2011/01/31 by Mark Hindmarsh, Daniel F. Litim, Daniel Litim +1 · 3 citations
Physics and Astronomy · #Asymptotic safety in quantum gravity #Black Holes and Theoretical Physics #Classical mechanics #Cosmology #Cosmology and Gravitation Theories #Dark energy #Fixed point #Friedmann equations #Galaxies: Formation, Evolution, Phenomena #Gravitation #Inflation (cosmology) #Infrared fixed point #Mathematical physics #Metric expansion of space #Physics #Quantum #Quantum gravity #Quantum mechanics #Renormalization group #Scalar (mathematics) #Scalar field #Scale factor (cosmology) #Theoretical physics #Universe #astro-ph.CO #gr-qc #hep-th
paper · pdf · doi:10.1088/1475-7516/2011/07/019
published as JCAP 1107:019,2011 · 8 pages; v2: explanations and references added, accepted for publication in JCAP
arxiv created 2011/06/15 · openalex publication_date 2011/07/11 · arxiv updated 2011/07/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We study quantum modifications to cosmology in a Friedmann-Robertson-Walker universe with and without scalar fields by taking the renormalisation group running of gravitational and matter couplings into account. We exploit the Bianchi identity to relate the renormalisation group scale with scale factor and derive the improved cosmological evolution equations. We find two types of cosmological fixed points where the renormalisation group scale either freezes in, or continues to evolve with scale factor. We discuss the implications of each of these, and classify the different cosmological fixed points with and without gravity displaying an asymptotically safe renormalisation group fixed point. We state conditions of existence for an inflating ultraviolet cosmological fixed point for Einstein gravity coupled to a scalar field. We also discuss other fixed point solutions such as "scaling" solutions, or fixed points with equipartition between kinetic and potential energies.