Revisiting a preinflationary radiation era and its effect on the CMB power spectrum
Abstract
We revisit the scenario where inflation is preceded by a radiation era by considering that the inflaton too could have been in thermal equilibrium early in the radiation era. Hence we take into account not only the effect of a preinflationary era on the inflaton mode functions but also that of a frozen thermal distribution of inflaton quanta. We initially discuss in detail the issues relevant to our scenario of a preinflationary radiation dominated era and then obtain the scalar power spectrum for this scenario. We find that the power spectrum is free from infrared divergences. We then use the WMAP and Planck data to determine the constraints on the inflaton comoving 'temperature' and on the duration of inflation. We find that the best fit value of the duration of inflation is less than 1 efolding more than what is required to solve cosmological problems, while only an upper bound on the inflaton temperature can be obtained.
 Publication:

Journal of Cosmology and Astroparticle Physics
 Pub Date:
 June 2015
 DOI:
 10.1088/14757516/2015/06/001
 arXiv:
 arXiv:1412.7093
 Bibcode:
 2015JCAP...06..001D
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 29 pages, 3 figures, 2 tables, Matches with the published version