scholarly journals EFFECTS OF ELECTROMAGNETIC FIELD ON THE DYNAMICS OF BIANCHI TYPE VI0UNIVERSE WITH ANISOTROPIC DARK ENERGY

2010 ◽  
Vol 19 (12) ◽  
pp. 1957-1972 ◽  
Author(s):  
M. SHARIF ◽  
M. ZUBAIR
Keyword(s):  
Electromagnetic Field ◽  
Dark Energy ◽  
Bianchi Type ◽  
Anisotropic Fluid ◽  
Einstein Field Equations ◽  
Anisotropic Behavior ◽  
Field Equations ◽  
Future Evolution ◽  
Anisotropic Dark Energy ◽  
The Universe

Spatially homogeneous and anisotropic Bianchi type VI0cosmological models with cosmological constant are investigated in the presence of anisotropic dark energy. We examine the effects of electromagnetic field on the dynamics of the universe and anisotropic behavior of dark energy. The law of variation of the mean Hubble parameter is used to find exact solutions of the Einstein field equations. We find that electromagnetic field promotes anisotropic behavior of dark energy which becomes isotropic for future evolution. It is concluded that the isotropic behavior of the universe model is seen even in the presence of electromagnetic field and anisotropic fluid.

scholarly journals ACCELERATING DARK ENERGY MODELS IN BIANCHI TYPE-V SPACETIME

2011 ◽  
Vol 26 (30) ◽  
pp. 2261-2275 ◽  
Author(s):  
ANIRUDH PRADHAN ◽  
HASSAN AMIRHASHCHI
Keyword(s):  
Dark Energy ◽  
Bianchi Type ◽  
Late Time ◽  
Field Equations ◽  
Future Evolution ◽  
New Exact Solutions ◽  
Spatially Homogeneous ◽  
Type V ◽  
The Universe ◽  
Bianchi Type V

Some new exact solutions of Einstein's field equations in a spatially homogeneous and anisotropic Bianchi type-V spacetime with minimally interaction of perfect fluid and dark energy components have been obtained. To prevail the deterministic solution we choose the scale factor [Formula: see text], which yields a time-dependent deceleration parameter (DP), representing a model which generates a transition of the universe from the early decelerating phase to the recent accelerating phase. We find that for n ≥ 1, the quintessence model is reproducible with present and expected future evolution of the universe. The other models (for n < 1), we observe the phantom scenario. The quintessence as well as phantom models approach to isotropy at late time. For different values of n, we can generate a class of physically viable DE models. The cosmic jerk parameter in our descended model is also found to be in good concordance with the recent data of astrophysical observations under appropriate condition. The physical and geometric properties of spatially homogeneous and anisotropic cosmological models are discussed.

Interaction of anisotropic dark energy fluid with perfect fluid in the presence of cosmological term Λ

2018 ◽  
Vol 33 (15) ◽  
pp. 1850084
Author(s):  
S. Surendra Singh
Keyword(s):  
Dark Energy ◽  
Energy Density ◽  
Anisotropic Fluid ◽  
Type I ◽  
Field Equations ◽  
Dark Energy Density ◽  
Anisotropic Dark Energy ◽  
Age Of The Universe ◽  
Rotating Universe ◽  
The Universe

Considering the locally rotationally symmetric (LRS) Bianchi type-I metric with cosmological constant [Formula: see text], Einstein’s field equations are discussed based on the background of anisotropic fluid. We assumed the condition A = B[Formula: see text] for the metric potentials A and B, where m is a positive constant to obtain the viable model of the Universe. It is found that [Formula: see text] is positive and inversely proportional to time. The values of matter-energy density [Formula: see text], dark energy density [Formula: see text] and deceleration parameter q are found to be consistent with the values of WMAP observations. State finder parameters and anisotropic deviation parameter are also investigated. It is also observed that the derived model is an accelerating, shearing and non-rotating Universe. Some of the asymptotic and geometrical behaviors of the derived models are investigated with the age of the Universe.

scholarly journals Generalized Phenomenological Models of Dark Energy

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Prasenjit Paul ◽  
Rikpratik Sengupta
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Energy Density ◽  
Cosmological Constant ◽  
Phenomenological Models ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Free Parameters ◽  
The Universe ◽  
Matter Energy

