Power law inflation with anisotropic fluid in Lyra’s manifold

2017 ◽  
Vol 95 (8) ◽  
pp. 748-752 ◽  
Author(s):  
S. Surendra Singh ◽  
Y. Bembem Devi ◽  
M. Saratchandra Singh
Keyword(s):  
Power Law ◽  
Bianchi Type ◽  
Anisotropic Fluid ◽  
Type I ◽  
Field Equations ◽  
Volumetric Expansion ◽  
Lyra’S Manifold ◽  
Rotationally Symmetric ◽  
Age Of The Universe ◽  
The Universe

Field equations of the locally rotationally symmetric (LRS) Bianchi type-I metric with anisotropic fluid are constructed within the framework of Lyra’s manifold. Power-law volumetric expansion is used to obtain exact solutions of the models for constant and time-dependent displacement field. We discuss the asymptotic behaviors of the derived models, anisotropic behavior of the fluid, expansion parameter, and the evolution of the model with the age of the universe.

Evolution of anisotropic cosmic models in f(R,ϕ) gravity

2018 ◽  
Vol 27 (12) ◽  
pp. 1850115 ◽  
Author(s):  
M. Zubair ◽  
Farzana Kousar ◽  
Saira Waheed
Keyword(s):  
Scalar Field ◽  
Power Law ◽  
Bianchi Type ◽  
Scalar Potential ◽  
Anisotropic Fluid ◽  
Type I ◽  
Field Equations ◽  
Eos Parameter ◽  
Free Parameters ◽  
Physical Quantities

In this paper, we will discuss cosmological models using Bianchi type I for anisotropic fluid in [Formula: see text] theory of gravity which involves scalar potential. For this purpose, we consider power law assumptions of coupling function and scalar field along with the proportionality condition of expansion and shear scalars. We choose two [Formula: see text] models and obtain exact solutions of field equations in both cases. For these constructed models, the behavior of different physical quantities like EoS parameter, self-interacting potential as well as deceleration and skewness parameters are explored and illustrated graphically for the feasible ranges of free parameters. It is concluded that anisotropic fluid approaches isotropy in later cosmic times for both models.

The Mimetic Matter in LRS Bianchi Type-I Model

2021 ◽  
Author(s):  
Ertan Gudekli ◽  
E. Demir
Keyword(s):  
Bianchi Type ◽  
State Parameter ◽  
Relativity Theory ◽  
Type I ◽  
Field Equations ◽  
Bianchi Type I ◽  
Rotationally Symmetric ◽  
Bianchi Type I Universe ◽  
Expansion Of The Universe ◽  
The Universe

This paper deals with the Locally rotationally symmetric (LRS) Bianchi type-I universe model in Mimetic Gravity Theory assuming it an extended form of General Relativity Theory. It was proclaimed as a conformal transformation of the Einstein-Hilbert action from Einstein frame to Jordon frame. At the outset, we have proposed a potential function on account of clarifying the expansion of our universe by considering the general solutions of the field equations that originate from the action of the theory including the Lagrange multipliers. Lastly, after having been achieved the general equation of the state parameter ω, we discussed whether the result corresponds to some fluids illuminating the expansion of the Universe or not.

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 Mixed fluid cosmological model in f(R, T) gravity

2020 ◽  
Vol 98 (11) ◽  
pp. 1015-1022 ◽  
Author(s):  
Parbati Sahoo ◽  
Barkha Taori ◽  
K.L. Mahanta
Keyword(s):  
Cosmological Model ◽  
Bianchi Type ◽  
Type I ◽  
Time Varying ◽  
Eos Parameter ◽  
Barotropic Fluid ◽  
Rotationally Symmetric ◽  
Expansion Of The Universe ◽  
The Universe ◽  
Mixed Fluid

We construct a locally rotationally symmetric (LRS) Bianchi type-I cosmological model in f(R, T) theory of gravity when the source of gravitation is a mixture of barotropic fluid and dark energy (DE) by employing a time-varying deceleration parameter. We observe through the behavior of the state finder parameters (r, s) that our model begins from the Einstein static era and goes to ΛCDM era. The equation of state (EOS) parameter (ωd) for DE varies from the phantom (ω < –1) phase to quintessence (ω > –1) phase, which is consistent with observational results. It is found that the discussed model can reproduce the current accelerating phase of the expansion of the universe.

scholarly journals Bianchi type–I Model with Time Varying Λ and G: The Generalized Solution

2020 ◽  
Vol 29 (1) ◽  
pp. 89-93
Author(s):  
Alnadhief H. A. Alfedeel
Keyword(s):  
Analytical Solution ◽  
Bianchi Type ◽  
Generalized Solution ◽  
Type I ◽  
Time Varying ◽  
Field Equations ◽  
Geometric Function ◽  
Varying Λ ◽  
The Universe ◽  
Average Scale Factor

AbstractIn this paper, we have investigated the homogeneous and anisotropic Bianchi type–I cosmological model with a time-varying Newtonian and cosmological constant. We have analytically solved Einstein’s field equations (EFEs) in the presence of a stiff-perfect fluid. We show that the analytical solution for the average scale factor for the generalized Friedman equation involves the hyper-geometric function. We have studied the physical and kinematical quantities of the model, and it is found that the universe becomes isotropic at late times.

