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Title: Effect of intermediate Minkowskian evolution on CMB bispectrum

We consider a non-inflationary early Universe scenario in which relevant scalar perturbations get frozen out at some point, but then are defrosted and follow a long nearly Minkowskian evolution before the hot era. This intermediate stage leaves specific imprint on the CMB 3-point function, largely independent of details of microscopic physics. In particular, the CMB bispectrum undergoes oscillations in the multipole l space with roughly constant amplitude. The latter is in contrast to the oscillatory bispectrum enhanced in the flattened triangle limit, as predicted by inflation with non-Bunch-Davies vacuum. Given this and other peculiar features of the bispectrum, stringent constraints imposed by the Planck data may not apply. The CMB 3-point function is suppressed by the inverse duration squared of the Minkowskian evolution, but can be of observable size for relatively short intermediate Minkowskian stage.
Authors:
;  [1] ;  [2]
  1. Institute for Nuclear Research of the Russian Academy of Sciences, 60th October Anniversary Prospect 7a, 117312, Moscow (Russian Federation)
  2. Service de Physique Théorique, Université Libre de Bruxelles (ULB), CP225 Boulevard du Triomphe, B-1050 Bruxelles (Belgium)
Publication Date:
OSTI Identifier:
22373662
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2014; Journal Issue: 04; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; AMPLITUDES; COSMOLOGICAL INFLATION; FUNCTIONS; LIMITING VALUES; MATHEMATICAL EVOLUTION; OSCILLATIONS; PERTURBATION THEORY; SCALARS; SPACE; UNIVERSE