Generalized interaction term inspired dark energy model in fractal universe

2020 ◽  
Vol 35 (15) ◽  
pp. 2050126
Author(s):  
Abdul Jawad ◽  
Saba Qummer ◽  
Shamaila Rani ◽  
M. Younas
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Energy Model ◽  
Linear Term ◽  
Accelerated Expansion ◽  
Linear Interaction ◽  
Interaction Term ◽  
The Universe

By assuming generalized nonlinear and linear interaction term between dark matter and dark energy, we investigate the cosmic accelerated expansion of the universe. For this reason, we suppose a flat fractal universe platform as well as Tsallis holographic dark energy model. The Hubble horizon is being adopted as an infrared cutoff and extracted different cosmological parameters as well as plane. It is observed that equation-of-state parameter exhibits the quintom-like nature while ([Formula: see text]–[Formula: see text]) lies in thawing and freezing regions for different parametric values for both the cases. Furthermore, the squared sound speed shows stable behavior for nonlinear interaction term but shows the partially stable behavior for linear term. For both cases, the deceleration parameter leads to the accelerated phase of the universe and the consequences are comparable with observational data. The results for [Formula: see text]–[Formula: see text] plane, leads to the quintessence and phantom region of the universe for nonlinear case while this plane represents the Chaplygin gas behavior for linear term. The [Formula: see text] diagnostic also shows the satisfying results.

scholarly journals Ghost Dark Energy Model with Non-linear Interaction

2018 ◽  
Vol 20 (1) ◽  
pp. 10
Author(s):  
SISTEMAS REVISTAS ◽  
Alexander Oliveros Garcia
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
State Parameter ◽  
Energy Model ◽  
Accelerated Expansion ◽  
Coupling Constant ◽  
Dark Energy Density ◽  
Small Perturbations ◽  
Linear Interaction ◽  
Non Linear

In this paper we study a dark energy model taking into account a non-linear interaction between the dark energy and dark matter components. The non-linear interaction term, used in this work, is proportional to the square of dark energy density. Considering a FRW type flat universe, we obtain an analytical expression for the Hubble parameter H and from this quantity, the deceleration parameter q and the equation of state parameter w Λ are analyzed. We found that, in this scenario, the accelerated expansion regime of the universe in late times is possible. However, using suitable values for the coupling constant, the square of the speed of sound remains negative, therefore, the model is unstable under small perturbations.

scholarly journals Thermodynamics of the viscous f(T,B) gravity in the new agegraphic dark energy model

2020 ◽  
Vol 35 (20) ◽  
pp. 2050166 ◽  
Author(s):  
A. Pourbagher ◽  
Alireza Amani
Keyword(s):  
Dark Energy ◽  
Hubble Parameter ◽  
Dark Energy Model ◽  
Apparent Horizon ◽  
Second Law Of Thermodynamics ◽  
Energy Model ◽  
Accelerated Expansion ◽  
Agegraphic Dark Energy ◽  
New Agegraphic Dark Energy ◽  
The Universe

In this paper, we first obtain the energy density by the approach of the new agegraphic dark energy model, and then the [Formula: see text] gravity model is studied as an alternative to the dark energy in a viscous fluid by flat-FRW background, in which [Formula: see text] and [Formula: see text] are torsion scalar and boundary term. The Friedmann equations will be obtained in the framework of modified teleparallel gravity by tetrad components. We consider that the universe dominates with components such as matter and dark energy by an interacting model. The Hubble parameter is parameterized by the power-law for the scale factor, and then we fit the corresponding Hubble parameter with observational data constraints. The variation of the equation of state (EoS) for dark energy is plotted as a function of the redshift parameter, and the accelerated expansion of the universe is explored. In what follows, the stability of the model is also studied on the base of the sound speed parameter. Finally, the generalized second law of thermodynamics is investigated by entropies of inside and on the boundary of the apparent horizon in thermodynamics equilibrium.

