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SUMMARY:Towards the exact de Sitter S-matrix of the Principal Chiral Model
  - Ian Morrison (DAMTP)
DTSTART:20130524T120000Z
DTEND:20130524T130000Z
UID:TALK44526@talks.cam.ac.uk
CONTACT:Dr Joan Camps
DESCRIPTION:In Minkowski space the S-matrix in an invaluable tool for anal
 ysing quantum field theories. Scattering matrices may also be constructed 
 and exploited in eternally inflating spacetimes. In the first part of this
  talk I will review the perturbative construction of the S-matrix in globa
 l de Siter space. I will emphasize it’s value as a gauge and field redef
 inition-invariant probe for QFTs in the inflationary setting. As time allo
 ws I will also discuss features of such QFTs which\, while obscure from th
 e vantage point of local correlation functions\, are transparent when view
 ed through the S-matrix.\n\nIn the second part of my talk I will discuss r
 ecent progress towards constructing the exact S-matrix of the Principal Ch
 iral Model (PCM) in de Sitter space. The PCM is a 2-dimensional non-linear
  sigma model endowed with many of the mature attributes of QCD\, including
  asymptotic freedom and dimensional transmutation. The PCM also contains a
 n infinite number of hidden symmetries which make the theory integrable in
  Minkowski space. A sufficient number of these symmetries exist also in th
 e de Sitter theory\, and thus the de Sitter S-matrix may be determined up 
 to a CDD-type ambiguity.
LOCATION:Pavilion B Potter Room (B1.19)
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