Cosmology of the Planck era from a renormalization group for quantum gravity

By Alfio M. Bonanno, Martin Reuter. 2001

261 citations recorded by the source corpus.

Homogeneous and isotropic cosmologies of the Planck era before the classical Einstein equations become valid are studied taking quantum gravitational effects into account. The cosmological evolution equations are renormalization group improved by including the scale dependence of Newton's constant and of the cosmological constant as it is given by the flow equation of the effective average action for gravity. It is argued that the Planck regime can be treated reliably in this framework because gravity is found to become asymptotically free at short distances. The epoch immediately after the initial singularity of the Universe is described by an attractor solution of the improved equations which is a direct manifestation of an ultraviolet attractive renormalization group fixed point. It is shown that quantum gravity effects in the very early Universe might provide a resolution to the horizon and flatness problems of standard cosmology, and could generate a scale-free spectrum of primordial density fluctuations.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/4dc4bbaf03ff0f77764dbcb3608d1dd75f1a8497

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Citations in the corpus

Cosmology of the Lifshitz universe (2009, background): “For instance, some traits of the quantum dynamics are captured once the running of the couplings is taken into account and the equations of motion are RG improved, like in the Planckian cosmology of asymptotically safe gravity [10, 23, 26].”
Quantum field theory, gravity and cosmology in a fractal universe (2010, methodology): “This strategy is adopted, for instance, in the Planckian cosmology of asymptotically safe gravity thanks to its renormalization properties [60, 61, 62].”
The nonperturbative functional renormalization group and its applications (2020, methodology): “RG improvement has been used to derive quantum-gravity inspired models of inflation, see [1241–1251] and the early universe [1252, 1253].”
Hořava–Lifshitz dark energy (2009, methodology): “However, it would be interesting to use Renormalization Group methods to study the running of the quantities, leading to improved dynamics, similarly to the earlier works [48, 49].”
The Asymptotic Safety Scenario in Quantum Gravity (2006, unknown): “In the literature similar arguments have been used for the “renormalization group improvement” of cosmological [37, 38, 183, 28] and black hole spacetimes [36, 35, 40] on the basis of the effective average action (see also [189, 191, 190] for a discussion of different improvement schemes).”