We study the interacting agegraphic dark energy (ADE) model in non-flat universe by means of statefinder diagnostic and $w-w^{\prime}$ analysis. First, the evolution of EoS parameter ($w_d$) and deceleration parameter ($q$) in terms of scale factor for interacting ADE model in non-flat universe are calculated. Dependence of $w_d$ on the ADE model parameters $n$ and $α$ in different spatial curvatures is investigated. We show that the evolution of $q$ is dependent on the type of spatial curvature, beside of dependence on parameters $n$ and $α$. The accelerated expansion takes place sooner in open universe and later in closed universe compare with flat universe. Then, we plot the evolutionary trajectories of the interacting ADE model for different values of the parameters $n$ and $α$ as well as for different contributions of spatial curvature, in the statefinder parameters plane. In addition to statefinder, we also investigate the ADE model in non-flat universe with $w-w^{\prime}$ analysis.
Statefinder diagnostic and stability of modified gravity consistent with holographic and new agegraphic dark energy
最近，我们中的一个人推导出了与全息和新时代暗能量相一致的修正引力的作用。本文研究了[M. R. Setare，Int.J.Mod.Phys.D17（2008）2219; M. R. Setare，Astrophys.空间科学326（2010）27]。我们还计算了分类我们的暗能量模型的statefinder参数。
We present an autonomous phase-plane describing the evolution of field equations containing an agegraphic dark energy in 5D Brans- Dicke cosmology. To observationally verify the numerical results, we simultaneously solve the equations by constraining the model parameters with SNe Ia data. We find conditions for the existence and stability of the critical points (states of the universe) and numerically examine the cosmological parameters. We also investigate the model by means of statefinder diagnostic.
In this work, we explore the recently proposed new Tsallis agegraphic dark energy model in a flat FLRW Universe by taking the conformal time as IR cutoff with interaction. The deceleration parameter of the interacting new Tsallis agegraphic dark energy model provides the phase transition of the Universe from decelerated to accelerated phase. The EoS parameter of the model shows a rich behaviour as it can be quintessence-like or phantom-like depending on the interaction ($b^2$) and parameter $B$. The evolutionary trajectories of the statefinder parameters and $(ω_D, ω_D^{'})$ planes are plotted…
In this work, we have considered the recently proposed new Tsallis Agegraphic Dark Energy model (NTADE) (Mod. Phys. Lett. A 34, 1950086, 2019) within the framework of a flat Friedmann-Robertson-Walker(FRW) Universe by taking various values of the parameter $δ$. The NTADE model shows the current phase transition of the Universe from decelerated to accelerated phase. The NTADE EoS parameter shows a rich behaviour as it can be quintessence-like or phantom-like depending on the value of $δ$. For discriminating the NTADE model from $Λ$CDM, we have plotted the statefinder parameters $r(z)$, $s(z)$ a…
The aim of this work is to apply the dynamical system approach to study the linear dynamics of the normal DGP brane-world model with agegraphic dark energy. The stability analysis of the model will be investigated and the phase plane portrait will be illustrated. The nature of critical points will be analyzed by evaluating the eigenvalues of a linearized Jacobi matrix. Also, the statefinder diagnostic procedure will be applied to show the slight deviation from the ΛCDM model. One of the most interesting results of this work is the great alleviation of the coincidence problem.
We investigate the new Tsallis agegraphic dark energy (NTADE) scenario in the framework of Horava-Lifshitz cosmology. Considering interacting and non-interacting scenarios of NTADE with dark matter in a spatially non-flat universe, we investigate the cosmological implications of this model in detail. We obtain the differential equation of the evolution of the density parameter, the equation of state parameter and the classical stability of model. Also, we study the behavior of the deceleration parameter and investigate the nature of the statefinder diagnostics and $ω_D-{ω_D}^{\prime}$ plane. W…
We apply a series of null diagnostics based on the statefinder hierarchy to diagnose different holographic dark energy models including the original holographic dark energy, the new holographic dark energy, the new agegraphic dark energy, and the Ricci dark energy models. We plot the curves of statefinders $S^{(1)}_3$ and $S^{(1)}_4$ versus redshift $z$ and the evolutionary trajectories of $\{S^{(1)}_3, ε\}$ and $\{S^{(1)}_4, ε\}$ for these models, where $ε$ is the fractional growth parameter. Combining the evolution curves with the current values of $S^{(1)}_3$, $S^{(1)}_4$, and $ε$, we find …
A spatially homogeneous and anisotropic Bianchi type I universe is studied with the interacting holographic and new agegraphic scalar fields models of dark energy. Given, the framework of the anisotropic model, both the dynamics and potential of these scalar field models according to the evolutionary behavior of both dark energy models are reconstructed. We also investigate the cosmological evolution of interacting dark energy models, and compare it with observational data and schematic diagram. In order to do so, we focus on observational determinations of the expansion history $H(z)$. Next, …
