Theory of cosmological perturbations in an anisotropic universe
Theory of cosmological perturbations in an anisotropic universe
This paper describes the theory of cosmological perturbations around a homogeneous and anisotropic universe of the Bianchi I type. Starting from a general parametrization of the perturbed spacetime à la Bardeen, a complete set of gauge invariant variables is constructed. Three physical degrees of freedom are identified and it is …