loops due to the singularities in the fields. Our gauge theory calculations successfully confirm the predictions for 't Hooft loops given by two-dimensional conformal field theories via the AGT correspondence.