It was first observed at the end of the last century that the universe is presently accelerating. Ever since, there have been several attempts to explain this observation theoretically. There are two possible approaches. The more conventional one is to modify the matter part of the Einstein field equations, and the second one is to modify the geometry part. We shall consider two phenomenological models based on the former, more conventional approach within the context of general relativity. The phenomenological models in this paper consider a Λ term firstly a function of a¨/a and secondly a function of ρ, where a and ρ are the scale factor and matter energy density, respectively. Constraining the free parameters of the models with the latest observational data gives satisfactory values of parameters as considered by us initially. Without any field theoretic interpretation, we explain the recent observations with a dynamical cosmological constant.

Evolution of the Universe with two rotating fluids

2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040042
Author(s):  
V. F. Panov ◽  
O. V. Sandakova ◽  
E. V. Kuvshinova ◽  
D. M. Yanishevsky
Keyword(s):  
General Relativity ◽  
Dark Energy ◽  
Scalar Field ◽  
Bianchi Type ◽  
Relativity Theory ◽  
Anisotropic Fluid ◽  
Rotating Fluids ◽  
General Relativity Theory ◽  
Exponential Expansion ◽  
The Universe

An anisotropic cosmological model with expansion and rotation and the Bianchi type IX metric has been constructed within the framework of general relativity theory. The first inflation stage of the Universe filled with a scalar field and an anisotropic fluid is considered. The model describes the Friedman stage of cosmological evolution with subsequent transition to accelerated exponential expansion observed in the present epoch. The model has two rotating fluids: the anisotropic fluid and dust-like fluid. In the approach realized in the model, the anisotropic fluid describes the rotating dark energy.

ANISOTROPIC SELF-SIMILAR COSMOLOGICAL MODEL WITH DARK ENERGY

2006 ◽  
Vol 15 (07) ◽  
pp. 991-999 ◽  
Author(s):  
P. R. PEREIRA ◽  
M. F. A. DA SILVA ◽  
R. CHAN
Keyword(s):  
Dark Energy ◽  
Energy Conditions ◽  
Anisotropic Fluid ◽  
Accelerating Universe ◽  
Spherically Symmetric ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Self Similarity ◽  
Normal Matter ◽  
Self Similar

We study space–times having spherically symmetric anisotropic fluid with self-similarity of zeroth kind. We find a class of solutions to the Einstein field equations by assuming a shear-free metric and that the fluid moves along time-like geodesics. The energy conditions, and geometrical and physical properties of the solutions are studied and we find that it can be considered as representing an accelerating universe. At the beginning all the energy conditions were fulfilled but beyond a certain time (a maximum geometrical radius) none of them is satisfied, characterizing a transition from normal matter (dark matter, baryon matter and radiation) to dark energy.

KALUZA–KLEIN COSMOLOGICAL MODELS WITH ANISOTROPIC DARK ENERGY

2011 ◽  
Vol 26 (10) ◽  
pp. 739-750 ◽  
Author(s):  
K. S. ADHAV ◽  
A. S. BANSOD ◽  
R. P. WANKHADE ◽  
H. G. AJMIRE
Keyword(s):  
Dark Energy ◽  
Exact Solutions ◽  
Deceleration Parameter ◽  
Hubble Parameter ◽  
Cosmological Models ◽  
Einstein Field Equations ◽  
Field Equations ◽  
Anisotropic Dark Energy ◽  
The Law ◽  
Kaluza Klein

The exact solutions of the Einstein field equations for dark energy in Kaluza–Klein metric under the assumption on the anisotropy of the fluid are obtained by applying the law of variation of Hubble parameter which yields the constant value of deceleration parameter. The isotropy of the fluid, space and expansion are examined.

scholarly journals Bianchi type-V cosmology with magnetized anisotropic dark energy

