%0 Journal Article
%T Conserved quantities in the perturbed Friedmann world model
%A J. Hwang
%J Physics
%D 1999
%I arXiv
%X The evolutions of linear structures in a spatially homogeneous and isotropic world model are characterized by some conserved quantities: the amplitude of gravitational wave is conserved in the super-horizon scale, the perturbed three-space curvature in the comoving gauge is conserved in the super-sound-horizon scale, and the angular momentum of rotational perturbation is generally conserved.
%U http://arxiv.org/abs/astro-ph/9909150v1