2005/11/30 by Ignacio Martín-Navarro, Ignacio Navarro, Karel Van Acoleyen · 1 citation
Physics and Astronomy · #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Relativity and Gravitational Theory #astro-ph #gr-qc #hep-th
paper · pdf · doi:10.1088/1475-7516/2006/03/008
published as JCAP 0603 (2006) 008 · 27 pages, 1 figure, v2. references added, improved discussion
arxiv created 2005/12/09 · openalex publication_date 2006/03/10 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/30
In this paper we study long distance modifications of gravity obtained by considering actions that are singular in the limit of vanishing curvature. In particular, we showed in a previous publication that models that include inverse powers of curvature invariants that diverge for in the Schwarzschild geometry recover an acceptable weak field limit at short distances from sources. We study then the linearization of generic actions of the form where P = R μν R μν and Q = R μνλσ R μνλσ . We show that for the case in which F [ R , P , Q ] = F [ R , Q − 4 P ], the theory is ghost free. Assuming this is the case, in the models that can explain the acceleration of the Universe without recourse to Dark Energy there is still an extra scalar field in the spectrum besides the massless spin two graviton. The mass of this extra excitation is of the order of the Hubble scale in vacuum. We nevertheless recover Einstein gravity at short distances because the mass of this scalar field depends on the background in such a way that it effectively decouples when one gets close to any source. Remarkably, for the values of the parameters necessary to explain the cosmic acceleration the induced modifications of gravity are suppressed at the Solar System level but can be important for systems like a galaxy.