Kaluza-Klein Cosmological Model Research Articles

Kaluza–Klein cosmological model with strange-quark-matter in f(R,T) theory of gravity

Kaluza–Klein cosmological model with strange-quark-matter in f(R,T) theory of gravity

Kaluza–Klein cosmological model with strange-quark-matter in Lyra geometry

In this paper, we have studied Kaluza–Klein Cosmological Model with strange-quark-matter in Lyra Geometry. To determine the solution of the field equation, we have assumed that scalar expansion [Formula: see text] is proportional to shear scalar [Formula: see text] which leads to [Formula: see text], where [Formula: see text], [Formula: see text] are metric potentials and [Formula: see text] is arbitrary constant. The cosmological parameters are investigated with the help of equation of state strange-quark-matter (SQM), which is [Formula: see text], where [Formula: see text] is Bag constant. We compared the results of general General relativity (GR) and scalar-tensor theory and also discussed the behaviors of some physical parameters.

Kaluza-Klein Cosmological Models with Barotropic Fluid Distribution

Kaluza-Klein cosmological models have been investigated for barotropic fluid distribution with time dependent gravitational constant and cosmological constant in the context of general relativity. We have used Hybrid Expansion Law (HEL), a product of power-law and exponential type of functions, to obtain determinate solutions of the Einstein’s field equations. In this paper, we have mainly discussed the graphical behavior of the results for three different cases of interest in modern cosmology.

Bulk viscous fluid cosmological models in f(R, T) gravity

In the literature, a number of modified theories have been discussed to explain early and late time expansion of the universe. In this context, f(R) gravity (R being the Ricci scalar) is the simplest and most popular modification of general relativity. Other modified theories like f(T) gravity, where T is the torsion has been proposed to overcome many problems in cosmology. Kaluza–Klein cosmological models in f(R, T) theory of gravity are investigated when the source of gravitation is the bulk viscous fluid. In this work, it is considered that the function f(R, T) as f(R,T)=R+2f(T) or f(R,T)=f1(R)+f2(T). Such a choice of the functional f(R, T) leads to an evolving effective cosmological constant Λ, which depends on the stress energy tensor. f1(R) and f2(T) are arbitrary functions of R and T, respectively and f(R, T) = R f(T) may be considered to solve the field equations. We however do not consider the general case, but restrict ourselves to the following form f(R, T) = R + 2f(T), where f(T) is an arbitrary function of the trace of energy-momentum tensor of matter. The term 2f(T) in the gravitational action modified the gravitational interaction between matter and curvature. It is observed that the first case of the model be reduced to effective stiff fluid model of the universe while the second case gives general bulk viscous model of the universe. The exact solutions of the field equations are obtained. Keeping an eye on the accelerating nature of the universe in the present epoch, the dynamics and physical behaviour of the models are discussed.

Bouncing Behavior of Kaluza-Klein Cosmological Model in General Relativity

Bouncing Behavior of Kaluza-Klein Cosmological Model in General Relativity

Kaluza-Klein cosmological model in f ( R , T ) $f(R,T)$ gravity with domain walls

We have investigated the physical behavior of the five dimensional Kaluza-Klein cosmological model in the frame work of $f(R,T)$ theory of gravity in presence of domain walls. Here, $R$ is the Ricci scalar and $T$ is the trace energy tensor. To determine the solution of field equation, we have considered the special law of variation parameter proposed by Berman (Nuovo Cimento 74B:182, 1983) that yields a constant deceleration parameter. Some physical properties of the model are discussed.

Kaluza–Klein cosmological model in f(R, T) gravity with Λ(T)

A class of Kaluza-Klein cosmological models in $f(R,T)$ theory of gravity have been investigated. In the work, we have considered the functional $f(R,T)$ to be in the form $f(R,T)=f(R)+f(T)$ with $f(R)=\lambda R$ and $f(T)=\lambda T$. Such a choice of the functional $f(R,T)$ leads to an evolving effective cosmological constant $\Lambda$ which depends on the stress energy tensor. The source of the matter field is taken to be a perfect cosmic fluid. The exact solutions of the field equations are obtained by considering a constant deceleration parameter which leads two different aspects of the volumetric expansion namely a power law and an exponential volumetric expansion. Keeping an eye on the accelerating nature of the universe in the present epoch, the dynamics and physical behaviour of the models have been discussed. From statefinder diagnostic pair we found that the model with exponential volumetric expansion behaves more like a $\Lambda$CDM model.

Corrigendum to: Kaluza-Klein Cosmological Model, Strange Quark Matter, and Time-Varying Lambda

Article Corrigendum to: Kaluza-Klein Cosmological Model, Strange Quark Matter, and Time-Varying Lambda was published on May 1, 2015 in the journal Zeitschrift für Naturforschung A (volume 70, issue 5).

Kaluza-Klein Type Cosmological Model with Ω–Dependent Cosmological Constant and Big Rip Singularity

In this paper by using the modified EOS of the form p=– ρ–f(ρ) we investigate the evolution of the scale factor in Kaluza-Klein type cosmological model in which cosmological constant is given by the scalar arisen by the contraction of the scale energy tensor. It is shown that the big rip singularity occurs at finite time t = ts by violating null, weak, strong energy condition and satisfying the dominant energy condition for α > 0. For the general case f(ρ) = αρ(β+1/2), it is observed that for β= 1/2 >0,R(t), p(t) and H(t) → ∞ are reached at a finite time ts = 2/b0, where b0 is constant. So again take place big rip singularity at a finite time. However, for β < 0, singularity does not occurs at a finite time in the framework of Kaluza-Klein theory of gravitation.

