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Title: The δN formula is the dynamical renormalization group

We derive the 'separate universe' method for the inflationary bispectrum, beginning directly from a field-theory calculation. We work to tree-level in quantum effects but to all orders in the slow-roll expansion, with masses accommodated perturbatively. Our method provides a systematic basis to account for novel sources of time-dependence in inflationary correlation functions, and has immediate applications. First, we use our result to obtain the correct matching prescription between the 'quantum' and 'classical' parts of the separate universe computation. Second, we elaborate on the application of this method in situations where its validity is not clear. As a by-product of our calculation we give the leading slow-roll corrections to the three-point function of field fluctuations on spatially flat hypersurfaces in a canonical, multiple-field model.
Authors:
;  [1] ;  [2]
  1. Astronomy Centre, University of Sussex, Falmer, Brighton, BN1 9QH (United Kingdom)
  2. Department of Physics, Case Western Reserve University, 10900 Euclid Ave, Cleveland, OH, 44106 (United States)
Publication Date:
OSTI Identifier:
22369958
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Cosmology and Astroparticle Physics; Journal Volume: 2013; Journal Issue: 10; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BY-PRODUCTS; CALCULATION METHODS; CORRECTIONS; CORRELATION FUNCTIONS; EXPANSION; FIELD THEORIES; FLUCTUATIONS; MASS; RENORMALIZATION; TIME DEPENDENCE; TREES