Pierre Clavier (Potsdam)
Most physical quantities of quantum field theory (QFT can only be computed via a perturbative approach, i.e. a formal series.
A natural question is how to assign an analytic function to this formal series, and what is its analyticity domain.
Based on physical arguments, we will see why series summation and Borel resummation are not good candidates, while Borel-Ecalle resummation is.