Aula Conversi (Dipartimento di Fisica - Ed. G. Marconi)
Aula Conversi
Dipartimento di Fisica - Ed. G. Marconi
Description
Perturbative series in quantum mechanics and quantum field theory are known to be only asymptotic and generically require the inclusion of extra contributions non-perturbative in the coupling, such as instantons, to reproduce exact results. Using a geometrical approach based on the Picard-Lefschetz theory and Borel resummation methods, we show how exact results can be encoded in a modified perturbative series in a class of quantum mechanical systems. There is no need of transseries, i.e. non perturbative effects, such as real (or complex) instantons. Applications are presented and perspectives for quantum field theories are shortly discussed
