Scenario of two-fluid dark energy models in Bianchi type-III Universe

2018 ◽  
Vol 15 (11) ◽  
pp. 1850189 ◽  
Author(s):  
Rishi Kumar Tiwari ◽  
Aroonkumar Beesham ◽  
Bhupendra Kumar Shukla
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Bianchi Type ◽  
Cosmological Parameters ◽  
Cosmic Time ◽  
Physical Parameters ◽  
Field Equations ◽  
Barotropic Fluid ◽  
Type Iii ◽  
The Universe

In this paper, we have analyzed the equation of state parameter for dark energy in the spatially homogeneous and anisotropic Bianchi type-III spacetime filled with a barotropic fluid and dark energy by considering a variable deceleration parameter. To solve the Einstein field equations, we assume that the expansion scalar is proportional to the shear scalar. We find that during the evolution of the Universe, the equation of state and the cosmological parameters are positive decreasing functions of cosmic time [Formula: see text]. Also, we discuss the physical parameters, as well as the jerk and cosmic span parameters, which predict that the Universe in this model approaches the [Formula: see text]CDM model at late times.

Kaluza–Klein dark energy model in the form of wet dark fluid in f(R, T) gravity

2014 ◽  
Vol 92 (9) ◽  
Author(s):  
P.K. SAHOO ◽  
B. Mishra
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Accelerated Expansion ◽  
Physical Parameters ◽  
Late Time ◽  
Field Equations ◽  
Wet Dark Fluid ◽  
Dark Fluid ◽  
The Universe ◽  
Kaluza Klein

A five dimensional Kaluza-Klein space time is considered with wet dark fluid (WDF) source in the framework of f(R,T) gravity, where R is the Ricci scalar and T is the trace of the energy-momentum tensor proposed by Harko et al. (Phys. Rev. D \textbf{84}, 024020, (2011)). A new equation of state in the form of WDF has been used for dark energy (DE) component of the universe. It is modeled on the equation of state p=\omega(\rho-\rho^*) which can be describing a liquid, for example water. The exact solutions to the corresponding field equations are obtained for power law and exponential law of the volumetric expansion. The geometrical and physical parameters for both the models are studied. The model obtained here may represent the inflationary era in the early universe and the very late time of the universe. This model obtained here shows that even in the presence of wet dark fluid, the universe indicates accelerated expansion of the universe.

Kaluza–Klein dark energy model in the form of wet dark fluid in f(R, T) gravity

2014 ◽  
Vol 92 (9) ◽  
pp. 1062-1067 ◽  
Author(s):  
P. K. Sahoo ◽  
B. Mishra
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Accelerated Expansion ◽  
Physical Parameters ◽  
Late Time ◽  
Field Equations ◽  
Wet Dark Fluid ◽  
Dark Fluid ◽  
The Universe ◽  
Kaluza Klein

In this paper, we have investigated the five-dimensional Kaluza–Klein space time with wet dark fluid (WDF), which is a candidate for dark energy (DE), in the framework of f(R, T) gravity. R and T denote the Ricci scalar and the trace of the energy–momentum tensor, respectively (Harko et al. Phys. Rev. D, 84, 024020 (2011)). We have used equation of state in the form of WDF for the DE component of the universe. It is modeled on the equation of state p = ω(ρ – ρ*). With the help of the power law and exponential law of volumetric expansion, we have derived the exact solutions of the corresponding field equations. The geometrical and physical parameters for both the models are studied. The model obtained here may represent the inflationary era in the early universe and very late time of the universe. It is concluded that the model obtained here shows that even in the presence of WDF, the universe indicates accelerated expansion of the universe.

Probing kinematics and fate of Bianchi type V Universe

2020 ◽  
Vol 35 (27) ◽  
pp. 2050224
Author(s):  
G. K. Goswami ◽  
Anil Kumar Yadav ◽  
B. Mishra
Keyword(s):  
Dark Energy ◽  
Bianchi Type ◽  
Cosmological Parameters ◽  
Late Time ◽  
Barotropic Fluid ◽  
Dark Energy Component ◽  
Bianchi Type V Universe ◽  
Type V ◽  
The Universe ◽  
Bianchi Type V

In this paper, we have constrained the cosmological parameters of Bianchi type V universe by bounding the model under consideration with recent observational [Formula: see text] and Pantheon data. It is assumed that the energy conservation law holds separately for barotropic fluid and dark energy fluid i.e. dark energy component does not interact with barotropic matter. We obtain the present value of deceleration parameter and age of universe as [Formula: see text] and 13.329 Gyrs respectively. The analysis of [Formula: see text] and jerk parameters concur that the derived model approaches [Formula: see text]CDM universe at late time. We find that estimated values of Hubble’s constant and energy density parameters have pretty consistency with their corresponding values, obtained by recent observations of WMAP and PLANCK collaborations. It is also observed that the universe shows signature flipping from decelerating to accelerating phase for transitional red-shift value [Formula: see text] in past.

