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SUMMARY:Scattering Amplitudes and Worldsheet Models of QFTs
DTSTART:20170213T140000
DTEND:20170213T153000
DTSTAMP:20260531T005142Z
UID:20232b16d1b4ecb65ad57097274c8417363233d4b29f4baf0f03d7ee
CATEGORIES:Conferences - Seminars
DESCRIPTION:Ricardo Monteiro\nI will describe recent progress on the study
  of scattering amplitudes via ambitwistor strings and the scattering equat
 ions. Ambitwistor strings are worldsheet models of quantum field theories\
 , inspired by string theory. They naturally lead to a representation of am
 plitudes based on the scattering equations. While worldsheet models and re
 lated ideas have had a wide-ranging impact on the modern study of amplitud
 es\, their direct application at loop level is a very recent success. I wi
 ll show how a major difficulty in the loop-level story\, the technicalitie
 s of higher-genus Riemann surfaces\, can be avoided by turning the higher-
 genus surface into a nodal Riemann sphere\, with the nodes representing th
 e loop momenta. I will present new formulas for the one-loop integrands of
  gauge theory and gravity\, with or without supersymmetry\, and also some 
 two-loop results
LOCATION:BSP 727 https://plan.epfl.ch/?room==BSP%20727
STATUS:CONFIRMED
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