Study of inflationary generalized cosmic Chaplygin gas for standard and tachyon scalar fields

Sharif, M.; Saleem, Rabia

doi:10.1140/epjc/s10052-014-2943-y

Cited by 21 publications

(9 citation statements)

References 52 publications

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“…It is worth mentioning here that all the results for intermediate regime with standard scalar field without Π reduce to [38,39]. Our results for this model support the results of [61] that this model is less effective as compared to MCG and other DE models.…”

Section: Discussionsupporting

confidence: 84%

“…Herrera et al [38] studied intermediate GCG inflationary universe model with standard as well as tachyon scalar fields and checked its compatibility with WMAP7 data. We have also studied inflationary dynamics of GCCG with standard and tachyon scalar fields during intermediate and logamediate scenarios [39]. A detailed analysis on the dynamics of warm inflation with viscous pressure is presented in [40].…”

Section: Jcap12(2014)038mentioning

confidence: 99%

“…In this paper, we follow [41,42] to study the consequences of bulk viscous pressure on our previous paper [39] during intermediate era. The paper has the following format.…”

Section: Jcap12(2014)038mentioning

confidence: 99%

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Effects of viscous pressure on warm inflationary generalized cosmic Chaplygin gas model

Sharif

Saleem²

2014

J. Cosmol. Astropart. Phys.

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This paper is devoted to study the effects of bulk viscous pressure on an inflationary generalized cosmic Chaplygin gas model using FRW background. The matter contents of the universe are assumed to be inflaton and imperfect fluid. We evaluate inflaton fields, potentials and entropy density for variable as well as constant dissipation and bulk viscous coefficients in weak as well as high dissipative regimes during intermediate era. In order to discuss inflationary perturbations, we evaluate entropy density, scalar (tensor) power spectra, their corresponding spectral indices, tensor-scalar ratio and running of spectral index in terms of inflaton which are constrained using recent Planck, WMAP7 and Bicep2 probes.

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Section: Discussionsupporting

confidence: 84%

Section: Jcap12(2014)038mentioning

confidence: 99%

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Effects of viscous pressure on warm inflationary generalized cosmic Chaplygin gas model

Sharif

Saleem²

2014

J. Cosmol. Astropart. Phys.

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“…Sharif and Saleem [33] discussed inflationary dynamics inspired by GCCG ('generalized cosmic Chapygin gas') using standard and tachyonic fields in 'intermediate' and 'logamediate' scenarios. The same authors presented a detailed analysis on the dynamics of warm viscous inflation taking isotropic and an anisotropic universe describing by Bianchi I model [34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Inflationary solution of Hamilton Jacobi equations during weak dissipative regime

Saleem

Zubair

2020

Phys. Scr.

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In this paper, an elegant mathematical approach is introduced to solve the equations of warm inflationary model without using extra approximations other than slow-roll. This important inflationary method known as Hamilton-Jacobian formalism. Here tachyon field and the imperfect fluid are considered to be the cosmic ingredients to create inflation. A general formalism is developed for the considered inflationary model and further work is restricted to weak dissipative regime. A detailed analysis of the model is presented for three different choices of bulk and dissipative coefficients taking as constant as well as variable (function of Hubble parameter and inflaton). In each case, the involved model parameters are constrained to plot the physical acceptable range of scalar spectral index and tensor to scalar ratio. The parametric trajectories proved that the acquired results for all the three cases are compatible with Planck astrophysical data. Furthermore, the existence of warm inflation and slow-roll limit are also verified graphically.

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“…Models that extend beyond ΛCDM include scalar field inflationary models [4], and in recent years various models have been proposed with a modified equation of state [5,6]. Chaplygin gas [7][8][9][10][11][12][13][14][15][16][17][18][19] and Van der Waals quintessence [20][21][22][23][24][25][26] models, for example, provide accurate qualitative descriptions of the universal expansion in different epochs of the cosmic evolution. These models can be constrained not only from observations of the current epoch of a late-time accelerated expansion, but may also be cast in the form of a scalar field in the early universe.…”

Section: Introductionmentioning

confidence: 99%

Inflationary Constraints on the Van der Waals Equation of State

Vardiashvili¹,

Halstead²,

Morgan³

et al. 2017

Preprint

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In spite of the strong observational evidence suggesting a period of rapid expansion in the early universe, the identity of the inflaton field that drove this expansion remains elusive. Many inflaton candidate particles (both known and hypothesized) have been proposed to explain the early accelerated expansion of the universe. Other explanations for an era of rapid expansion in the early universe have been proposed via modifications of gravity in one form or another.In this paper, we consider the possibility of using a Van der Waals equation of state to describe the early-time accelerated expansion of the universe. We do not attempt to explain why the early universe may be filled with such a fluid, but rather investigate what constraints may be placed on the parameters which describe a Van der Waals fluid that sources an accelerated expansion in the early universe. We consider three different versions of the Van der Waals equation of state and constrain the parameters of each using CMB data. We find that two of the models do not fit constraints from observation. A third model may satisfy observational constraints, but only under very narrow circumstances.

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Study of inflationary generalized cosmic Chaplygin gas for standard and tachyon scalar fields

Cited by 21 publications

References 52 publications

Effects of viscous pressure on warm inflationary generalized cosmic Chaplygin gas model

Effects of viscous pressure on warm inflationary generalized cosmic Chaplygin gas model

Inflationary solution of Hamilton Jacobi equations during weak dissipative regime

Inflationary Constraints on the Van der Waals Equation of State

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