Interacting holographic dark energy in Bianchi type-V and IX universes with variable deceleration parameter

2020 ◽  
Vol 17 (10) ◽  
pp. 2050160
Author(s):  
H. Eser ◽  
C. B. Kilinc
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Deceleration Parameter ◽  
Bianchi Type ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
Field Equations ◽  
Variable Deceleration Parameter ◽  
Type V ◽  
Bianchi Type V

In this paper, we study spatially homogeneous and anisotropic Bianchi type-V and IX universes filled with interacting dark matter and holographic dark energy. We obtained the solution of the field equations by using the variable deceleration parameter in the form [Formula: see text]. The cosmological parameters of the models like deceleration and equation of state are obtained. We observe that the deceleration parameter tends to [Formula: see text] which shows an accelerated universe, and the equation of state tends to [Formula: see text] which belongs to [Formula: see text]CDM model. Moreover, we establish the correspondence between holographic dark energy model and quintessence scalar field.

scholarly journals Physical Acceptability of the Renyi, Tsallis and Sharma-Mittal Holographic Dark Energy Models in the f(T,B) Gravity under Hubble’s Cutoff

Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 67
Author(s):  
Salim Harun Shekh ◽  
Pedro H. R. S. Moraes ◽  
Pradyumn Kumar Sahoo
Keyword(s):  
Dark Energy ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
Field Equations ◽  
Eos Parameter ◽  
Two Fluids ◽  
Gravitational Field Equations ◽  
Energy Models ◽  
Different Types ◽  
The Universe

In the present article, we investigate the physical acceptability of the spatially homogeneous and isotropic Friedmann–Lemâitre–Robertson–Walker line element filled with two fluids, with the first being pressureless matter and the second being different types of holographic dark energy. This geometric and material content is considered within the gravitational field equations of the f(T,B) (where T is the torsion scalar and the B is the boundary term) gravity in Hubble’s cut-off. The cosmological parameters, such as the Equation of State (EoS) parameter, during the cosmic evolution, are calculated. The models are stable throughout the universe expansion. The region in which the model is presented is dependent on the real parameter δ of holographic dark energies. For all δ≥4.5, the models vary from ΛCDM era to the quintessence era.

scholarly journals Bianchi type-III Tsallis holographic dark energy model in Saez–Ballester theory of gravitation

2020 ◽  
Vol 80 (12) ◽  
Author(s):  
M. Vijaya Santhi ◽  
Y. Sobhanbabu
Keyword(s):  
Dark Energy ◽  
Bianchi Type ◽  
Graphical Representation ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
State Parameter ◽  
Field Equations ◽  
Om Diagnostic ◽  
Hubble Radius ◽  
Theory Of Gravitation

AbstractIn this paper, we have investigated Tsallis holographic dark energy (infrared cutoff is the Hubble radius) in homogeneous and anisotropic Bianchi type-III Universe within the framework of Saez–Ballester scalar–tensor theory of gravitation. We have constructed non-interaction and interaction dark energy models by solving the Saez–Ballester field equations. To solve the field equations, we assume a relationship between the metric potentials of the model. We developed the various cosmological parameters (namely deceleration parameter q, equation of state parameter $$\omega _t$$ ω t , squared sound speed $$v_s^2$$ v s 2 , om-diagnostic parameter Om(z) and scalar field $$\phi $$ ϕ ) and well-known cosmological planes (namely $$\omega _t-\omega _t^{'}$$ ω t - ω t ′ plane, where $$'$$ ′ denotes derivative with respect to ln(a) and statefinders ($$r-s$$ r - s ) plane) and analyzed their behavior through graphical representation for our both the models. It is also, quite interesting to mention here that the obtained results are coincide with the modern observational data.

scholarly journals An accelerating cosmological model from a parametrization of Hubble parameter

2019 ◽  
Vol 35 (05) ◽  
pp. 2050011 ◽  
Author(s):  
S. K. J. Pacif ◽  
Md Salahuddin Khan ◽  
L. K. Paikroy ◽  
Shalini Singh
Keyword(s):  
Dark Energy ◽  
Cosmological Model ◽  
Hubble Parameter ◽  
Cosmological Parameters ◽  
Cosmic Time ◽  
Solution Procedure ◽  
Cosmic Acceleration ◽  
Model Parameters ◽  
Late Time ◽  
Field Equations