Bianchi type I Universe: An extension of ΛCDM model

2021 ◽  
pp. 2150069
Author(s):  
Rajendra Prasad ◽  
Lalit Kumar Gupta ◽  
A. Beesham ◽  
G. K. Goswami ◽  
Anil Kumar Yadav
Keyword(s):  
Bianchi Type ◽  
Hubble Constant ◽  
Model Parameters ◽  
Constant Density ◽  
Data Sets ◽  
Type I ◽  
Data Set ◽  
Bianchi Type I ◽  
Age Of The Universe ◽  
The Universe

In this paper, we investigate a Bianchi type I exact Universe by taking into account the cosmological constant as the source of energy at the present epoch. We have performed a [Formula: see text] test to obtain the best fit values of the model parameters of the Universe in the derived model. We have used two types of data sets, viz., (i) 31 values of the Hubble parameter and (ii) the 1048 Pantheon data set of various supernovae distance moduli and apparent magnitudes. From both the data sets, we have estimated the current values of the Hubble constant, density parameters [Formula: see text] and [Formula: see text]. The dynamics of the deceleration parameter shows that the Universe was in a decelerating phase for redshift [Formula: see text]. At a transition redshift [Formula: see text], the present Universe entered an accelerating phase of expansion. The current age of the Universe is obtained as [Formula: see text] Gyrs. This is in good agreement with the value of [Formula: see text] calculated from the Plank collaboration results and WMAP observations.

HOMOGENEOUS ANISOTROPIC COSMOLOGICAL MODELS WITH VISCOUS FLUID AND HEAT FLOW IN LYRA'S GEOMETRY

2009 ◽  
Vol 24 (23) ◽  
pp. 1847-1856 ◽  
Author(s):  
SHRI RAM ◽  
M. K. VERMA ◽  
MOHD ZEYAUDDIN
Keyword(s):  
Power Law ◽  
Bianchi Type ◽  
Big Bang ◽  
Field Equations ◽  
Type Singularity ◽  
Exponential Expansion ◽  
Imperfect Fluid ◽  
Lyra’S Geometry ◽  
Type V ◽  
The Universe

In this paper, a spatially homogeneous and anisotropic Bianchi type V model filled with an imperfect fluid with both viscosity and heat conduction is investigated within the framework of Lyra's geometry. Exact solutions of the field equations are obtained by applying a special law of variation for Hubble's parameter which yields a constant value of the deceleration parameter. Two different physically viable models of the universe are presented in two types of cosmologies, one with power-law expansion and other one with exponential expansion. Cosmological model with power-law expansion has an initial big-bang type singularity at t = 0 whereas the model with exponential expansion has a singularity in the infinite past. The physical and dynamical properties of the models are discussed.

Probing kinematics and fate of Bianchi type I universe in Brans–Dicke theory

2020 ◽  
Vol 35 (21) ◽  
pp. 2050174
Author(s):  
Nishant Singla ◽  
Anil Kumar Yadav ◽  
M. K. Gupta ◽  
G. K. Goswami ◽  
Rajendra Prasad
Keyword(s):  
Observational Data ◽  
Bianchi Type ◽  
Statistical Test ◽  
Data Sets ◽  
Type I ◽  
Bianchi Type I Universe ◽  
Age Of The Universe ◽  
Best Fit ◽  
The Universe ◽  
Good Agreement

In this paper, we examine the existence of Bianch type I Brans–Dicke universe by performing statistical test from [Formula: see text] and SN Ia observational data sets. We find that anisotropic Brans-Dicke ([Formula: see text] BD) model provides a reasonable fit with observational data. In addition to [Formula: see text], we also use Akaike information creation (AIC) and Bayes information creation (BIC) to determine the values of best fit parameters. The model under consideration represents a transitioning universe from early decelerating phase to current accelerating phase. We obtain the present age of the universe as 13.732 Gyrs, which is in good agreement with WMAP observations. The physical behavior of particle horizon and [Formula: see text] parameter of the derived model are also discussed.

scholarly journals Bianchi Type I Cosmological Models with Expansion Driven by Particle Creation

2018 ◽  
Author(s):  
Kalyani Desikan
Keyword(s):  
Bianchi Type ◽  
Energy Momentum Tensor ◽  
Particle Creation ◽  
Momentum Tensor ◽  
Conservation Equation ◽  
Type I ◽  
Field Equations ◽  
Bianchi Type I ◽  
Energy Conservation Equation ◽  
The Universe

A study of Bianchi Type I cosmological model is undertaken in the framework of creation of particles. To accommodate the creation of new particles, the universe is regarded as an Open thermodynamical system. The energy conservation equation is modified with the incorporation of a creation pressure in the energy momentum tensor. Exact solutions of the field equations are obtained (i) for a particular choice of the particle creation function and (ii) by considering the deceleration parameter to be constant. In the first model the behavior of the solution at late times is investigated. The physical aspects of the model have also been discussed. In the case of the second model we have restricted our analysis to the power law behaviour for the average scale factor. This leads to a particular form for the particle creation function. The behavior of the solution is investigated and the physical aspects of the model have also been discussed for the matter dominated era.

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.

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