Revisiting a pre-inflationary 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 pre-inflationary 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 pre-inflationary 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 e-folding more than what is required to solve cosmological problems, while only an upper bound on the inflaton temperature can be obtained.

29 pages, 3 figures, 2 tables, Matches with the published version

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Cited by in corpus (7)

• Warm bounce in loop quantum cosmology and the prediction for the duration of inflation
• Bonus Properties of States of Low Energy
• Semiclassical predictions regarding a pre-inflationary era and its effects on the power spectrum
• Thermal gravitational-wave background in the general pre-inflationary scenario
• Low Energy States and CPT invariance at the Big Bang
• Argument for the radiation-dominated behavior of matter fields in the preinflationary era
• Lowering tensor-to-scalar ratio by pre-inflationary dynamics