Ghost dark energy models in Bianchi I cosmologies with modified gravity

2014 ◽  
Vol 92 (2) ◽  
pp. 168-172 ◽  
Author(s):  
V. Fayaz ◽  
H. Hossienkhani ◽  
A. Aghamohammadi ◽  
M. Amirabadi
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
General Scheme ◽  
Energy Model ◽  
Accelerated Expansion ◽  
Type I ◽  
Field Equations ◽  
Ghost Dark Energy ◽  
Expansion Of The Universe ◽  
The Universe

A ghost dark energy model has been recently put forward to explain the current accelerated expansion of the universe. In this model, we develop the general scheme for modified f(R) gravity reconstruction from realistic anisotropic Bianchi type I cosmology. Power-law volumetric expansion is used to obtain exact solutions of the field equations. We discuss the physical behavior of the solutions and anisotropy behavior of the fluid, the expansion parameter, and the model in future evolution of the universe. We reconstruct corresponding f(R) gravities and obtain the equation of state parameter. We show that the corresponding f(R) gravity of the ghost dark energy model can behave like phantom or quintessence of the selected models that describe accelerated expansion of the universe.

scholarly journals Barrow HDE model for statefinder diagnostic in FLRW universe

2021 ◽  
pp. 2150030
Author(s):  
Anirudh Pradhan ◽  
Archana Dixit ◽  
Vinod Kumar Bhardwaj
Keyword(s):  
Dark Energy ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Accelerated Expansion ◽  
Density Parameter ◽  
Phantom Divide ◽  
Phantom Divide Line ◽  
Expansion Of The Universe ◽  
Flrw Universe ◽  
The Universe

We have analyzed the Barrow holographic dark energy (BHDE) in the framework of flat FLRW universe by considering the various estimations of Barrow exponent △. 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, consider the Hubble horizon as the IR cutoff. The cosmological parameters, especially the density parameter [Formula: see text], the equation of the state parameter [Formula: see text], energy density [Formula: see text] and the deceleration parameter [Formula: see text] are studied in this paper and found the satisfactory behaviors. Moreover we additionally focus on the two geometric diagnostics, the statefinder [Formula: see text] and [Formula: see text] to discriminant BHDE model from the [Formula: see text]CDM model. Here we determined and plotted the trajectories of evolution for statefinder [Formula: see text], [Formula: see text] and [Formula: see text] diagnostic plane to understand the geometrical behavior of the BHDE model by utilizing Planck 2018 observational information. Finally, we have explored the new Barrow exponent △, which strongly affects the dark energy equation of state that can lead it to lie in the quintessence regime, phantom regime and exhibits the phantom-divide line during the cosmological evolution.

scholarly journals Evolution of non-flat cosmos via GGPDE f(R) model

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Wajiha Javed ◽  
Iqra Nawazish ◽  
Fatima Shahid ◽  
Nimra Irshad
Keyword(s):  
Dark Energy ◽  
Power Law ◽  
Dark Energy Model ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Scale Factor ◽  
Energy Model ◽  
Density Parameter ◽  
Shift Parameter ◽  
Scale Factors

Abstract This paper is devoted to explore the cosmic evolution of non-flat Friedmann Robertson Walker universe through generalized ghost pilgrim dark energy model in the background of f(R) gravity. For this purpose, we consider two well known scale factors, i.e., power-law and unified scale factors in terms of red shift parameter. For these scale factors, we reconstruct the given dark energy model in f(R) gravity and determine its stability/instability through squared speed of sound parameter. In order to discuss the behavior of reconstructed and dark energy models, we evaluate well known cosmological parameter such as equation of state parameter along with $$\omega $$ω–$$\omega '$$ω′ plane. In addition to this, we also investigate compatibility of new models with standard cosmological models through state-finder parameters. The density parameter is formulated for both ordinary matter as well as dark energy components and results are compared with Planck 2018 constraints. It is concluded that cosmological parameters reveal consistency with recent observations while the value of density parameter suggested by Planck 2018 is achieved by power-law scale factor in most of the cases as compared to unified scale factor.

