Please use this identifier to cite or link to this item: http://hdl.handle.net/2248/5590
Title: Reheating in tachyonic inflationary models: Effects on the large scale curvature perturbations
Authors: Jain, R. K
Pravabati, C
Sriramkumar, L
Keywords: Inflationary models;Cosmological perturbation theory;Reheating
Issue Date: Nov-2011
Publisher: Elsevier B.V.
Citation: Nuclear Physics B, Vol. 852, No. 2, pp. 366-389
Abstract: We investigate the problem of perturbative reheating and its effects on the evolution of the curvature perturbations in tachyonic inflationary models. We derive the equations governing the evolution of the scalar perturbations for a system consisting of a tachyon and a perfect fluid. Assuming the perfect fluid to be radiation, we solve the coupled equations for the system numerically and study the evolution of the perturbations from the sub-Hubble to the super-Hubble scales. In particular, we analyze the effects of the transition from tachyon driven inflation to the radiation dominated epoch on the evolution of the large scale curvature and non-adiabatic pressure perturbations. We consider two different potentials to describe the tachyon and study the effects of two possible types of decay of the tachyon into radiation. We plot the spectrum of curvature perturbations at the end of inflation as well as at the early stages of the radiation dominated epoch. We find that reheating does not affect the amplitude of the curvature perturbations in any of these cases. These results corroborate similar conclusions that have been arrived at earlier based on the study of the evolution of the perturbations in the super-Hubble limit. We illustrate that, before the transition to the radiation dominated epoch, the relative non-adiabatic pressure perturbation between the tachyon and radiation decays in a fashion very similar to that of the intrinsic entropy perturbation associated with the tachyon. Moreover, we show that, after the transition, the relative non-adiabatic pressure perturbation dies down extremely rapidly during the early stages of the radiation dominated epoch. It is these behavior which ensure that the amplitude of the curvature perturbations remain unaffected during reheating. We also discuss the corresponding results for the popular chaotic inflation model in the case of the canonical scalar field.
Description: Restricted Access
URI: http://hdl.handle.net/2248/5590
???metadata.dc.rights???: © Elsevier B.V.
???metadata.dc.relation.uri???: http://dx.doi.org/10.1016/j.nuclphysb.2011.07.003
http://arxiv.org/abs/0902.1067
Appears in Collections:IIAP Publications

Files in This Item:
File Description SizeFormat 
Reheating in tachyonic inflationary models.pdfRestricted Access409.78 kBAdobe PDFView/Open    Request a copy


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.