In this work we study a non-flat Friedmann-Robertson-Walker universe filled with a pressure-less dark matter (DM) and Barrow holographic dark energy (BHDE) whose IR cutoff is the apparent horizon. Among various DE models, (BHDE) model shows the dynamical enthusiasm to discuss the universe's transition phase. According to the new research, the universe transitioned smoothly from a decelerated to an accelerated period of expansion in the recent past. We exhibit that the development of $q$ relies upon the type of spatial curvature. Here we study the equation of state (EoS) parameter for the BHDE …
In this paper, we have studied flat Friedmann--Lema\^ıtre--Robertson--Walker (FLRW) model with modified Chaplygin gas (MCG) having equation of state $p_{m}=Aρ-% \frac{B}{ρ^{γ}}$, where $0\leq A\leq 1$, $0\leq γ\leq 1$ and $B$ is any positive constant in }${\footnotesize f(R,T)}${\footnotesize \ gravity with particle creation. We have considered a simple parametrization of the Hubble parameter $H$ in order to solve the field equations and discussed the time evolution of different cosmological parameters for some obtained models showing unique behavior of scale factor. We have also discussed the…
We have analyzed the Barrow holographic dark energy (BHDE) in the framework of the flat FLRW Universe by considering the various estimations of Barrow exponent $\triangle$. Here we define BHDE, by applying the usual holographic principle at a cosmological system, for utilizing the Barrow entropy rather than the standard Bekenstein-Hawking. To understand the recent accelerated expansion of the universe, considering the Hubble horizon as the IR cut-off. The cosmological parameters, especially the density parameter ($Ω_{_D}$), the equation of the state parameter ($ω_{_D}$), energy density ($ρ_{_{…
We study non-viscous and viscous holographic dark energy models for a homogeneous and isotropic flat Friedmann-Robertson-Walker Universe in $f(R,T)$ gravity. We find that the Hubble horizon as an IR cut-off is suitable for both the models to explain the recent accelerated expansion of the Universe. The cosmological parameters like deceleration parameter and statefinder parameters are discussed in each model. In non-viscous model a constant deceleration parameter is found which shows that there is no phase transition. The constraints on the parameters are obtained to analyse the fixed point val…
The purpose of this paper is to study the Tsallis agegraphic dark energy with an interaction term between dark energy and dark matter in the DGP brane-world scenario. For this, we assume some initial conditions to obtain the dark energy density, deceleration, dark energy EoS, and total EoS parameters. Then, we analyze the statefinder parameters, $ω'{}_{DE}-ω_{DE}$ plots, and classical stability features of the model. The results state that the deceleration parameter provides the phase transition from decelerated to accelerated phase. The $ω_{DE}$ graphs show the phantom behavior, while the $ω_…
We study three interacting dark energy models within the framework of four-dimensional General Relativity and a spatially flat Universe. In particular, we first consider two vacuum models where dark energy interacts with dark matter, while relativistic matter as well as baryons are treated as non-interacting fluid components. Secondly, we investigate a third model where the gravitational coupling is assumed to be a slowly-varying function of the Hubble rate and dark energy and dark matter interact as well. We compute the statefinders parameters versus red-shift as well as the critical points a…
Statefinder diagnostic is a convenient method that can differentiate between the various dark energy models. In this article, we analyze the statefinder parameters in symmetric teleparallel cosmology. The $f(Q)$ gravity theory is an alternative theory to GR, where gravitational interactions attribute to the non-metricity scalar $Q$. In the present work, we consider two $f(Q)$ models which contains a linear and a non-linear form of non-metricity scalar, specifically, $f(Q)=αQ + \fracβ{Q}$ and $f(Q)=αQ + βQ^2$, where $α$ and $β$ are free parameters and then statefinder parameters $(r,s)$ are eva…
In this paper, we have used the state finder hierarchy for Barrow holographic dark energy (BHDE) model in the system of the FLRW Universe. We apply two DE diagnostic tools to determine $ΛBHDE$ model to have various estimations of $\triangle$. The first diagnostic tool is the state finder hierarchy in which we have studied $S^{(1)}_{3}$ $S^{(1)}_{4}$, $S^{(2)}_{3}$ $S^{(2)}_{4}$ and second is the composite null diagnostic (CND) in which the trajectories ( $S^{(1)}_{3} - ε$), ($S^{(1)}_{4}-ε$), ($S^{(2)}_{3}-ε$)($S^{(2)}_{4}-ε$) are discussed, where $ε$ is fractional growth parameter. The infrar…
It has been found that the geometrical diagnostic methods can break the degeneracy for dark energy models. In this paper, we investigate the $Om$ diagnostic, the statefinder hierarchy $S_{n}$ and the composite null diagnostic $\{S_{n},ε\}$ for the Tsallis holographic dark energy models with interactions. We find that model parameters and the forms of interaction will influence the values of diagnostic parameters or the trends of the evolutionary trajectories for each model. Moreover, the statefinder hierarchy $S_{3}^{(1)}$ together with $\{S_{3}^{(1)},ε\}$ could give good diagnostic results. F…
