Speaker
Description
Summary
As confirmed by a host of data from recent observations, the universe is presently undergoing an accelerated phase of expansion. The reason behind this acceleration, till date, is not known. However, an exotic form of energy dubbed as dark energy is attributed for this phenomena. In the present work, we keep an eye on this late time acceleration phenomena due to dark energy and constructed some cosmological models considering an anisotropic Bianchi V universe. The perfect fluid of the universe is considered to be different along different spatial direction of expansion. At late times, the deceleration parameter is considered to be negative and is slowly time varying or practically a constant. A negative value of the deceleration parameter simulates an accelerating universe. Alternately, this constant deceleration parameter leads to two different law for the volumetric expansion namely power law of expansion and exponential law of expansion. The skewness parameter or pressure anisotropies are calculated from the constructed models. In both the models, we found that the skewness parameters along with the equation of state parameter become time dependent. The pressure anisotropy can not be removed altogether even at late times and for a much older universe, there remains a residual pressure anisotropy. Eventhough, the skewness parameters are time dependent in both the models, an interesting result is found in the case of power law. For a particular choice of the exponent $n=\frac{2}{m+1}$, the skewness parameters along with the equation of state parameter comes out to be time independent implying a constant barotropic anisotropic fluid through the cosmic evolution.
