2007/12/31 by Pedro F. Machado, Frank Saueressig · 261 citations
Mathematics · Physics and Astronomy · #Black Holes and Theoretical Physics #Combinatorics #Conjecture #Cosmology and Gravitation Theories #Fixed point #Flow (mathematics) #Mathematical analysis #Mathematical physics #Mathematics #Noncommutative and Quantum Gravity Theories #Physics #Quantum #Quantum gravity #Quantum mechanics #Renormalization group #Statistics #Truncation (statistics) #hep-th
paper · pdf · doi:10.1103/physrevd.77.124045
published in Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields 77(12) (American Physical Society) · 55 pages, 7 figures, typos corrected, references added, version to appear in Phys. Rev. D
arxiv created 2008/04/29 · openalex publication_date 2008/06/26 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We use the functional renormalization group equation for quantum gravity to construct a nonperturbative flow equation for modified gravity theories of the form S=\ensuremath∫ddx√(g)f(R). Based on this equation we show that certain gravitational interaction monomials can be consistently decoupled from the renormalization group (RG) flow and reproduce recent results on the asymptotic safety conjecture. The nonperturbative RG flow of nonlocal extensions of the Einstein-Hilbert truncation including \ensuremath∫ddx√(g)ln(R) and \ensuremath∫ddx√(g)R^\ensuremath-n interactions is investigated in detail. The inclusion of such interactions resolves the infrared singularities plaguing the RG trajectories with positive cosmological constant in previous truncations. In particular, in some R^\ensuremath-n truncations all physical trajectories emanate from a non-Gaussian (UV) fixed point and are well-defined on all RG scales. The RG flow of the ln(R) truncation contains an infrared attractor which drives a positive cosmological constant to zero dynamically.