This manuscript is devoted to the investigation of the Bianchi type I universe in the context of f(R, T) gravity. For this purpose, we explore the exact solutions of locally rotationally symmetric Bianchi type I spacetime. The modified field equations are solved by assuming an expansion scalar $$\theta $$
 proportional to the shear scalar $$\sigma $$
 , which gives $$A=B^n$$
 , where A,  B are the metric coefficients and n is an arbitrary constant. In particular, three solutions have been found and physical quantities are calculated in each case.

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Locally rotationally symmetric Bianchi type I cosmology in f(R, T) gravity

We study Bianchi type I cosmological model in the presence of magnetized anisotropic dark energy. The energy-momentum tensor consists of anisotropic fluid with anisotropic EoS p=ωρ and a uniform magnetic field of energy density ρB. We obtain exact solutions to the field equations using the condition that expansion is proportional to the shear scalar. The physical behavior of the model is discussed with and without magnetic field. We conclude that universe model as well as anisotropic fluid do not approach isotropy through the evolution of the universe.

Dynamics of Bianchi I universe with magnetized anisotropic Dark Energy

The present study deals with spatially homogeneous and totally anisotropic locally rotationally symmetric (LRS) Bianchi type I cosmological model with variable $G$ and $\Lambda$ in presence of imperfect fluid. To get the deterministic model of Universe, we assume that the expansion $(\theta)$ in the model is proportional to shear $(\sigma)$. This condition leads to $A=\ell B^{n}$, where $A$,\;$B$ are metric potential. The cosmological constant $\Lambda$ is found to be decreasing function of time and it approaches a small positive value at late time which is supported by recent Supernovae Ia (SN Ia) observations. Also it is evident that the distance modulus curve of derived model matches with observations perfectly.

Bulk Viscous LRS Biachi-I Universe with variable $G$ and decaying $\Lambda$

The present study deals with spatially homogeneous and totally anisotropic locally rotationally symmetric (LRS) Bianchi type I cosmological model with variable G and Λ in presence of imperfect fluid. To get the deterministic model of Universe, we assume that the expansion (θ) in the model is proportional to shear (σ). This condition leads to A=lBn, where A, B are metric potential. The cosmological constant Λ is found to be decreasing function of time and it approaches a small positive value at late time which is supported by recent Supernovae Ia (SN Ia) observations. Also it is evident that the distance modulus curve of derived model matches with observations perfectly.

Bulk viscous LRS Bianchi-I Universe with variable G and decaying Λ

In this paper, we investigate the behavior of equa- tion of state parameter and energy density for dark energy in the framework of f( T ) gravity. For this purpose, we use anisotropic LRS Bianchi type I universe model. The be- havior of accelerating universe is discussed for some well- known f( T ) models. It is found that the universe takes a transition between phantom and non-phantom phases for f( T ) models except exponential and logarithmic models. We conclude that our results are relativity analogous to the results of FRW universe.

Cosmological evolution for dark energy models in f(T) gravity

Bulk viscous L.R.S. Bianchi type V tilted stiff fluid cosmological model in general relativity

Bianchi Type I tilted cosmological model for barotropic perfect fluid distribution with heat conduction is investigated.To get the deterministic solution, we have assumed barotropic condition p = γ ∈ ,0 < γ < 1, p being isotropic pressure, ∈ the matter density and a supplementary condition between metric potentials A, B, C as A = (BC)n where n is the constant. To get the model in terms of cosmic time, we have also discussed some special cases. The physical aspects of the model are also discussed.

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Bianchi type I tilted cosmological model for barotropic perfect fluid distribution with heat conduction in general relativity

Tilted Bianchi type-V barotropic fluid cosmological models with heat conduction and variable bulk viscosity is investigated. To get the deterministic model of the universe, we have assumed two conditions: (i) A = (BC)n and (ii) ζθ = const where A, B, C are metric potentials, n is a constant, ζ the coefficient of bulk viscosity, θ the expansion in the model. The behavior of the model in presence and absence of bulk viscosity and singularities in the model are discussed. Some thermodynamic relations and physical aspects of the model related to the observation on the present day universe are also discussed.

Pramila Kumawat

Papers

Bulk viscous L.R.S. Bianchi type V tilted stiff fluid cosmological model in general relativity

Bianchi type I tilted cosmological model for barotropic perfect fluid distribution with heat conduction in general relativity

Tilted bianchi type-v barotropic fluid cosmological models with variable bulk viscosity in general relativity