Modified gravity with f(R)={radical}(R{sup 2}-R{sub 0}{sup 2})
- Department of Physics, Sharif University of Technology, P.O.Box 11365-9161, Tehran (Iran, Islamic Republic of)
In this work we propose a modified gravity with the action f(R)={radical}(R{sup 2}-R{sub 0}{sup 2}) instead of the Einstein-Hilbert action to describe the late time acceleration of the Universe. We obtain the equation of the modified gravity both in the metric and Palatini formalisms. An asymptotic solution of gravity equations corresponding to a constant Ricci scalar causes a late time acceleration of the Universe. We do a conformal transformation in the action of the modified gravity and obtain the equivalent minimally coupled scalar-tensor gravity. The equivalent Brans-Dicke gravity of this model is also studied. To examine this model with observation, the perihelion precession of the Mercury is compared with our prediction and we put an upper constraint of R{sub 0}<H{sub 0}{sup 2}. This range for R{sub 0} is also in agreement with the cosmological acceleration at the present time. Finally we show that this action has instability for the small perturbations of the metric in vacuum solution in which adding a quadratic term of Ricci scalar can stabilize it.
- OSTI ID:
- 21011089
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 75, Issue 4; Other Information: DOI: 10.1103/PhysRevD.75.044024; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
Similar Records
Linearized f(R) gravity: Gravitational radiation and Solar System tests
Hamiltonian formulation of Palatini f(R) theories a la Brans-Dicke theory