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Register a new userOn Chaplygin Gas Braneworld Inflation with Monomial Potential
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In this paper we study the Chaplygin gas model as a candidate for inflation in the framework of the Randall Sundrum type-II braneworld model. We consider the original and generalized Chaplygin gas model in the presence of monomial potential. The inflationary spectrum perturbation parameters are reformulated and evaluated in the high-energy limit and we found that they depend on several parameters. We also showed that these perturbation parameters are widely compatible with the recent Planck data for a particular choice of the parameters space of the model. A suitable observational central value of $n_{s}simeq $ $0.965$ is also obtained in the case of original and generalized Chaplygin gas.
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In this paper, we examine the possible realization of a new family of inflation called shaft inflation by assuming the modified Chaplygin gas model and tachyon scalar field. We also consider the special form of dissipative coefficient as $Gamma={a_0}frac{T^{3}}{phi^{2 }}$ and calculate the various inflationary parameters in the scenario of strong and weak dissipative regimes. In order to examine the behavior of inflationary parameters, the planes of $n_s - phi,~n_s - r$ and $n_s - alpha_s$ (where $n_s,~alpha_s,~r$ and $phi$ represent spectral index, its running, tensor to scalar ratio and scalar field respectively) are being developed which lead to the constraints: $r< 0.11$, $n_s=0.96pm0.025$ and $alpha_s =-0.019pm0.025$. It is quite interesting that these results of inflationary parameters are compatible with BICEP$2$, WMAP $(7+9)$ and recent Planck data.
We consider a Chaplygin gas model with an exponential potential in framework of braneworld inflation. We apply the slow-roll approximation in the high-energy limit to derive various inflationary spectrum perturbation parameters. We show that the inflation observables depend only on the e-folding number N and the final value of the slow-roll parameter e(end). Whereas for small running of the scalar spectral index dns/dlnk, the inflation observables are in good agreement with recent WMAP7 data.
We investigate the role of bulk viscous pressure on the warm inflationary modified Chaplygin gas in brane-world framework in the presence of standard scalar field. We assume the intermediate inflationary scenario in strong dissipative regime and constructed the inflaton, potential, entropy density, slow-roll parameters, scalar and tensor power spectra, scalar spectral index and tensor-to-scalar ratio. We develop various trajectories such as $n_s - N$, $n_s - r$ and $n_s - alpha_s$ (where $n_s$ is the spectral index, $alpha_s$ is the running of spectral index, $N$ is the number of e-folds and $r$ is tensor-to-scalar ratio) for variable as well as constant dissipation and bulk viscous coefficients at high dissipative regime. It is interesting to remark here that our results of these parameters are compatible with recent observational data such as WMAP $7+9$, BICEP$2$ and Planck data.
Unification of dark matter and dark energy as short- and long-range manifestations of a single cosmological substance is possible in models described by the generalized Chaplygin gas equation of state. We show it admits halo-like structures and discuss their density profiles, the resulting space-time geometry and the rotational velocity profiles expected in these models.
We present a simple generalisation of the $Lambda$CDM model which on the one hand reaches very good agreement with the present day experimental data and provides an internal inflationary mechanism on the other hand. It is based on Palatini modified gravity with quadratic Starobinsky term and generalized Chaplygin gas as a matter source providing, besides a current accelerated expansion, the epoch of endogenous inflation driven by type III freeze singularity. It follows from our statistical analysis that astronomical data favors negative value of the parameter coupling quadratic term into Einstein-Hilbert Lagrangian and as a consequence the bounce instead of initial Big-Bang singularity is preferred.
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