Dynamics of a quintom dark energy model non-minimally coupled with a mixed kinetic geometric term

2020 ◽  
Author(s):  
Mihai Marciu
Keyword(s):  
Dark Energy ◽  
Dark Energy Model ◽  
Energy Model ◽  
Accelerated Expansion ◽  
Field Equations ◽  
Distant Future ◽  
Phantom Divide ◽  
Phantom Divide Line ◽  
Big Crunch ◽  
The Universe

Within this work, a new dark energy model it is proposed, by taking into account a non-minimally mixed kinetic geometric coupling between the two fields which construct a quintom model. By considering numerical analysis of the corresponding field equations, the evolution of the Universe in the present model has been analyzed, taking into account different viable potentials. For exponential potentials, the model presents an accelerated expansion, and the dark energy equation of state exhibit the phantom divide line crossing. However, for a steeper potential, in the case of a mixed potential, it is observed that the Universe can manifest Big Crunch singularities in the distant future, and the moment for which the singularity occur is sensitive to the value of the mixed coupling strength embedded into the η coeffcient. The results show that an increase of the $\eta$ parameter determine a delay in the the Big Crunch time in the distant future. In the present context, the choice of the potential function play a fundamental role in the evolution of the dynamical system, leading to very distinct cosmological scenarios.

scholarly journals Cosmological Analysis of Modified Holographic Ricci Dark Energy in Chern-Simons Modified Gravity

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Sarfraz Ali ◽  
M. Jamil Amir
Keyword(s):  
Dark Energy ◽  
Modified Gravity ◽  
Dark Energy Model ◽  
State Parameter ◽  
Scalar Fields ◽  
Energy Model ◽  
Accelerated Expansion ◽  
Ricci Dark Energy ◽  
Dominant Component ◽  
Chern Simons

In this paper, we study the cosmological analysis of the modified holographic Ricci dark energy model and reconstruct different scalar field models in the context of Chern-Simons modified gravity. We investigate the deceleration parameter, which shows that the universe is in the accelerating expansion phase. The equation of state parameter in this case also favors the fact that dark energy is the dominant component of universe, which is responsible for the accelerated expansion. A number of scalar fields, such as quintessence, tachyon, K-essence, and dilaton models, are reconstructed using modified holographic Ricci dark energy model in the context of dynamical CS modified gravity. The quintessence and K-essence models represent exponentially increasing behaviors, while tachyon model shows decreasing behavior. Unfortunately, the dilaton model has no numerical solution for modified holographic Ricci dark energy model in the framework of dynamical Chern-Simons modified gravity.

scholarly journals The influence of the dark energy model in the Roche potential for interacting galaxies

2020 ◽  
pp. 127-130
Author(s):  
U.N. Zakirov ◽  
Keyword(s):  
Dark Energy ◽  
Equivalence Principle ◽  
Dark Energy Model ◽  
Energy Model ◽  
Interacting Galaxies ◽  
Vacuum Field ◽  
Accelerated Expansion ◽  
Expansion Of The Universe ◽  
First Time ◽  
The Universe

For the first time, the influence of the dark energy model - a new non-vacuum field - in the generalized (with allowance for the equivalence principle) Roche potential for interacting galaxies was considered. The equation of thermodynamics of the mentioned field and its possible evolutions affecting on the accelerated expansion of the Universe is given.

Interacting new holographic dark energy model with varying G in nonflat universe

2013 ◽  
Vol 91 (12) ◽  
pp. 1090-1092
Author(s):  
V. Fayaz ◽  
F. Felegary ◽  
H. Hossienkhani
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Dark Energy Model ◽  
Holographic Dark Energy ◽  
Energy Model ◽  
Accelerated Expansion ◽  
Late Time ◽  
Holographic Dark Energy Model ◽  
Expansion Of The Universe ◽  
The Universe

Motivated by the work of Karami and Fehri (Phys. Lett. B, 684, 61 (2010)). We generalize their work with varying G. We investigate the new holographic dark energy model with varying G. We consider a spatially nonflat universe containing interacting new holographic dark energy with pressureless dark matter. We obtain the equation of state and the deceleration parameters. Also we reconstruct ωA for a = a0tn and H = [β/(α − 1)](1/t) in the late time universe. We also obtain q for a = a0tn and H = [β/(α − 1)](1/t) in the present time universe, which describes accelerated expansion of the universe.

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