Evolution of cosmological perturbations in an RG-driven inflationary scenario

Abstract

A gauge-invariant, linear cosmological perturbation theory of an almost homogeneous and isotropic universe with dynamically evolving Newton constant G and cosmological constant $Λ$ is presented. The 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, featuring an accelerated expansion, where both G and $Λ$ vary according to renormalization group equations in the vicinity of an ultraviolet fixed point. Finally, a similar analysis is carried out in the late universe regime described by the part of the renormalization group trajectory close to the gaussian fixed point.

18 pages; improved discussion and references added; fitted to match published version