AN EXACT BIANCHI TYPE-I COSMOLOGICAL MODEL IN LYRA'S MANIFOLD

2008 ◽  
Vol 23 (06) ◽  
pp. 813-822 ◽  
Author(s):  
SURESH KUMAR ◽  
C. P. SINGH
Keyword(s):  
Bianchi Type ◽  
Type I ◽  
Hubble’S Parameter ◽  
Field Equations ◽  
Bianchi Type I ◽  
Lyra’S Manifold ◽  
Type Ia ◽  
Lyra’S Geometry ◽  
Spatially Homogeneous ◽  
Ia Supernovae

A spatially homogeneous and anisotropic Bianchi type-I space–time has been studied within the framework of Lyra's geometry. Exact solutions of the Einstein's field equations have been obtained with a time dependent gauge function by using a special law of variation for Hubble's parameter that yields a constant value of deceleration parameter. It has been found that the solutions generalize the solutions obtained by Rahaman et al. [Astrophys. Space Sci.299, 211 (2005)] and are consistent with the recent observations of type Ia supernovae. A detailed study of physical and kinematical properties of the model has been carried out.

scholarly journals LRS Bianchi type-I cosmological model with constant deceleration parameter in f(R,T) gravity

2017 ◽  
Vol 14 (11) ◽  
pp. 1750158 ◽  
Author(s):  
Binaya K. Bishi ◽  
S. K. J. Pacif ◽  
P. K. Sahoo ◽  
G. P. Singh
Keyword(s):  
Cosmological Model ◽  
Deceleration Parameter ◽  
Hubble Parameter ◽  
Bianchi Type ◽  
Specific Model ◽  
Type I ◽  
Hubble’S Parameter ◽  
Constant Deceleration Parameter ◽  
Bianchi Type I ◽  
Spatially Homogeneous

A spatially homogeneous anisotropic LRS Bianchi type-I cosmological model is studied in [Formula: see text] gravity with a special form of Hubble's parameter, which leads to constant deceleration parameter. The parameters involved in the considered form of Hubble parameter can be tuned to match, our models with the [Formula: see text]CDM model. With the present observed value of the deceleration parameter, we have discussed physical and kinematical properties of a specific model. Moreover, we have discussed the cosmological distances for our model.

On a Bianchi type-I space-time with bulk viscosity in f(R,T) gravity

2021 ◽  
Author(s):  
M. Koussour ◽  
M. Bennai
Keyword(s):  
Deceleration Parameter ◽  
Bianchi Type ◽  
Momentum Tensor ◽  
Energy Conditions ◽  
Type I ◽  
Field Equations ◽  
Bulk Fluid ◽  
Bianchi Type I ◽  
Deceleration Phase ◽  
Spatially Homogeneous

In this paper, we present a spatially homogeneous and anisotropic Bianchi type-I cosmological model with a viscous bulk fluid in [Formula: see text] gravity where [Formula: see text] and [Formula: see text] are the Ricci scalar and trace of the energy-momentum tensor, respectively. The field equations are solved explicitly using the hybrid law of the scale factor, which is related to the average Hubble parameter and gives a time-varying deceleration parameter (DP). We found the deceleration parameter describing two phases in the universe, the early deceleration phase [Formula: see text] and the current acceleration phase [Formula: see text]. We have calculated some physical and geometric properties and their graphs, whether in terms of time or redshift. Note that for our model, the bulk viscous pressure [Formula: see text] is negative and the energy density [Formula: see text] is positive. The energy conditions and the [Formula: see text] analysis for our spatially homogeneous and anisotropic Bianchi type-I model are also discussed.

scholarly journals Interaction of Bianchi type-I anisotropic cloud string cosmological model universe with electromagnetic field

2020 ◽  
Vol 17 (09) ◽  
pp. 2050133
Author(s):  
Kangujam Priyokumar Singh ◽  
Mahbubur Rahman Mollah ◽  
Rajshekhar Roy Baruah ◽  
Meher Daimary
Keyword(s):  
Electromagnetic Field ◽  
Cosmological Model ◽  
Bianchi Type ◽  
Physical Parameters ◽  
Type I ◽  
Field Equations ◽  
Rest Energy ◽  
Model Universe ◽  
Bianchi Type I ◽  
String Cosmological Model

Here, we have investigated the interaction of Bianchi type-I anisotropic cloud string cosmological model universe with electromagnetic field in the context of general relativity. In this paper, the energy-momentum tensor is assumed to be the sum of the rest energy density and string tension density with an electromagnetic field. To obtain exact solution of Einstein’s field equations, we take the average scale factor as an integrating function of time. Also, the dynamics and significance of various physical parameters of model are discussed.

