You are not logged in to this journal. Log in    |   Subscription Information

Phys. Rev. D 75, 023518 (2007) [20 pages]

Gauss-Bonnet quintessence: Background evolution, large scale structure, and cosmological constraints

Tomi Koivisto1,2 and David F. Mota3,4,5
1Helsinki Institute of Physics, FIN-00014 Helsinki, Finland
2Department of Physical Sciences, University of Helsinki, FIN-00014 Helsinki, Finland
3Institute for Theoretical Physics, University of Heidelberg, 69120 Heidelberg, Germany
4Institute of Theoretical Astrophysics, University of Oslo, Box 1029, 0315 Oslo, Norway
5Perimeter Institute, Waterloo, Ontario N2L 2Y5, Canada

Received 25 September 2006; published 19 January 2007

We investigate a string-inspired dark energy scenario featuring a scalar field with a coupling to the Gauss-Bonnet invariant. We discuss extensively the cosmological and astrophysical implications of the coupled scalar field. Such coupling can trigger the onset of late dark energy domination after a scaling matter era. The universe may then cross the phantom divide and perhaps also exit from the acceleration. The evolution of fluctuations in the scalar field and their impact on the clustering of matter are studied in detail and model independently. The small-scale limit is derived for the perturbations and their stability is addressed. The general equations for scalar perturbations are also presented and solved numerically, confirming that the Gauss-Bonnet coupling can be compatible with the observed spectrum of cosmic microwave background radiation as well as the matter power spectrum inferred from large-scale surveys. Data from the solar system, supernovae Ia, cosmic microwave background radiation, large-scale structure, and big bang nucleosynthesis are used to constrain the parameters of the model. The geometric constraints from background expansion favor exponential potentials with a shallow slope, which is in tension with the nucleosynthesis bound on early quintessence. Also, high values for the present matter density are required. Including the baryon oscillation scale, one could rule out the model at about 99% confidence level. A discussion of how to overcome such possible problems in more elaborate models is included, together with considerations of the validity of these constraints in the present context. Interestingly, one also finds that a good Newtonian limit may require fixing the coupling.

©2007 The American Physical Society

URL: http://link.aps.org/doi/10.1103/PhysRevD.75.023518
DOI: 10.1103/PhysRevD.75.023518
PACS: 98.80.Cq; 95.36.+x; 98.80.Jk
  • 98.80.Cq
    Particle-theory and field-theory models of the early Universe (including cosmic pancakes, cosmic strings, chaotic phenomena, inflationary universe, etc.)
  • 95.36.+x
    Dark energy
  • 98.80.Jk
    Mathematical and relativistic aspects of cosmology
  • YEAR: 2007
KEYWORDS: cosmology, dark energy, clusters of galaxies, radiofrequency cosmic radiation, nucleosynthesis, solar system, supernovae

REFERENCES (93)

For access to fully linked references, you need to log in. For access to fully linked references, you need to Log in.

CITING ARTICLES

For access to citing articles, you need to log in.
For access to citing articles, you need to Log in.



A new free weekly publication from APS

Physics - A new free weekly publication from APS
Please visit physics.aps.org
 
Article Tools