Perturbations of an anisotropic spacetime: Ideal fluid

Publisher Website
Google Scholar
Abstract
In a previous paper we presented a general formulation that can treat the evolution of perturbations based on a Bianchi type-I background model universe. In this paper we apply the formulation to an ideal fluid system. The background model shows a smooth transition from the shear-dominated anisotropic stage to the ideal-fluid-dominated isotropic stage. In the shear-dominated stage the background anisotropy causes the couplings of the density perturbation with the gravitational wave and the rotation. The asymptotic solutions in the shear-dominated stage are derived. We investigate the solutions in the comoving gauge and the uniform-curvature gauge. Equations are presented using dimensionless variables; thus they are suitable for numerical investigation.