Bianchi type III models with anisotropic dark energy

Akarsu O., Kilinc C. B.

GENERAL RELATIVITY AND GRAVITATION, vol.42, no.4, pp.763-775, 2010 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 42 Issue: 4
  • Publication Date: 2010
  • Doi Number: 10.1007/s10714-009-0878-7
  • Journal Name: GENERAL RELATIVITY AND GRAVITATION
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.763-775
  • Keywords: Bianchi type III, Anisotropic fluid, Dark energy, Isotropization, CONSTANT DECELERATION PARAMETER, COSMOLOGICAL MODELS, INFLATIONARY UNIVERSE, VACUUM, FIELD, EXPANSION, FLATNESS, ISOTROPY, HORIZON, MAPS
  • Istanbul Technical University Affiliated: No

Abstract

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 (Delta proportional to H-2V-2, where Delta 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.