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SUMMARY:Resonant resurgent asymptotics from quantum field theory - Michael
  Borinsky (ETH Zürich)
DTSTART:20220913T133000Z
DTEND:20220913T143000Z
UID:TALK178112@talks.cam.ac.uk
DESCRIPTION:The factorial divergence of perturbative expansions is believe
 d to be governed by two seemingly unrelated phenomena: Instantons that ari
 se due to nontrivial solutions of the classical field equations and renorm
 alons that appear due to a factorially growing contribution from the renor
 malization subtraction terms of a family of Feynman diagrams.&nbsp\; I wil
 l report on joint work with David Broadhurst\, Gerald Dunne and Max Meynig
  in which a particularly interesting renormalon in phi^3 theory was analyz
 ed using tools from Ecalle's resurgence framework. A recent work with Davi
 d Broadhurst revealed the intricate role of 'resonant' logarithmic terms f
 or this renormalon and allowed an all-trans-series-order resurgence analys
 is. The overall shape of our all-order trans-series solution and our (well
 -tested) conjectured formulas for the asymptotic behaviour of the trans-se
 ries coefficients hint at the existence of a reality cancellation mechanis
 m as it is observed in quantum mechanical instanton computations. (Based o
 n https://arxiv.org/abs/2202.01513 )
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