In this paper, we apply three diagnostics including $Om$, Statefinder hierarchy and the growth rate of perturbations into discriminating the two parametric models for the effective pressure with the $Λ$CDM model. By using the $Om$ diagnostic, we find that both the model 1 and the model 2 can be hardly distinguished from each other as well as the $Λ$CDM model in terms of 68\% confidence level. As a supplement, by using the Statefinder hierarchy diagnostics and the growth rate of perturbations, we discover that not only can our two parametric models be well distinguished from $Λ$CDM model, but a…
We focus on a series of $f(R)$ gravity theories in Palatini formalism to investigate the probabilities of producing the late-time acceleration for the flat Friedmann-Robertson-Walker (FRW) universe. We apply statefinder diagnostic to these cosmological models for chosen series of parameters to see if they distinguish from one another. The diagnostic involves the statefinder pair $\{r,s\}$, where $r$ is derived from the scale factor $a$ and its higher derivatives with respect to the cosmic time $t$, and $s$ is expressed by $r$ and the deceleration parameter $q$. In conclusion, we find that alth…
We apply the Statefinder hierarchy and the growth rate of matter perturbations to discriminate modified Chaplygin gas (MCG), generalized Chaplygin gas (GCG), superfluid Chaplygin gas (SCG), purely kinetic k-essence (PKK), and $Λ$CDM model. We plot the evolutional trajectories of these models in the statefinder plane and in the composite diagnostic plane. We find that GCG, MCG, SCG, PKK, and $Λ$CDM can be distinguished well from each other at the present epoch by using the composite diagnostic $\{ε(z), S^{(1)}_{5}\}$. Using other combinations, such as $\{S^{(1)}_{3}, S^{(1)}_4\}$, $\{S^{(1)}_{3…
In this paper, we constrain four time-dependent dark energy (TDDE) models by using the Type Ia supernovae (SNe Ia), baryonic acoustic oscillations (BAO), observational Hubble parameter (OHD) data-sets as well as the single data point from the newest event GW150914. Subsequently, adopting the best fitting values of the model parameters, we apply the original statefinder, statefinder hierarchy, the growth rate of matter perturbations and $Om(z)$ diagnostics to distinguish the TDDE scenarios and the $Λ$CDM scenario from each other. We discover that all the TDDE models and $Λ$CDM model can be dist…
Many dark energy (DE) models have been proposed, in recent years, to explain acceleration of the Universe expansion. It seems necessary to discriminate the various DE models in order to check the viability of each model. Statefinder diagnostic is a useful method which can differentiate various DE models. In this paper, we investigate the statefinder diagnosis parameters for the holographic dark energy (HDE) model in two cosmological setup. First, we study statefinder diagnosis for HDE in the context of flat Friedmann-Robertson-Walker (FRW) Universe in Einstein gravity. Then, we extend our stud…
In this work, we use the statefinder parameter diagnostic to the Holographic principal inspired dark energy models, taking into consideration, the Tsallis Holographic dark energy (THDE) model, the standard Holographic dark energy (HDE) model, and the R$\acute{e}$nyi holographic dark energy (RHDE) model. The evolutionary behaviour of first statefinder $r(z)$, second statefinder parameter $s(z)$, the statefinder parameter pairs $(r, s)$ and $(r, q)$ as well as the deceleration parameter $q(z)$ are plotted for comparison for the various parameter values of the respective dark energy models. In th…
With the use of simulated supernova catalogs, we show that the statefinder parameters turn out to be poorly and biased estimated by standard cosmography. To this end, we compute their standard deviations and several bias statistics on cosmologies near the concordance model, demonstrating that these are very large, making standard cosmography unsuitable for future and wider compilations of data. To overcome this issue, we propose a new method that consists in introducing the series of the Hubble function into the luminosity distance, instead of considering the usual direct Taylor expansions of …
In this paper, we examine a scenario in which late-time cosmic acceleration might arise due to the coupling between baryonic matter and dark matter without the presence of extra degrees of freedom. In this case, one can obtain late-time acceleration in Jordan frame and not in Einstein frame. We consider two different forms of parametrization of the coupling function, and put constraints on the model parameters by using an integrated datasets of Hubble parameter, Type Ia supernova and baryon acoustic oscillations. The models under consideration are consistent with the observations. In addition,…
One of the most favourable extensions of General Relativity is the $f(R)$ gravity. $f(R)$ gravity in Palatini formalism can be a realistic alternative to the dark energy problem. In this work we study a recently introduced dark energy $f(R)$ gravity model along with two other models in cosmological perspectives under the Palatini formalism. First, we study the cosmic expansion history of these models with the help of the important cosmographic parameters, such as the Hubble parameter, luminosity distance, effective equation of state etc. This study shows that the new model behaves similarly wi…
