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SUMMARY:The no-boundary wave function 2.0 - Thomas Hertog (Leuven)
DTSTART:20241129T130000Z
DTEND:20241129T140000Z
UID:TALK223564@talks.cam.ac.uk
CONTACT:Daniela Cors
DESCRIPTION:I discuss some of the fundamentals of the Hartle-Hawking no-bo
 undary wave function and what it predicts for our cosmological observation
 s. First\, I show that the fluctuation convergence criterion recently revi
 ved by Kontsevich\, Segal and Witten\, when applied to complex no-boundary
  saddles\, acts as an inflaton selection mechanism that effectively bounds
  the tensor-to-scalar ratio of CMB fluctuations to be less than 0.08\, in 
 line with current observations. Second\, I show that the conditioning and 
 coarse-graining needed to extract predictions for local observations in th
 e no-boundary state induce a Page-like transition that tilts the probabili
 ty distribution towards a large number of inflationary efolds. Finally\, I
  present a holographic formulation of the wave function that\, I conjectur
 e\, may be a stepping stone to define the theory beyond the semiclassical 
 approximation. Evidence in favor of this comes from a calculation of the q
 uantum corrections to the entropy of de Sitter space computed using the Ad
 S/CFT correspondence. 
LOCATION:Potter room / https://cam-ac-uk.zoom.us/j/82964888415?pwd=SjksibD
 mS3OFLVd59XQ5uwoVJlRNrD.1
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