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SUMMARY:Symmetries of Inflation - Valentin Assassi (DAMTP)
DTSTART:20130211T130000Z
DTEND:20130211T140000Z
UID:TALK43308@talks.cam.ac.uk
CONTACT:Camille Bonvin
DESCRIPTION:During inflation\, time translations are spontaneously broken 
 by the time-dependent matter field. As a result\, the conformal symmetries
  of de Sitter are spontaneously broken and curvature perturbations can be 
 identified with the ``Goldstone boson'' associated with this symmetry brea
 king.  Taking this point of view\, I will explain how the low-momentum phy
 sics of curvature perturbations are constrained by symmetries. I will focu
 s the discussion on two aspects. First\, I will show how symmetries force 
 curvature perturbations to freeze on super-horizon scales at all orders in
  a loop expansion. I will then explain how soft limits of inflationary cor
 relation functions can be derived in a model-independent way using Ward id
 entities. In particular\, this approach makes manifest how these soft limi
 ts are sensitive to the number of light particles during inflation.
LOCATION:CMS\, Pav.B\, CTC Common Room (B1.19)
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