Higher-Dimensional Cosmological Models with Density-Parameter-Dependent Cosmological Constant

We discuss the evolution of the scale factor in a higher-dimensional cosmological model in which the cosmological constant is given by the scalar arisen by the contraction of the stress-energy tensor.     

Locally Rotationally Symmetric Bianchi Type-Ⅰ Model with Time Varying Λ Term

We investigate the locally rotationally symmetric （LRS） Bianchi type-Ⅰ cosmological model for stiff matter and a vacuum solution with a cosmological term proportional to R^-m （R is the scale factor and m is a positive constant）. The cosmological term decreases with time. We obtain that for both the cases the present universe is accelerating with a large fraction of cosmological density in the form of a cosmological term.     

Dark Energy Models and Cosmic Acceleration with Anisotropic Universe in f（T） Gravity

This paper is devoted to studing the accelerated expansion of the universe in context of f（T） theory of gravity. For this purpose, we construct different f（T） models and investigate their cosmological behavior through equation of state parameter by using holographic, new agegraphic and their power-law entropy corrected dark energy models. We discuss the graphical behavior of this parameter versus redshif~ for particular values of constant parameters in Bianchi type I universe model. It is shown that the universe lies in different forms of dark energy, namely quintessence, phantom, and quintom corresponding to the chosen scale factors, which depend upon the constant parameters of the models.     

Bianchi Type III Bulk Viscous Barotropic Fluid Cosmological Models with Variable G and Λ

Bianchi type-Ⅲ bulk viscous barotropic fluid cosmological model with variables G and A is investigated. To obtain the realistic model, we assume the conditions between the metric potentials A, B, C as A/A = B/B = m1/t^N and C/C = m2/t^n, P = p - 3ηH, η =ηop^s, p=γρ, 0 ≤ γ ≤ 1, where p is isotropic pressure,η the coefficient of bulk viscosity, η0 and S the constants, H the Hubble constant, m1 = 2m2 where m1 〉 0, m2 〉 O. The solutions obtained lead to inflationary phase and the results obtained match with the observations. The case n = 1 for S = 1 is also discussed, relating the results with the observations.