Powercounting during singlefield slowroll inflation
Abstract
We elucidate the counting of the relevant small parameters in inflationary perturbation theory. Doing this allows for an explicit delineation of the domain of validity of the semiclassical approximation to gravity used in the calculation of inflationary correlation functions. We derive an expression for the dependence of correlation functions of inflationary perturbations on the slowroll parameter epsilon = dot H/H^{2}, as well as on H M_{p}, where H is the Hubble parameter during inflation. Our analysis is valid for singlefield models in which the inflaton can traverse a Plancksized range in field values and where all slowroll parameters have approximately the same magnitude. As an application, we use our expression to seek the boundaries of the domain of validity of inflationary perturbation theory for regimes where this is potentially problematic: models with small speed of sound and models allowing eternal inflation.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 February 2018
 DOI:
 10.1088/14757516/2018/02/016
 arXiv:
 arXiv:1708.07443
 Bibcode:
 2018JCAP...02..016A
 Keywords:

 High Energy Physics  Theory;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology
 EPrint:
 20 pages, 1 figure