Remote Nordic HET seminar: Rodolfo Panerai

Speaker: Rodolfo Panerai

Title: Exact TTbar-deformation of two-dimensional Yang-Mills theory

Abstract: In this talk, I will discuss the TTbar deformation of two-dimensional Yang-Mills theory on the sphere. Focusing on unitary gauge groups, I will show how the deformed partition function can be obtained by solving the relevant flow equation at the level of individual monopole sectors. For positive values of the deformation parameter, the quantum spectrum of the theory experiences a truncation, the partition function reducing to a sum over a finite set of energy states. For negative values, instead, the appearance of non-perturbative contributions drastically modifies the structure of the partition function, regularising its naive divergences and seemingly breaking locality. In the large-N expansion, the theory exhibits a rich phase diagram. The transitions between different phases are driven by instantons both in the 't Hooft coupling (leading to a deformed Douglas-Kazakov phase transition) and in the deformation parameter.