Dynamics of warm power-law plateau inflation with a generalized inflaton decay rate: predictions and constraints after Planck 2015

Abdul Jawad,Faiza Gulshan,Nelson Videla

doi:10.1140/epjc/s10052-017-4846-1

Abdul Jawad, Faiza Gulshan + Show 1 more

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https://doi.org/10.1140/epjc/s10052-017-4846-1

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Abstract

In the present work, we study the consequences of considering a new family of single-field inflation models, called power-law plateau inflation, in the warm inflation framework. We consider the inflationary expansion is driven by a standard scalar field with a decay ratio Gamma having a generic power-law dependence with the scalar field phi and the temperature of the thermal bath T given by Gamma (phi ,T)=C_{phi }frac{T^a}{phi ^{a-1}}. Assuming that our model evolves according to the strong dissipative regime, we study the background and perturbative dynamics, obtaining the most relevant inflationary observable as the scalar power spectrum, the scalar spectral index and its running and the tensor-to-scalar ratio. The free parameters characterizing our model are constrained by considering the essential condition for warm inflation, the conditions for the model evolves according to the strong dissipative regime and the 2015 Planck results through the n_mathrm{s}–r plane. For completeness, we study the predictions in the n_mathrm{s}–mathrm{d}n_mathrm{s}/mathrm{d}ln k plane. The model is consistent with a strong dissipative dynamics and predicts values for the tensor-to-scalar ratio and for the running of the scalar spectral index consistent with current bounds imposed by Planck and we conclude that the model is viable.

Highlights

Upon comparison to the current cosmological and astronomical observations, specially those related with the cosmic microwave background (CMB) temperature anisotropies, it is possible to constrain the inflationary models
In the present work, we study the consequences of considering a new family of single-field inflation models, called power-law plateau inflation, in the warm inflation framework
Assuming that our model evolves according to the strong dissipative regime, we study the background and perturbative dynamics, obtaining the most relevant inflationary observable as the scalar power spectrum, the scalar spectral index and its running and the tensor-toscalar ratio

Summary

Introduction

Upon comparison to the current cosmological and astronomical observations, specially those related with the CMB temperature anisotropies, it is possible to constrain the inflationary models. [32], the authors presented a toy-model in supergravity (SUGRA) which can produce the scalar potential of Plateau inflation (1) for n = 2 and q = 1 They considered only global supersymmetry (SUSY) and sub-Planckian fields with the superpotential. An interesting approach could be specify a decaying mechanism for the scalar components of the superfields 1 and 2 in light fields which form the thermal bath and compute the corresponding dissipative coefficient starting form first principles. This further considerations go beyond the scope of our present work, but these may be regarded as basis of a future work.

Background evolution

Cosmological perturbations

Discussion