1/R gravity and scalar-tensor gravity

@article{Chiba20031RGA,
  title={1/R gravity and scalar-tensor gravity},
  author={Takeshi Chiba},
  journal={Physics Letters B},
  year={2003},
  volume={575},
  pages={1-3}
}
  • T. Chiba
  • Published 18 July 2003
  • Physics
  • Physics Letters B
Abstract We point out that extended gravity theories, the Lagrangian of which is an arbitrary function of scalar curvature R , are equivalent to a class of the scalar-tensor theories of gravity. The corresponding gravity theory is ω =0 Brans–Dicke gravity with a potential for the Brans–Dicke scalar field, which is not compatible with solar system experiments if the field is very light: the case when such modifications become important recently. 
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References

SHOWING 1-10 OF 18 REFERENCES
Extended gravity theories and the Einstein--Hilbert action
I discuss the relation between arbitrarily high-order theories of gravity and scalar--tensor gravity at the level of the field equations and the action. I show that (2n+4)-order gravity isExpand
Inflation and the Conformal Structure of Higher Order Gravity Theories
Abstract We examine gravity theories derived from a gravitational lagrangian that is and analytic function ƒ(R) of the scalar curvature R in a space-time of arbitrary dimension D. We show that theyExpand
Reconstruction of a scalar-tensor theory of gravity in an accelerating universe
TLDR
The present acceleration of the Universe strongly indicated by recent observational data can be modeled in the scope of a scalar-tensor theory of gravity by determining the structure of this theory along with the present density of dustlike matter from two observable cosmological functions. Expand
Fourth-order gravity as general relativity plus matter
The fourth-order gravity theory with lagrangian R − 2Λ + αR2 is shown to be conformally equivalent to Einstein gravity with a massive scalar field. Some consequences for black holes and cosmology areExpand
Scalar-tensor gravity in an accelerating universe
We consider scalar-tensor theories of gravity in an accelerating universe. The equations for the background evolution and the perturbations are given in full generality for any parametrization of theExpand
Physical equivalence between nonlinear gravity theories and a general-relativistic self-gravitating scalar field.
TLDR
The global net of relationships between the nonlinear gravity theories, scalar-tensor theories, and general relativity is clarified, showing that in a sense these are ``canonically conjugated'' to each other. Expand
A New Type of Isotropic Cosmological Models without Singularity - Phys. Lett. B91, 99 (1980)
Abstract The Einstein equations with quantum one-loop contributions of conformally covariant matter fields are shown to admit a class of nonsingular isotropic homogeneous solutions that correspond toExpand
Quintessence, the gravitational constant, and gravity
Dynamical vacuum energy or quintessence, a slowly varying and spatially inhomogeneous component of the energy density with negative pressure, is currently consistent with the observational data. OneExpand
The Cauchy problem for the R+R2 theories of gravity without torsion
The exterior Cauchy problem is discussed for the fourth‐order theories of gravity derived from the Lagrangian densities L=(−g)1/2 (R+ (1/2)aR2+bRμν Rμν) −κLm. When b≠0, the Cauchy problem can beExpand
A comment on brane bending and ghosts in theories with infinite extra dimensions
Abstract Theories with infinite volume extra dimensions open exciting opportunities for particle physics. We argued recently that along with attractive features there are phenomenologicalExpand
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1
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