Metric-Palatini gravity unifying local constraints and late-time cosmic acceleration

By Tiberiu Harko, Tomi Koivisto, Francisco S. N. Lobo, G. Olmo. 2011

144 citations recorded by the source corpus.

We present a novel approach to modified theories of gravity which consists of adding to the Einstein- Hilbert Lagrangian an fðRÞ term constructed ala Palatini. Using the respective dynamically equivalent scalar-tensor representation, we show that the theory can pass the Solar System observational constraints even if the scalar field is very light. This implies the existence of a long-range scalar field, which is able to modify the cosmological and galactic dynamics but leaves the Solar System unaffected. We also verify the absence of instabilities in perturbations and provide explicit models which are consistent with local tests and lead to the late-time cosmic acceleration.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/049c42a7a70e8bb3eafbe20373c6e14dd655ab13

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Citations in the corpus

Effective field theory of dark energy: A review (2019, methodology): “• Hybrid-metric Palatini f(R̂) gravity [253]: the action is constructed by adding a Palatini correction f(R̂) to the usual Hilbert-Einstein term as”
Cosmology and Fundamental Physics with the Euclid Satellite (2012, methodology): “Here we confine ourselves to the metric case only; details of a viable model in unifying the metric and Palatini formalism can be found in [571].”
Generalized Curvature-Matter Couplings in Modified Gravity (2014, methodology): “atisﬁes the conditions U U= 1 and Ur U = 0, respectively. Then, with the use of Eq. (141), we obtain for the variation of the energy-momentum of a perfect ﬂuid the expression = 2T + pg : (143) Galaxies 2014, xx 31 The choice L m = ˆleads to a different form for , = 2T + ˆg . With this form of the”
Hybrid Metric-Palatini Gravity (2015, methodology): “Comparing again with the results obtained in [28] for the weak-field limit, we find that λ0 = 2GM/c.”
Stellar structure models in modified theories of gravity: Lessons and challenges (2019, background): “the matter sources/boundaryconditions or establish the domain of validity of the approximationsconsidered. 3.1.4. Other metric-aﬃne models A hybridversion of f(R) theories was proposedby Harko et al. [446] in the form S = 1 2κ2 Z d4x √ −g[R+ f(R)] +S m(gµν,ψ m) (189) whereR is the usual curvaturecon”