Colloquium: "Functional methods in QFT and renormalization, part II" by Dr. Riccardo Martini

Speaker: Dr. Martini is a member of this unit (check his page).

Abstract. In this lecture we introduce the effective action. This functional plays for the quantum (statistical) theory a role similar to the one represented by the action for the classical theory. The effective action takes into account the contribution of all the fluctuations and radiative corrections. It also generates the 1PI Feynman graphs from which we can construct all the correlators of the theory. After defining the effective action and investigating its relation to other functionals, we will inspect its perturbative expansion and the Feynman graphs it generates.