A metric-affine version of quadratic DHOST theories is derived and reduced to a one-function family that satisfies degeneracy conditions and light-speed gravitational wave propagation.
Metric-Palatini gravity unifying local constraints and late-time cosmic acceleration
4 Pith papers cite this work. Polarity classification is still indexing.
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abstract
We present a novel approach to modified theories of gravity that consists of adding to the Einstein-Hilbert Lagrangian an f(R) term constructed a la 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.
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gr-qc 4representative citing papers
Generalized hybrid metric-Palatini gravity propagates a massless spin-2 mode and two massive scalars in the weak field; stability requires algebraic conditions on f derivatives at flat space, and planetary data constrain the scalar masses in a hierarchical regime.
A unified post-Newtonian analysis shows that metric vs Palatini scalar-tensor gravity can yield different γ, β and Yukawa suppression, with Palatini f(R̂) recovering GR’s exterior PN limit for point sources.
Modified gravity theories supply viable mathematical frameworks for inflation, bounces, and dark energy eras that match observational data.
citing papers explorer
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Degenerate higher-order scalar-tensor theories in metric-affine gravity
A metric-affine version of quadratic DHOST theories is derived and reduced to a one-function family that satisfies degeneracy conditions and light-speed gravitational wave propagation.
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Another Look at the Weak-Field Limit of Generalized Hybrid Metric-Palatini Gravity
Generalized hybrid metric-Palatini gravity propagates a massless spin-2 mode and two massive scalars in the weak field; stability requires algebraic conditions on f derivatives at flat space, and planetary data constrain the scalar masses in a hierarchical regime.
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Post-Newtonian Constraints on Scalar-Tensor Gravity
A unified post-Newtonian analysis shows that metric vs Palatini scalar-tensor gravity can yield different γ, β and Yukawa suppression, with Palatini f(R̂) recovering GR’s exterior PN limit for point sources.
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Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution
Modified gravity theories supply viable mathematical frameworks for inflation, bounces, and dark energy eras that match observational data.