Bianchi type III models with anisotropic dark energy

• Published in: General relativity and gravitation Vol. 42; no. 4; pp. 763 - 775
• Main Authors: Akarsu, Ozgur, Kilinc, Can Battal
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.04.2010
• Subjects: Astronomy; Astrophysics and Cosmology; Classical and Quantum Gravitation; Differential Geometry; Mathematical and Computational Physics; Physics; Physics and Astronomy; Quantum Physics; Relativity Theory; Research Article; Theoretical; Isotropization; Bianchi type III; Dark energy; Anisotropic fluid
• ISSN: 0001-7701; 1572-9532
• DOI: 10.1007/s10714-009-0878-7

The general form of the anisotropy parameter of the expansion for Bianchi type-III metric is obtained in the presence of a single diagonal imperfect fluid with a dynamically anisotropic equation of state parameter and a dynamical energy density in general relativity. A special law is assumed for the anisotropy of the fluid which reduces the anisotropy parameter of the expansion to a simple form ( , where Δ is the anisotropy parameter, H is the mean Hubble parameter and V is the volume of the universe). The exact solutions of the Einstein field equations, under the assumption on the anisotropy of the fluid, are obtained for exponential and power-law volumetric expansions. The isotropy of the fluid, space and expansion are examined. It is observed that the universe can approach to isotropy monotonically even in the presence of an anisotropic fluid. The anisotropy of the fluid also isotropizes at later times for accelerating models and evolves into the well-known cosmological constant in the model for exponential volumetric expansion.