2019/08/31 by Nicolas R. Bertini, Wiliam S. Hipólito-Ricaldi, Wiliam S. Hipolito-Ricaldi +2
Physics and Astronomy · #Astrophysics #Black Holes and Theoretical Physics #Cosmology #Cosmology and Gravitation Theories #Dark energy #Dimensionless quantity #Effective action #Galaxies: Formation, Evolution, Phenomena #Galaxy #General relativity #Lambda #Mathematical physics #Physics #Quantum gravity #Quantum mechanics #Redshift #Renormalization group #Sigma #Theoretical physics #astro-ph.CO #f(R) gravity #gr-qc
paper · pdf · doi:10.1140/epjc/s10052-020-8041-4
published as Eur. Phys. J. C 80, 479 (2020) · v3: 13 pages, 1 figure. Added $fσ_8$ analysis and text improvements. Version to appear in EPJC
openalex publication_date 2020/05/01 · arxiv created 2020/05/12 · arxiv updated 2020/06/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Abstract General relativity (GR) extensions based on renormalization group (RG) flows may lead to scale-dependent couplings with nontrivial effects at large distance scales. Here we develop further the approach in which RG effects at large distance scales are fully encoded in an effective action and we apply it to cosmology. In order to evaluate the cosmological consequences, our main assumption is the use of a RG scale such that the (infrared) RG effects only appear at perturbative order (not at the background level). The emphasis here is on analytical results and qualitative understanding of the implied cosmology. We employ commonly used parametrizations for describing modified gravity in cosmology (as the slip parameter). From them, we describe the dynamics of the first order perturbations and estimate bounds on the single dimensionless parameter ( ν <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ν</mml:mi></mml:math> ) introduced by this framework. Possible impacts on dark matter and dark energy are discussed. It is also shown here that the ν <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ν</mml:mi></mml:math> parameter effects to fσ 8 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>f</mml:mi><mml:msub><mml:mi>σ</mml:mi><mml:mn>8</mml:mn></mml:msub></mml:mrow></mml:math> are stronger at low redshifts ( zlt;1.5 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>z</mml:mi><mml:mo><</mml:mo><mml:mn>1.5</mml:mn></mml:mrow></mml:math> ), while different values for ν <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>ν</mml:mi></mml:math> do not appreciably change fσ 8 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>f</mml:mi><mml:msub><mml:mi>σ</mml:mi><mml:mn>8</mml:mn></mml:msub></mml:mrow></mml:math> at higher redshifts, thus opening a window to alleviate an issue that is currently faced by Λ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>Λ</mml:mi></mml:math> CDM.