In view of late-time cosmic acceleration, a dark energy cosmological model is revisited wherein Einstein’s cosmological constant is considered as a candidate of dark energy. Exact solution of Einstein field equations (EFEs) is derived in a homogeneous isotropic background in classical general relativity. The solution procedure is adopted in a model-independent way (or the cosmological parametrization). A simple parametrization of the Hubble parameter (H) as a function of cosmic time t is considered which yields an exponential type of evolution of the scale factor (a) and also shows a negative value of deceleration parameter at the present time with a signature flip from early deceleration to late acceleration. Cosmological dynamics of the model obtained have been discussed illustratively for different phases of the evolution of the universe. The evolution of different cosmological parameters is shown graphically for flat and closed cases of Friedmann–Lemaitre–Robertson–Walker (FLRW) spacetime for the presented model (open case is incompatible to the present scenario). We have also constrained our model parameters with the updated (36 points) observational Hubble dataset.

Anisotropic Dark Energy Cosmological Model with Cosmic Strings

2020 ◽  
Author(s):  
T. Vinutha ◽  
V.U.M. Rao ◽  
Molla Mengesha
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Cosmological Model ◽  
State Parameter ◽  
Accelerated Expansion ◽  
Physical Parameters ◽  
Type I ◽  
Field Equations ◽  
Eos Parameter ◽  
Phantom Divide

The present study deals with a spatially homogeneous locally rotationally symmetric (LRS) Bianchi type-I dark energy cosmological model containing one dimensional cosmic string fluid source. The Einstein's field equations are solved by using a relation between the metric potentials and hybrid expansion law of average scale factor. We discuss accelerated expansion of our model through equation of state (ωde) and deceleration parameter (q). We observe that in the evolution of our model, the equation of state parameter starts from matter dominated phase ωde > -1/3 and ultimately attains a constant value in quintessence region (-1 < ωde < -1/3). The EoS parameter of the model never crosses the phantom divide line (ωde = 1). These facts are consistent with recent observations. We also discuss some other physical parameters.

ENTROPY CORRECTED HOLOGRAPHIC DARK ENERGY f(T) GRAVITY MODEL

2014 ◽  
Vol 29 (02) ◽  
pp. 1450015 ◽  
Author(s):  
M. SHARIF ◽  
SHAMAILA RANI
Keyword(s):  
Dark Energy ◽  
Equation Of State ◽  
Phase Plane ◽  
Holographic Dark Energy ◽  
Cosmological Parameters ◽  
Accelerated Expansion ◽  
Statefinder Parameters ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Evolution Trajectory

This paper is devoted to study the power-law entropy corrected holographic dark energy (ECHDE) model in the framework of f(T) gravity. We assume infrared (IR) cutoff in terms of Granda–Oliveros (GO) length and discuss the constructed f(T) model in interacting as well as in non-interacting scenarios. We explore some cosmological parameters like equation of state (EoS), deceleration, statefinder parameters as well as ωT–ωT′ analysis. The EoS and deceleration parameters indicate phantom behavior of the accelerated expansion of the universe. It is mentioned here that statefinder trajectories represent consistent results with ΛCDM limit, while evolution trajectory of ωT–ωT′ phase plane does not approach to ΛCDM limit for both interacting and non-interacting cases.

scholarly journals Consistency Conditions of f(R,G)-Gravity Field Equations for Bianchi-Type III Metric

2021 ◽  
pp. 29-41
Author(s):  
Selçuk Güler ◽  
Ertan Güdekli
Keyword(s):  
Perfect Fluid ◽  
Bianchi Type ◽  
Energy Content ◽  
Anisotropic Universe ◽  
Field Equations ◽  
Consistency Conditions ◽  
Type Iii ◽  
Barotropic Equation ◽  
The Universe ◽  
Matter Energy

In this paper, we study the -gravitation theory under the assumption that the standard matter-energy content of the universe is a perfect fluid with linear barotropic equation of state within the framework of Bianchi-Type III model from the class of homogeneous and anisotropic universe models. However, whether such a restriction lead to any contradictions or inconsistencies in the field equations will create an issue that needs to be examined. Under the effective fluid approach, we will be concerned mainly the field equations in an orthonormal tetrad framework with an equimolar and examined the situation of establishing the functional form of  together with the scale factors, which are their solutions. Unlike similar studies, which are very few in the literature, instead of assuming preliminary solutions, we determined the consistency conditions of the field equations by assuming the matter energy content of the universe as an isotropic perfect fluid for Bianchi-Type III.

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