SOME COSMOLOGICAL MODELS IN SCALAR–TENSOR THEORIES

A class of non-static solutions to the Einstein field equations has been investigated in the context of Bianchi type-V spacetime in a family of scalar–tensor theories in the presence as well as absence of the magnetic field. The physical and kinematical behaviors of the models have been discussed. The energy conditions of the models have also been verified.

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SOME BIANCHI TYPE-V COSMOLOGICAL MODELS IN BRANS–DICKE THEORY

International Journal of Modern Physics A ◽

10.1142/s0217751x10049761 ◽

2010 ◽

Vol 25 (18n19) ◽

pp. 3817-3824 ◽

Cited By ~ 7

Author(s):

J. K. SINGH

Keyword(s):

Magnetic Field ◽

Bianchi Type ◽

Cosmological Models ◽

Energy Conditions ◽

Type V ◽

The Magnetic Field ◽

Bianchi Type V

The Bianchi type-V cosmological models have been investigated in the context of Brans–Dicke theory in the presence as well as absence of the magnetic field. The physical and kinematical behaviors of the models have been discussed. The energy conditions of the models have also been examined.

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SOME BIANCHI TYPE COSMOLOGICAL MODELS IN LYRA GEOMETRY

International Journal of Modern Physics A ◽

10.1142/s0217751x08041530 ◽

2008 ◽

Vol 23 (30) ◽

pp. 4925-4931 ◽

Cited By ~ 6

Author(s):

J. K. SINGH

Keyword(s):

Bianchi Type ◽

Lyra Geometry ◽

Energy Conditions ◽

Geometrical Parameters ◽

Einstein Field Equations ◽

Field Equations ◽

Massive Scalar Field ◽

Normal Gauge ◽

Type V ◽

Bianchi Type V

A class of nonstatic solutions for Einstein field equations has been investigated in the context of Bianchi type-V space–time in the theory based on Lyra's geometry in Gauss normal gauge and in the presence of an attractive massive scalar field. The results have been studied through various physical and geometrical parameters. The energy conditions of the model have also been verified.

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Bianchi type-V cosmology with magnetized anisotropic dark energy

Canadian Journal of Physics ◽

10.1139/cjp-2016-0777 ◽

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.

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Viability of Bianchi type V universe in f(R,T) = f1(R) + f2(R)f3(T) gravity

International Journal of Geometric Methods in Modern Physics ◽

10.1142/s021988782050111x ◽

2020 ◽

Vol 17 (07) ◽

pp. 2050111

Author(s):

Lokesh Kumar Sharma ◽

Benoy Kumar Singh ◽

Anil Kumar Yadav

Keyword(s):

Bianchi Type ◽

Hubble Constant ◽

Lagrangian Model ◽

Energy Conditions ◽

Physical Parameters ◽

Field Equations ◽

Eos Parameter ◽

Bianchi Type V Universe ◽

Type V ◽

Bianchi Type V

In this paper, we examine the viability of Bianchi type V universe in [Formula: see text] theory of gravitation. To solve the field equations, we have considered the power law for scale factor and constructed a singular Lagrangian model which is based on the coupling between Ricci scalar [Formula: see text] and trace of energy–momentum tensor [Formula: see text]. We find the constraints on Hubble constant [Formula: see text] and free parameter [Formula: see text] with 46 observational Hubble dataset and obtain pretty satisfactory results. The physical features of the model and transitional behavior of equation of state (EOS) parameter are analyzed. We examine the nature of physical parameters and validity of energy conditions as well as stability condition. We also present the Om[Formula: see text] and statefinder diagnostic analysis for the derived model.

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THE BIANCHI TYPE V MAGNETIZED STRING DUST COSMOLOGICAL MODEL IN GENERAL RELATIVITY

International Journal of Modern Physics D ◽

10.1142/s0218271807011073 ◽

2007 ◽

Vol 16 (11) ◽

pp. 1769-1781 ◽

Cited By ~ 11

Author(s):

RAJ BALI ◽

SHILPI JAIN

Keyword(s):

Magnetic Field ◽

Electrical Conductivity ◽

General Relativity ◽

Cosmological Model ◽

Bianchi Type ◽

Fluid Distribution ◽

Type V ◽

The Magnetic Field ◽

Bianchi Type V ◽

Nonvanishing Component

The Bianchi type V magnetized string dust cosmological model for perfect fluid distribution is investigated. We assume that the magnetic field is along the x direction, so F23 is the only nonvanishing component of Fij. We also find that F14 = 0 = F24 = F34 due to the assumption of infinite electrical conductivity. The behavior of the model in the presence and the absence of a magnetic field is also discussed.

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Bianchi type-V solutions with varying G and Λ: The general case

International Journal of Geometric Methods in Modern Physics ◽

10.1142/s0219887820500760 ◽

2020 ◽

Vol 17 (06) ◽

pp. 2050076

Author(s):

Alnadhief H. A. Alfedeel ◽

Amare Abebe

Keyword(s):

Bianchi Type ◽

Einstein Field Equations ◽

Field Equations ◽

Energy Models ◽

Runge Kutta Method ◽

Gravitational And Cosmological Constants ◽

Phantom Dark Energy ◽

Type V ◽

Cosmological Constants ◽

Bianchi Type V

The homogeneous and anisotropic Bianchi type-V cosmological model with variable gravitational and cosmological “constants” with a general (nonstiff) perfect fluid is investigated. The Einstein field equations (EFEs) are numerically integrated with the fourth-order Runge–Kutta method for different values of [Formula: see text] and [Formula: see text] parameters of quantum fields in a curved and expanding background. Three realistic models, namely matter, radiation and phantom dark energy models are also discussed. In all these models, it was found that the cosmological “constant” decreases with time, whereas the gravitational “constant” increases over time. It is shown that the universe in these models becomes isotropic at late times.

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Some Bianchi type-V accelerating cosmological models in f(R,T) = f1(R) + f2(T) formalism

International Journal of Geometric Methods in Modern Physics ◽

10.1142/s0219887820501595 ◽

2020 ◽

Vol 17 (10) ◽

pp. 2050159

Author(s):

Vinod Kumar Bhardwaj ◽

Anil Kumar Yadav

Keyword(s):

Phase Transition ◽

Bianchi Type ◽

Cosmological Models ◽

Accelerated Expansion ◽

Field Equations ◽

Geometrical Properties ◽

Energy Scenario ◽

Type V ◽

The Universe ◽

Bianchi Type V

In this paper, we have studied the transition and physical behavior of Bianchi type-V cosmological models within the formalism of [Formula: see text] gravity. To obtain the solution of field equations and phase transition of universe consistent with recent cosmological observations, time varying deceleration parameters are considered. In this paper, we used two different scale factors of the form (i) [Formula: see text], where [Formula: see text] are constants. Here, for [Formula: see text] the universe shows transition with accelerated expansion. (ii) [Formula: see text], where [Formula: see text] and [Formula: see text] are constants. For [Formula: see text], the universe achieves a phase transition from early decelerating to current accelerating phase. The model I initially starts with quintessence scenario ([Formula: see text]) and ends up with ([Formula: see text]) as a model with cosmological constant ([Formula: see text]) as [Formula: see text]. Model II, for [Formula: see text] indicates the phantom energy scenario and for [Formula: see text], the model starts with quintessence [Formula: see text] and ends with vacuum energy scenario. A point type singularity has been observed in the derived model I. Some physical and geometrical properties of the models have been established and discussed to derive the validity of models with respect to recent astrophysical observations.

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