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SUMMARY:Rigorous bounds on Einstein--Maxwell theory and the Black Hole Wea
 k Gravity Conjecture - Johan Henriksson (Pisa)
DTSTART:20220505T120000Z
DTEND:20220505T130000Z
UID:TALK173270@talks.cam.ac.uk
CONTACT:Chiung Hwang
DESCRIPTION:In this talk I will discuss positivity bounds on the effective
  field theory (EFT) of photons\, derived from dispersion relations and the
  generalised optical theorem. In general\, basic assumptions on the high-e
 nergy UV completion\, such as unitarity and partial wave decomposition\, i
 mply bounds on the space of the Wilson coefficients parametrising the low-
 energy EFT. We develop a method that allows us to bound Wilson coefficient
 s appearing in amplitudes of all possible polarisations\, not just the for
 ward amplitudes. In the absence of dynamical gravity\, such bounds imply a
  set of inequalities known as the Black Hole Weak Gravity Conjecture (WGC)
 . However\, in the presence of dynamical gravity\, we find that the disper
 sion relation argument alone cannot rule out a small violations of the Bla
 ck Hole WGC\, and we determine the maximum allowed size of such violations
 .
LOCATION:Potter Room\, DAMTP
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