WMAP constraints on scalar-tensor cosmology and the variation of the gravitational constant
Abstract
We present observational constraints on a scalar-tensor gravity theory by χ2 test for the CMB anisotropy spectrum. We compare the WMAP temperature power spectrum with the harmonic attractor model, in which the scalar field has its harmonic effective potential with a curvature β in the Einstein conformal frame and the theory relaxes toward Einstein gravity with time. We find that the present value of the scalar coupling, i.e., the present level of deviation from Einstein gravity (α20), is bounded to be smaller than 5×10-4-7β (2σ), and 10-2-7β (4σ) for 0<β<0.45. This constraint is much stronger than the bound from the solar system experiments for large β models, i.e., β>0.2 and 0.3 in 2σ and 4σ limits, respectively. Furthermore, within the framework of this model, the variation of the gravitational constant at the recombination epoch is constrained as |G(z=zrec)-G0|/G0<0.05(2σ), and 0.23(4σ).
- Publication:
-
Physical Review D
- Pub Date:
- April 2004
- DOI:
- 10.1103/PhysRevD.69.083512
- arXiv:
- arXiv:astro-ph/0311274
- Bibcode:
- 2004PhRvD..69h3512N
- Keywords:
-
- 98.80.Es;
- 04.80.Cc;
- 98.65.Dx;
- Observational cosmology;
- Experimental tests of gravitational theories;
- Superclusters;
- large-scale structure of the Universe;
- Astrophysics;
- General Relativity and Quantum Cosmology;
- High Energy Physics - Phenomenology
- E-Print:
- 7 pages