Tachyon warm-intermediate inflation in the light of Planck data

Kamali, Vahid; Basilakos, Spyros; Mehrabi, Ahmad

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

Cited by 21 publications

(15 citation statements)

References 75 publications

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“…The scalar tilt and the tensor-to-scalar ratio are Steer and Vernizzi [28] considered the special case with p = 4. Inserting Equation (6.33.128) into Equation (6.33.20), the horizon slow roll parameters are found to be [204] have investigated tachyon warm-intermediate inflation in light of the Planck data. They have noted that while in cold standard tachyon inflation reheating is problematic because the tachyon fields in such models do not oscillate around the minimum of the potential, this problem can be alleviated in the context of warm inflation, where production of radiation occurs during the slow-roll era, which implies that reheating is not necessary.…”

Section: General Tachyon Inflation Equationsmentioning

confidence: 99%

Predictions of Spectral Parameters by Several Inflationary Universe Models in Light of the Planck Results

Grøn

2018

Universe

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I give a review of predictions of values of spectral parameters for a large number of inflationary models. The present review includes detailed deductions and information about the approximations that have been made, written in a style that is suitable for text book authors. The Planck data have the power of falsifying several models of inflation as shown in the present paper. Furthermore, they fix the beginning of the inflationary era to a time about 10 −36 s, and the typical energy of a particle at this point of time to 10 16 GeV, only a few orders of magnitude less than the Planck energy, and at least 12 orders of magnitude larger than the most energetic particle produced by CERN's particle accelerator, LHC. This is a phenomenological review with contents as given in the list below. It includes systematic presentations of the different types of slow roll parameters that have been in use, and also of the N-formalism.

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Section: General Tachyon Inflation Equationsmentioning

confidence: 99%

Predictions of Spectral Parameters by Several Inflationary Universe Models in Light of the Planck Results

Grøn

2018

Universe

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“…The simplest form is a constant dissipative coefficient, although it may have a general functional form of temperature T and scalar field φ inspired from supersymmetry [99]. On the other hand, it can be proportional to a potential ( ∝ V ) which has also been considered [67][68][69][70][71][72][73][74][75][76] in numerous works. The interested reader can find a full set of derivation of such an assumption in Appendix B of [100] where the authors have invoked the method presented in [42] which is based on thermal effective field theory analyzing intermediate particle production to achieve their goal.…”

Section: Exponential Potentialmentioning

confidence: 99%

“…Using this value and Eqs. (69), (73), (75), and (76), we can find the value of the spectral index, its running and tensor-to-scalar ratio for different values of free parameters. We have also plotted tensor-to-scalar ratio, its running and the spectral index for gravitational waves versus scalar spectral index.…”

Section: Exponential Potential With Power-law Gauss-bonnet Couplingmentioning

confidence: 99%

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Warm-tachyon Gauss–Bonnet inflation in the light of Planck 2015 data

Motaharfar

Sepangi

2016

Eur. Phys. J. C

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We study a warm-tachyon inflationary model non-minimally coupled to a Gauss-Bonnet term. The general conditions required for reliability of the model are obtained by considerations of a combined hierarchy of Hubble and Gauss-Bonnet flow functions. The perturbed equations are comprehensively derived in the longitudinal gauge in the presence of slow-roll and quasi-stable conditions. General expressions for observable quantities of interest such as the tensor-to-scalar ratio, scalar spectral index and its running are found in the high dissipation regime. Finally, the model is solved using exponential and inverse power-law potentials, which satisfy the properties of a tachyon potential, with parameters of the model being constrained within the framework of the Planck 2015 data. We show that the GaussBonnet coupling constant controls termination of inflation in such a way as to be in good agreement with the Planck 2015 data.

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“…Therefore in the post-inflation era the tachyon density would always dominate radiation unless there is a mechanism by which tachyon decay into radiation. Our tachyon model in the present work is an unphysical toy model but there is a solution for reheating problem in the context of warm inflation [10][11][12][13][14][15][16][17], which however is beyond the scope of the present work. From the dynamical viewpoint one may present the equation of motion of tachyon field using a special Lagrangian [18] which is nonminimally coupled to gravity:Considering a spatially flat Friedmann−Lemaitre−Robertson− Walker (FLRW) (hereafter FLRW) universe the stress-energy tensor components are presented byequation where ρ φ and p φ are the energy density and pressure of the tachyon field.…”

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confidence: 99%

Tachyon logamediate inflation on the brane

Kamali

Nik

2017

Eur. Phys. J. C

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According to a Barrow solution for the scale factor of the universe, the main properties of the tachyon inflation model in the framework of the RSII braneworld are studied. Within this framework the basic slow-roll parameters are calculated analytically. We compare this inflationary scenario to the latest observational data. The predicted spectral index and the tensor-to-scalar fluctuation ratio are in excellent agreement with those of Planck 2015. The current predictions are consistent with those of viable inflationary models. The set up and motivationThe standard model of inflation is driven by a scalar inflaton (quanta of the inflationary field) field can be traced back to early efforts to solve the basic problems of the Big-Bang cosmology, namely horizon, flatness and monopole [1,2] problems. The nominal inflationary paradigm contains two mainly different segments: the slow-roll and the (p)reheating regimes. In the slow-roll phase the kinetic part of energy (which has the canonical form here) of the scalar field is negligible with respect to the potential part of energy V (φ), which implies a nearly de Sitter expansion of the universe. However, after the slow-roll epoch the kinetic energy becomes comparable to the potential energy and thus the inflaton field oscillates around the minimum at the (p)reheating phase and progressively the universe is filled by radiation [3,4]. In order to achieve inflation one can use tachyon scalar fields for which the kinetic term does not follow the canonical form (kinflation [5]). It has been found that tachyon fields which are associated with unstable D-branes [6] may be responsible for the cosmic acceleration phase in early times [5,7,8]. Notice that the tachyon potential has the following two properties: the maximum of the potential occurs when φ → 0, while a

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Tachyon warm-intermediate inflation in the light of Planck data

Cited by 21 publications

References 75 publications

Predictions of Spectral Parameters by Several Inflationary Universe Models in Light of the Planck Results

Predictions of Spectral Parameters by Several Inflationary Universe Models in Light of the Planck Results

Warm-tachyon Gauss–Bonnet inflation in the light of Planck 2015 data

Tachyon logamediate inflation on the brane

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