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SUMMARY:On the physical meaning and consequences of the loop IR divergence
 s in global dS - Emil Akhmedov (ITEP)
DTSTART:20130124T130000Z
DTEND:20130124T140000Z
UID:TALK43111@talks.cam.ac.uk
CONTACT:Dr Dorigoni
DESCRIPTION: The tak is based on arXiv:1209.4448\, arXiv:1202.1202 and arX
 iv:1110.2257. We show that in global de Sitter space its isometry is broke
 n by the loop IR divergences for any invariant vacuum state of the massive
  scalars. We derive kinetic equation in global de Sitter space. It follows
  from the Dyson-Schwinger equation of the Schwinger-Keldysh diagrammatic t
 echnique in IR limit and allows to understand the physical meaning and con
 sequences of the loop IR divergences. In many respects the isometry breaki
 ng in global dS is similar to the one in the contracting Poincare patch of
  de Sitter space. Hence\, as a warm up exercise we study the kinetic equat
 ion and properties of its solutions in the expanding and contracting Poinc
 are patches of de Sitter space. Quite unexpectedly we find that under some
  initial conditions there is an explosive production of massive particles 
 in the expanding Poincare patch.
LOCATION:Potter Room (first floor\, Pav. B)
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