2017 ◽  
Vol 95 (3) ◽  
pp. 274-282
Author(s):  
M. Farasat Shamir ◽  
Asad Ali
Keyword(s):  
Magnetic Field ◽  
Dark Energy ◽  
Bianchi Type ◽  
Anisotropic Fluid ◽  
Physical Parameters ◽  
Anisotropic Universe ◽  
Field Equations ◽  
Constant Deceleration Parameter ◽  
Type V ◽  
Bianchi Type V

We study anisotropic universe in the presence of magnetized dark energy. Bianchi type-V cosmological model is considered for this purpose. The energy–momentum tensor consists of anisotropic fluid with uniform magnetic field of energy density ρB. Exact solutions to the field equations are obtained without using conventional assumptions like constant deceleration parameter. In particular, a general solution is obtained that further provides different classes of solutions. Only three cases have been discussed for the present analysis: linear, quadratic, and exponential. Graphical analyses of the solutions are done for all the three classes. The behavior of the model using some important physical parameters is discussed in the presence of magnetic field.

Evaluation of Bianchi type VI0 magnetized anisotropic dark energy models with constant deceleration parameter in bimetric theory of gravitation

2015 ◽  
Vol 24 (02) ◽  
pp. 1550019 ◽  
Author(s):  
M. S. Borkar ◽  
A. Ameen
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Bianchi Type ◽  
Constant Deceleration Parameter ◽  
Exponential Law ◽  
Anisotropic Dark Energy ◽  
Energy Models ◽  
Visible Matter ◽  
Theory Of Gravitation ◽  
The Universe

In this paper, Bianchi type VI0 magnetized anisotropic dark energy models with constant deceleration parameter have been studied by solving the Rosen's field equations in Bimetric theory of gravitation. The models corresponding to power law expansion and exponential law expansion have been evaluated and studied their nature geometrically and physically. It is seen that there is real visible matter (baryonic matter) suddenly appeared only for small interval of time 0.7 ≤ t < 0.7598 and for the remaining whole range of time t, there is dark energy matter in the universe. Our investigations are supported to the observational fact that the usual matter described by known particle theory is about 4% and the dark energy cause the accelerating expansion of the universe and several high precision observational experiments, especially the Wilkinson Microwave Anisotropic Probe (WMAP) satellite experiment (see [C. L. Bennett et al., Astrophys. J. Suppl. Ser. 148 (2003) 1; WMAP Collab. (D. N. Spergel et al.), Astrophys. J. Suppl. Ser. 148 (2003) 175; D. N. Spergel et al., Astrophys. J. Suppl. 170 (2007) 377; WMAP Collab. (E. Komastu et al.), Astrophys. J. Suppl. 180 (2009) 330; WMAP Collab. (G. Hinshaw et al.), Astrophys. J. Suppl. 208 (2013) 19; Plank Collab. (P. A. R. Ade), arXiv:1303.5076; arXiv:1303.5082]) conclude that the dark energy occupies near about 73% of the energy of the universe and dark matter is about 23%. In exponential law of expansion, our model is fully occupied by real visible matter and there is no chance of dark energy and dark matter.

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.

Kantowski–Sachs universe with dark energy fluid and massive scalar field

2020 ◽  
Vol 98 (11) ◽  
pp. 993-998
Author(s):  
K. Deniel Raju ◽  
M.P.V.V. Bhaskara Rao ◽  
Y. Aditya ◽  
T. Vinutha ◽  
D.R.K. Reddy
Keyword(s):  
Dark Energy ◽  
Scalar Field ◽  
Cosmological Parameters ◽  
Accelerated Expansion ◽  
Massive Scalar ◽  
Field Equations ◽  
Massive Scalar Field ◽  
Anisotropic Dark Energy ◽  
Expansion Of The Universe ◽  
The Universe

This study is mainly concerned with a spatially homogeneous and anisotropic Kantowski–Sachs cosmological model with anisotropic dark energy fluid and massive scalar field. We solve the field equations using (i) the shear scalar proportionality to the expansion scalar and (ii) a mathematical condition that is a consequence of the power law between the scalar field and the average scale factor of the universe, and the corresponding dark energy model is presented. The cosmological parameters of the model are computed and discussed, as well as the relevance of its dynamical aspects to the recent scenario of the accelerated expansion of the universe.

Sign in / Sign up

Export Citation Format

Share Document