Astronomy and Astrophysics – Astrophysics – General Relativity and Quantum Cosmology
Scientific paper
2005-09-15
Phys.Rev.D72:103005,2005
Astronomy and Astrophysics
Astrophysics
General Relativity and Quantum Cosmology
26 pages and 5 figures. Published version
Scientific paper
10.1103/PhysRevD.72.103005
We study the cosmological and weak-field properties of theories of gravity derived by extending general relativity by means of a Lagrangian proportional to $R^{1+\delta}$. This scale-free extension reduces to general relativity when $\delta \to 0$. In order to constrain generalisations of general relativity of this power class we analyse the behaviour of the perfect-fluid Friedmann universes and isolate the physically relevant models of zero curvature. A stable matter-dominated period of evolution requires $\delta >0$ or $\delta <-1/4$. The stable attractors of the evolution are found. By considering the synthesis of light elements (helium-4, deuterium and lithium-7) we obtain the bound $-0.017<\delta <0.0012.$ We evaluate the effect on the power spectrum of clustering via the shift in the epoch of matter-radiation equality. The horizon size at matter--radiation equality will be shifted by $\sim 1%$ for a value of $\delta \sim 0.0005.$ We study the stable extensions of the Schwarzschild solution in these theories and calculate the timelike and null geodesics. No significant bounds arise from null geodesic effects but the perihelion precession observations lead to the strong bound $\delta =2.7\pm 4.5\times 10^{-19}$ assuming that Mercury follows a timelike geodesic. The combination of these observational constraints leads to the overall bound $0\leq \delta <7.2\times 10^{-19}$ on theories of this type.
Barrow John D.
Clifton Timothy
No associations
LandOfFree
The Power of General Relativity does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Power of General Relativity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Power of General Relativity will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-406920