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SUMMARY:Claudia de Rham (Imperial College)
DTSTART:20200918T170000Z
DTEND:20200918T180000Z
DTSTAMP:20260423T022809Z
UID:CMU-TP/12
DESCRIPTION:Title: <a href="https://researchseminars.org/talk/CMU-TP/12/">
 Causality and Positivity with Gravity</a>\nby Claudia de Rham (Imperial Co
 llege) as part of Carnegie Mellon theoretical physics\n\n\nAbstract\nI wil
 l investigate the propagation of gravitational waves on curved spacetimes 
 within the low energy effective field theory of gravity\, where effects fr
 om heavy fields are captured by higher dimensional curvature operators. De
 pending on the spin of the particles integrated out\, the speed of gravita
 tional waves at low energy can be either superluminal or subluminal as com
 pared to the causal structure observed by other species. I will clarify wh
 y a mild level of superluminality is not in contradiction with causality\,
  analyticity or Lorentz invariance and show how consistent gravitational l
 ow energy effective theories can self-protect by ensuring that any time ad
 vance and superluminality calculated within the regime of validity of the 
 effective theory is necessarily unresolvable for such theories. These cons
 iderations are particularly relevant for putting constraints on cosmologic
 al and gravitational effective field theories and I will provide explicit 
 criteria to be satisfied so as to ensure causality.\n
LOCATION:https://researchseminars.org/talk/CMU-TP/12/
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