📝 SummarXiv

Abstract

We explore the renormalization group-based extension of the $\Lambda$CDM model as a potential solution to the current cosmological tensions. In this approach, both the cosmological constant density and Newton's constant are allowed to vary with the energy scale, as a consequence of the remnant effects of massive quantum fields in the low-energy regime. The corresponding cosmological model is consistent with the principles of quantum field theory, based on the covariance of the vacuum effective action, and is characterized by an unique extra parameter $\nu$. Our analysis yields a best-fit value of $\nu = - (2.5 \pm 1.3)\times 10^{-4}$, placing the $\Lambda$CDM limit at the $2\sigma$ region of the $\nu$ posterior. This narrow range is consistent with data from CMB (Planck), BAO (DESI), and SN Ia (DES Y5). Our result also alleviates the $H_0$ tension and is consistent with the previously established constraints from large-scale structure. In this kind of models there is a link between cosmology and particle physics. Our results point to possibility of a new physics, characterized by a mass spectrum lying below the Planck scale but above the values typically associated with Grand Unified Theories (GUTs).