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SUMMARY:Manifest gauge invariance and old-fashioned perturbation theory
DTSTART:20260422T090000Z
DTEND:20260422T103000Z
DTSTAMP:20260426T062300Z
UID:indico-event-2541@indico.ifae.es
DESCRIPTION:Speakers: Ryan Daniel Plestid\n\n\nWhen dealing with bound sta
 tes (e.g.\, atoms or nuclei) many calculations are most efficiently carrie
 d out using old-fashioned perturbation theory. \nIt is difficult\, howeve
 r\, to see how gauge invariance manifests at the level of the amplitude (t
 his is related to the non-conservation of energy in OFPT). \nIn this talk
  I will explain how a partial-fraction trick can reorganize amplitudes int
 o a form that is manifestly gauge invariant. Remarkably\, when applied to
  \nthe Compton tensor\, the resulting amplitude decomposes into four sepa
 rate gauge invariant pieces that are naturally organized around a heavy-ma
 ss \nexpansion. \n\n \n\nhttps://indico.ifae.es/event/2541/
LOCATION:IFAE Seminar Room (In-Person)
URL:https://indico.ifae.es/event/2541/
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