BIANCHI TYPE V COSMOLOGICAL MODELS WITH PERFECT FLUID AND HEAT CONDUCTION IN LYRA'S GEOMETRY

2008 ◽  
Vol 23 (31) ◽  
pp. 4991-5005 ◽  
Author(s):  
SHRI RAM ◽  
MOHD. ZEYAUDDIN ◽  
C. P. SINGH
Keyword(s):  
Perfect Fluid ◽  
Bianchi Type ◽  
Displacement Vector ◽  
Hubble’S Parameter ◽  
Field Equations ◽  
Constant Deceleration Parameter ◽  
Displacement Vector Field ◽  
Lyra’S Geometry ◽  
Type V ◽  
Bianchi Type V

The field equations within the framework of Lyra's geometry with a time-dependent displacement vector field for a Bianchi type-V space–time filled with a perfect fluid and heat flow are presented. Two different classes of physically viable solutions are obtained by using a special law of variation for the generalized mean Hubble's parameter which correspond to singular and nonsingular models with constant deceleration parameter. These models are found to be consistent with the observations on the present day universe. Some thermodynamical relations are studied. The physical and kinematical behaviors of the models are also discussed.

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.

scholarly journals Bianchi Type-I Universe with Cosmological Constant and Quadratic Equation of State inf(R,T)Modified Gravity

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
G. P. Singh ◽  
Binaya K. Bishi
Keyword(s):  
Equation Of State ◽  
Cosmological Constant ◽  
Modified Gravity ◽  
Bianchi Type ◽  
Quadratic Equation ◽  
Type I ◽  
Field Equations ◽  
Bianchi Type I ◽  
Bianchi Type I Universe ◽  
Quadratic Equation Of State

This paper deals with the study of Bianchi type-I universe in the context off(R,T)gravity. Einstein’s field equations inf(R,T)gravity have been solved in the presence of cosmological constantΛand quadratic equation of state (EoS)p=αρ2-ρ, whereα≠0is a constant. Here, we have discussed two classes off(R,T)gravity; that is,f(R,T)=R+2f(T)andf(R,T)=f1(R)+f2(T). A set of models has been taken into consideration based on the plausible relation. Also, we have studied some physical and kinematical properties of the models.

scholarly journals LRS Bianchi type-I Universe with anisotropic dark energy and special form of deceleration parameter in f (R, T) gravity

2018 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Rajesh Wankhade ◽  
A.S. Bansod
Keyword(s):  
Deceleration Parameter ◽  
Special Form ◽  
Bianchi Type ◽  
Momentum Tensor ◽  
Physical Aspect ◽  
Type I ◽  
Field Equations ◽  
Bianchi Type I ◽  
Anisotropic Dark Energy ◽  
Bianchi Type I Universe

In this paper, LRS Bianchi type-I space-time is considered in the presence of perfect fluid source in the frame work of  gravity (Harko et al. in Phys.Rev. D 84:024020, 2011) where is an arbitrary function of Ricci scalar  and trace of the energy momentum tensor . The Einstein’s field equations have been solved by taking into account the special form of deceleration parameter (Singha A., Debnath U.: Int.J. Theor. Phys.48, 2009). We observe that in f (R, T) gravity, an extra acceleration is always present due to coupling between matter and geometry. The geometrical and physical aspect of the model is also studied.

scholarly journals Approximate Solutions of the LRS Bianchi Type-I Cosmological Model

Symmetry ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 403
Author(s):  
Yihu Feng ◽  
Lei Hou
Keyword(s):  
Cosmological Model ◽  
Homotopy Perturbation Method ◽  
Bianchi Type ◽  
Approximate Solutions ◽  
Space Time ◽  
Type I ◽  
Main Field ◽  
Field Equations ◽  
Bianchi Type I ◽  
Homotopy Perturbation

In this current study, we explore the modified homogeneous cosmological model in the background of LRS Bianchi type-I space–time. For this purpose, we employ the Homotopy Perturbation Method (HPM). HPM is an analytical-based method. Further, we calculated the main field equations of the cosmological model LRS Bianchi type-I space–time. Furthermore, we discuss the necessary calculations of HPM. Therefore, we investigate the analytical solution of our problem by adopting HPM. In this response, we discuss five different values of parameter n. We also give a brief discussion about solutions. The main purpose of this study is to apply the application of HPM in the cosmological field.

Phase transition of LRS Bianchi type-I cosmological model in f(R,T) gravity

2020 ◽  
Vol 17 (12) ◽  
pp. 2050187
Author(s):  
R. K. Tiwari ◽  
D. Sofuoğlu ◽  
V. K. Dubey
Keyword(s):  
Cosmological Model ◽  
Bianchi Type ◽  
Early Time ◽  
Momentum Tensor ◽  
Late Time ◽  
Type I ◽  
Field Equations ◽  
Bianchi Type I ◽  
Accelerating Expansion ◽  
Acceleration Of The Universe

In this work, LRS Bianchi type-I cosmological model with perfect fluid source in [Formula: see text] gravity theory, where [Formula: see text] is the Ricci scalar and [Formula: see text] is the trace of the stress energy-momentum tensor, has been studied in order to investigate early time deceleration and late time acceleration of the universe. By proposing a new special form of time-varying deceleration parameter in terms of Hubble parameter, the exact solution of the field equations has been obtained. The physical and geometric quantities of the model have been derived and their evolution has been discussed. Our model has an initial singularity and initially exhibits decelerating expansion and transits to accelerating expansion phase at last eras. The nature of the matter source of the model is consistent with the standard model in frame of the structure formation.

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