Tachyon warm-intermediate inflation in the light of Planck data

Vahid Kamali,Ahmad Mehrabi,Spyros Basilakos

doi:10.1140/epjc/s10052-016-4380-6

Vahid Kamali, Ahmad Mehrabi + Show 1 more

Open Access

https://doi.org/10.1140/epjc/s10052-016-4380-6

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Abstract

We study the main properties of the warm inflationary model based on Barrow's solution for the scale factor of the universe. Within this framework we calculate analytically the basic slow roll parameters for different versions of warm inflation. We test the performance of this inflationary scenario against the latest observational data and we verify that the predicted spectral index and the tensor-to-scalar fluctuation ratio are in excellent agreement with those of {\it Planck 2015}. Finally, we find that the current predictions are consistent with those of viable inflationary models.

Highlights

Standard inflation driven by an inflaton field traces back to early efforts to alleviate the basic problems of the Big-Bang cosmology, namely horizon, flatness, and monopoles [1,2]
In the slow-roll phase the kinetic energy of the scalar field is negligible with respect to the potential energy V (φ), which implies a de Sitter expansion of the universe
After the slow-roll epoch the kinetic energy becomes comparable to the potential energy and the inflaton field oscillates around the minimum and progressively the universe is filled by radiation [3,4]

Summary

Introduction

Standard inflation driven by an inflaton field traces back to early efforts to alleviate the basic problems of the Big-Bang cosmology, namely horizon, flatness, and monopoles [1,2]. Thermal fluctuations are produced during the warm-inflationary epoch and they play a central role toward describing the CMB anisotropies and providing the initial seeds for the formation of large scale structures After this epoch the universe enters in the radiation dominated phase as it should [5,6]. The reduction of higherdimensional gravitational scale, down to TeV-scale, could be presented by an extra dimensional scenario [15,16,17] In these scenarios, the gravity field propagates in the bulk, while standard models of particles are confined to the lowerdimensional brane. The gravity field propagates in the bulk, while standard models of particles are confined to the lowerdimensional brane In this framework, the extra dimension induces additional terms in the first Friedmann equation [18,19,20].

Tachyon warm inflation

Slow-roll parameters

Γ0-parametrization

Γ1-parametrization

Comparison with observation

Conclusions