Informal High Energy Theory Seminar

It will be argued that essentially all the deep concepts of perturbative quantum field theory could have been discovered in non-quantum (classical) field theories. These include Feynman diagrams, effective actions, divergences, regularization, renormalization and field doubling (the Closed Time Path formalism). The central case study will be the Effective Field Theory approach to General Relativity, more specifically to the post-Newtonian two-body problem. A non-relativistic decomposition of Einstein's field will be central. Time permitting, we shall describe equivalent periodic sources - a novel geometric decomposition of the quasi-periodic motion of a trajectory around a black hole in the context of the self force and the extreme mass ratio approximation.