BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Marcos Marino (Geneva) DTSTART:20210914T080000Z DTEND:20210914T090000Z DTSTAMP:20260423T021041Z UID:Sem21/1 DESCRIPTION:Title: Re surgence and renormalons in quantum field theory\nby Marcos Marino (Ge neva) as part of SEU Yau Center Theoretical Physics Seminars 2021\n\n\nAbs tract\nPerturbation theory remains the most general approach to understand ing generic quantum theories. However\, the series obtained in this way ar e usually divergent and need to be complemented by additional\, non-pertur bative information. The theory of resurgence is a framework to make sense of divergent series by using resummation techniques and including non-pert urbative information in the form of “trans-series". In quantum mechanics \, many observables can be fully understood by using the theory of resurge nce\, but quantum field theories are more challenging. In realistic quantu m field theories\, the main source of non-perturbative corrections to the perturbative series are the so-called renormalons\, which remain mysteriou s objects. In this talk I will present the basics of the theory of resurge nce and some successful applications in quantum mechanics. I will then mov e to quantum field theories. In order to address the problems due to renor malons\, I will focus on integrable\, asymptotically free theories in two dimensions where one can make very explicit analysis. I will show in concr ete examples that observables can be computed by trans-series due to renor malons\, and I will discuss more generally the virtues and limits of the r esurgent approach.\n LOCATION:https://researchseminars.org/talk/Sem21/1/ END:VEVENT END:VCALENDAR