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SUMMARY:Large-Field and Open EFTs\, Decoherence and Inflation - Cliff Burg
 ess (Perimeter Institute)
DTSTART:20141013T120000Z
DTEND:20141013T130000Z
UID:TALK55365@talks.cam.ac.uk
CONTACT:33215
DESCRIPTION:Effective field theories (EFTs) usefully exploit the simplicit
 y that follows from a hierarchy of scales\, and provide the framework that
  justifies controlled semiclassical calculations with gravity. Inflation r
 aises two conceptual questions for EFTs: What controls EFTs when fields ar
 e larger than the Planck scale? and What is the EFT governing extra-Hubble
  physics during inflation? This talks provides answers to both questions. 
 Pseudo-Goldstone bosons are used as examples of controlled large-field EFT
 s\, with the message being that these can lead to more general potentials 
 than the usual trigonometric ones. It is argued that the EFT describing ex
 tra-Hubble physics exists\, but is not capturable in terms of an effective
  lagrangian. The proposed EFT explains why primordial quantum fluctuations
  quickly decohere while outside the Hubble scale\, re-entering as classica
 l fluctuations in the field eigen-basis. It also explains why fluctuation 
 probabilities are described by Starobinsky's stochastic framework\, and pr
 ovides a first-principles derivation of it (plus\, in principle\, its lead
 ing sub-dominant corrections).
LOCATION:CMS\, Pav. B\, CTC Common Room (B1.19) [Potter Room]
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