Kaluza-Klein Anisotropic Magnetized Dark Energy Cosmological Model in Brans-Dicke Theory of Gravitation

We study the spatially homogeneous Kaluza-Klein cosmological model with magnetized anisotropic fluid in the scalar tensor theory of gravitation proposed by Brans-Dicke [1]. Exact solutions of the models are obtained by Volumetric exponential and power law expansion. The Physical behaviors of the models have been discussed using some physical quantities.

Kaluza–Klein Cosmological Model, Strange Quark Matter, and Time-Varying Lambda

In this paper, exact solutions of the Einstein field equations of the Kaluza-Klein cosmological model have been obtained in the presence of strange quark matter. We have considered the timevarying cosmological constant Λ as Λ = αH2 + βR-2, where α and β are free parameters. The solutions are obtained with the help of the equation of state for strange quark matter as per the Bag model, i.e. quark pressure p = 1/3(ρ - 4BC), where BC is Bag’s constant. We also discussed the physical implications of the solutions obtained for the model for different types of universes.

Kaluza-Klein dark energy cosmological model in scale Co-variant Theory of Gravitation

A five dimensional Kaluza-Klein dark energy model with variable EoS parameter is investigated in the scale co-variant theory of gravitation proposed by Canuto et al. (in Phys. Rev. 39:429, 1977) in a five dimensional Kaluza-Klein space-time in the presence of perfect fluid source. Using the special law of variation for Hubble’s parameter proposed by Berman (in Nuovo Cimento B 74:183, 1983), we have obtained a determinate solution which represents a dark energy cosmological model in the theory. We have also used the result that the scalar expansion is proportional to shear scalar of the space-time. It is observed that the EoS parameter, skewness parameter in the model turn out to be functions of cosmic time. Some physical and Kinematical properties of the model are also discussed.

Some Kaluza-Klein cosmological models in f(R,T) gravity theory

Algorithms are derived for constructing five dimensional Kaluza-Klein cosmological space-times in the presence of a perfect fluid source in the framework of f(R,T) gravity theory proposed by Harko et al. (Phys. Rev. D 84:024020, 2011). Starting from the solution of Reddy et al. (Int. J. Theor. Phys 51:3222-3227, 2012b) some classes of new solutions are generated which correspond to accelerating models of the Universe. The physical and kinematical behaviors of the models are studied.

Kaluza-Klein universe with cosmic strings and bulk viscosity in f(R,T) gravity

A five dimensional Kaluza-Klein cosmological model is considered in the frame work of f(R,T) gravity proposed by Harko et al. (Phys. Rev. D 84:024020, 2011) when the source for energy momentum tensor is a bulk viscous fluid containing one dimensional cosmic strings. A barotropic equation of state is assumed to get a determinate solution of the field equations. Also, the bulk viscous pressure is assumed to be proportional to the energy density. The physical behavior of the model is also discussed.

Kaluza-Klein interacting cosmic fluid cosmological model

In this paper, we have presented a power law scaling Kaluza-Klein cosmological model dominated by two interacting perfect fluid components during expansion. Barotropic equations of state for pressure and density are considered to get determinate solutions of the field equations. We have shown that the components are not conserved separately because of mutual interaction between the two fluids, and the energy densities are proportional to 1 t2

Static Extra Dimension and Acceleration of the Universe

We study a five dimensional FLRW type Kaluza-Klein cosmological model with static extra dimension. Accelerated expansion is found by assuming a linear relationship p b =mp a between pressures ‘p a ’ corresponding to the usual four dimension, and ‘p b ’ corresponding to the extra dimension. The field equations are obtained and solved, for different values of m, to analyse the cosmological consequences of the present model. It is found that m has the value between 2 and 3 to match with the present observational findings for the accelerated expansion of the universe.

Kaluza-Klein Type Cosmological Model of Early Universe with Variable Cosmological Term Λ: Kinematic Tests

Kaluza-Klein type cosmological model of universe are consider with variable Λ term in the presence of perfect fluid. We obtained exact solution of the field equations by using gamma law equation of state p=(γ−1)ρ, in which parameter γ depends on the scale factor R proposed by Carvalho (Int. J. Theor. Phys. 35:2019, 1996). A unified description of early universe is presented with the assumption Λ=βH2 in which inflationary phase is followed by radiation dominated phase. The various physical aspects of the cosmological models are also discussed. Analytic expressions for the look back time, proper distance, luminosity distance and angular diameter distance are derived and their meaning discussed in detail in the framework of higher dimensional space time.

Kaluza-Klein Cosmological Model in Self-Creation Cosmology

A five dimensional Kaluza-Klein Space-time is considered in the presence of a perfect fluid source in Barber’s (Gen. Relativ. Gravit. 14:117, 1982) second self-creation theory of gravitation. An exact cosmological model is presented using a relation between the metric potentials and an equation of state. Some physical and kinematical properties of the model are also discussed.

ROLE OF EXTRA DIMENSION IN ACCELERATED EXPANSION

A five-dimensional FRW-type Kaluza–Klein cosmological model is taken to study the role of extra dimension in the expansion of the universe. Relation between scale factors corresponding to conventional four dimensions and the extra dimension has been established. Field equations are solved in order to find out the effect of pressure corresponding to these scale factors. Conditions for accelerated expansion are derived.

String cloud and domain walls with quark matter in 5-D Kaluza–Klein cosmological model

In this study Kaluza–Klein Cosmological solutions are obtained for quark matter coupled to the string cloud and domain wall in the context of general relativity. For this purpose Einstein field equations are solved by using anisotropy feature of the universe in the five-dimensional Kaluza–Klein Cosmological model. Also, the features of obtained solutions are discussed.