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SUMMARY:Shadows and Soft Exchange in Celestial CFT - Daniel Kapec\, Harvar
 d University
DTSTART:20211117T141500Z
DTEND:20211117T151500Z
UID:TALK164446@talks.cam.ac.uk
CONTACT:104116
DESCRIPTION:I will discuss exponentiated soft exchange in (d+2)-dimensiona
 l gauge and gravitational theories using the celestial CFT formalism. Thes
 e models exhibit spontaneously broken asymptotic symmetries generated by g
 auge transformations with non-compact support\, and the effective dynamics
  of the associated Goldstone “edge” mode is expected to be d-dimension
 al. The introduction of an infrared regulator also explicitly breaks these
  symmetries so the edge mode in the regulated theory is really a d-dimensi
 onal pseudo-Goldstone boson. Symmetry considerations determine the leading
  terms in the effective action\, whose coefficients are controlled by the 
 infrared cutoff. Computations in this model reproduce the abelian infrared
  divergences in d=2\, and capture the re-summed (infrared finite) soft exc
 hange in higher dimensions. The model also reproduces the leading soft the
 orems in gauge and gravitational theories in all dimensions. Interestingly
 \, we find that it is the shadow transform of the Goldstone mode that has 
 local d-dimensional dynamics: the effective action expressed in terms of t
 he Goldstone mode is non-local for d>2. The analysis demonstrates that sym
 metry principles suffice to calculate soft exchange in gauge theory and gr
 avity.
LOCATION:ONLINE - Details to be sent by email
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