The Accelerated expansion of the Universe as a crossover phenomenon

Abstract

We show that the accelerated expansion of the Universe can be viewed as a crossover phenomenon where the Newton constant and the Cosmological constant are actually scaling operators, dynamically evolving in the attraction basin of a non-Gaussian infrared fixed point, whose existence has been recently discussed. By linearization of the renormalized flow it is possible to evaluate the critical exponents, and it turns out that the approach to the fixed point is ruled by a marginal and a relevant direction. A smooth transition between the standard Friedmann--Lemaitre--Robertson--Walker (FLRW) cosmology and the observed accelerated expansion is then obtained, so that ${\Omega }_M\approx {\Omega }_{\Lambda }$ at late times.

12 pages, latex, use bibtex. In the final version, the presentation has been improved, and new references have been added

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• Bare Action and Regularized Functional Integral of Asymptotically Safe Quantum Gravity
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• The role of Background Independence for Asymptotic Safety in Quantum Einstein Gravity
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• One-loop f(R) Gravitational Modified Models
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• On the Possibility of Quantum Gravity Effects at Astrophysical Scales
• A matter-dominated cosmological model with variable $G$ and $\Lambda$. Confrontation of theoretical predictions with observational data
• Scale Dependent Metric and Minimal Length in QEG
• Phenomenological footprints of Lambda varying gravity theories inspired from quantum gravity models in the multi-messenger era
• Renormalization group approaches to Quantum Gravity and Tensions in Modern Cosmology
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