Cosmological and Solar-System Tests of fR Modified Gravity - Astrophysics > Cosmology and Nongalactic AstrophysicsReport as inadecuate




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Abstract: We investigate the cosmological and the local tests of the fR theory ofmodified gravity via the observations of 1 the cosmic expansion and 2 thecosmic structures and via 3 the solar-system experiments. To fit the possiblecosmic expansion histories under consideration, for each of them we reconstructfR, known as -designer fR-. We then test the designer fR via thecosmic-structure constraints on the metric perturbation ratio Psi-Phi and theeffective gravitational coupling G eff and via the solar-system constraints onthe Brans-Dicke theory with the chameleon mechanism. We find that among thedesigner fR models specified by the CPL effective equation of state w eff,only the model closely mimicking general relativity with a cosmologicalconstant LambdaCDM can survive all the tests. Accordingly, these tests ruleout the frequently studied -w eff = -1- designer fR models which are distinctin cosmic structures from LambdaCDM. When considering only the cosmologicaltests, we find that the surviving designer fR models, although exist for avariety of w eff, entail fine-tuning.



Author: Wei-Ting Lin, Je-An Gu, Pisin Chen

Source: https://arxiv.org/







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