Cosmological Perturbations in Renormalization Group Derived Cosmologies

Abstract

A linear cosmological perturbation theory of an almost homogeneous and isotropic perfect fluid Universe with dynamically evolving Newton constant $G$ and cosmological constant $Λ$ is presented. A gauge-invariant formalism is developed by means of the covariant approach, and the acoustic propagation equations governing the evolution of the comoving fractional spatial gradients of the matter density, $G$, and $Λ$ are thus obtained. Explicit solutions are discussed in cosmologies where both $G$ and $Λ$ vary according to renormalization group equations in the vicinity of a fixed point.

22 pages, revtex, subeqn.sty, to appear on IJMPD