Tachyon-Brane inflationary universe model in the context of a Chaplygin gas equation of state is studied. General conditions for this model to be realizable are discussed. In the high-energy limit and by using an exponential potential we describe in great details the characteristic of this model. Recent observational data from the Wilkinson Microwave Anisotropy Probe experiment are employed to restrict the parameters of the model.
Can an interacting varying Chaplygin gas and tachyonic matter accelerate Universe?
本文考虑了一种由于特定形式的变化的Chaubergin气体与快子物质相互作用而加速大尺度宇宙膨胀的可能性。一种特定形式的势和适当的参数值允许在近代宇宙中用$ω_{T} \approx 0$获得早期快子暗物质。另一方面，与描述背景动力学的场方程的结构有关，我们假定预先给出非引力相互作用的形式。暗能量与暗物质之间的相互作用是一个非常重要的研究领域。已确定casidered模型未来可能的有限时间奇点，以完成论文。研究表明，在非相互作用模型下，宇宙的命运要么是II型突然奇点，要么是IV型广义突然奇点。另一方面，除了考虑Ⅱ型和Ⅳ型奇点外，还考虑了$Q=3 b H ρ_{de}$非引力相互作用，将导致V型~（$ω$ -奇点）奇点。而在具有$Q=3 b q H ρ_{de}$非引力相互作用的模型中，只会观察到IV型奇点。此外，$2$形式的标度因子已被单独考虑，允许解析获得的宇宙学参数的行为，而不指定一个明确的形式的潜在的快子物质。
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 valu…
After a brief introduction to the AdS/CFT holography a tachyon inflation will be discussed in the framework of holographic cosmology. The model is based on a holographic braneworld scenario with an effective tachyon field on a D3-brane located at the holographic bound of an asymptotic ADS$_5$ bulk.
We present a tachyonic field inflationary model in a teleparallel framework. We show that tachyonic coupled with the f(T) gravity model can describe the inflation era in which f(T) is an arbitrary function of torsion scalar T. For this purpose, dynamical behavior of the tachyonic field in different potentials is studied, it is shown that the tachyonic field with these potentials can be an effective candidate for inflation. Then, we discuss slow-roll conditions and show that by the appropriate choice of the parameters, the inflation era can be explained via this model. Finally, we argue that ou…
For the constant-roll tachyon inflation, we derive the analytical expressions for the scalar and tensor power spectra, the scalar and tensor spectral tilts and the tensor to scalar ratio up to the first order by using the method of Bessel function approximation. The derived $n_s-r$ results for the constant-roll inflation are also compared with the observations, we find that only one constant-roll inflation is consistent with the observations and observations constrain the constant-roll inflation to be slow-roll inflation. The tachyon potential is also reconstructed for the constant-roll inflat…
In this work we study one of the most appealing string theory-motivated models, we present a tachyonic inflationary model in the recently proposed symmetric teleparallel framework, and examine constraints on tachyon inflation with the exponential potential along with the reheating for a chosen $f(Q)$ gravity model. Considering a reheating phase parametrized by a number of e-folds $N_{re},$ a temperature $T_{re}$, and an equation of state $ω_{re}$, we relate the reheating parameters as functions of the exponential tachyon potential, $f(Q)$ model, and\ the spectral index $n_{s}$ parameters. We a…
The Generalized Chaplygin Gas (GCG) model is characterized by the equation of state $P = -A ρ^{-α}$, where $A>0$ and $α< 1$. The model has been extensively studied due to its interesting properties and applicability in several contexts, from late-time acceleration to primordial inflation. Nonetheless we show that the inflationary slow-roll regime cannot be satisfied by most of the parameter space of the GCG model when General Relativity (GR) is considered. In particular, although the model has been applied to inflation with $0 < α< 1$, we show that for $-1 < α\le 1$ there is no expansion of th…
