Evolution of cosmological perturbations in a renormalization-group-driven inflationary scenario

A gauge-invariant, linear cosmological perturbation theory of an almost homogeneous and isotropic universe with dynamically evolving Newton constant G and cosmological constant Lambda is presented. The equations governing the evolution of the comoving fractional spatial gradients of the matter density, G and Lambda, are thus obtained. Explicit solutions are discussed in cosmologies, featuring an accelerated expansion, where both G and Lambda 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.