BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Gabriel Cuomo (EPFL) DTSTART:20200601T183000Z DTEND:20200601T193000Z DTSTAMP:20260423T024726Z UID:Kadanoff/4 DESCRIPTION:Title: The epsilon expansion meets semiclassics\nby Gabriel Cuomo (EPFL) as part of Kadanoff seminars\n\n\nAbstract\nIn this talk\, I will study the s caling dimension of the lightest operator of charge n in the U(1) model at the Wilson-Fisher fixed point in 4-ε dimensions.\nEven for a perturbativ ely small fixed point coupling λ\, standard perturbation theory breaks do wn for sufficiently large λ n. Treating λ n as fixed for small λ\, I wi ll show that the scaling dimension can be successfully computed through a semiclassical expansion around a non-trivial trajectory\, resulting in a s eries in the coupling whose coefficients are fixed functions of λ n. I wi ll discuss explicitly the computation of the first two orders in the expan sion. The result\, when expanded at small λ n\, perfectly agrees with all available diagrammatic computations. The asymptotic at large λ n reprodu ces the systematic large charge expansion\, recently derived in CFT.\nSimi lar results can be derived in the U(1) model in 3-ε dimensions. I will br iefly comment on the application of similar ideas in the calculation of ot her observables\, such as three-point functions of charged operators. This talk is based on https://arxiv.org/abs/1909.01269 and https://arxiv.org/a bs/1911.08505.\n LOCATION:https://researchseminars.org/talk/Kadanoff/4/ END:VEVENT END:VCALENDAR