Physics – High Energy Physics – High Energy Physics - Theory
Scientific paper
2006-08-25
JCAP 0701:006,2007
Physics
High Energy Physics
High Energy Physics - Theory
18 pages, 4 figures, version to appear in JCAP
Scientific paper
10.1088/1475-7516/2007/01/006
The Gauss-Bonnet (GB) curvature invariant coupled to a scalar field $\phi$ can lead to an exit from a scaling matter-dominated epoch to a late-time accelerated expansion, which is attractive to alleviate the coincident problem of dark energy. We derive the condition for the existence of cosmological scaling solutions in the presence of the GB coupling for a general scalar-field Lagrangian density $p(\phi, X)$, where $X=-(1/2)(\nabla \phi)^2$ is a kinematic term of the scalar field. The GB coupling and the Lagrangian density are restricted to be in the form $f(\phi) \propto e^{\lambda \phi}$ and $p=Xg (Xe^{\lambda \phi})$, respectively, where $\lambda$ is a constant and $g$ is an arbitrary function. We also derive fixed points for such a scaling Lagrangian with a GB coupling $f(\phi) \propto e^{\mu \phi}$ and clarify the conditions under which the scaling matter era is followed by a de-Sitter solution which can appear in the presence of the GB coupling. Among scaling models proposed in the current literature, we find that the models which allow such a cosmological evolution are an ordinary scalar field with an exponential potential and a tachyon field with an inverse square potential, although the latter requires a coupling between dark energy and dark matter.
Sami M.
Tsujikawa Shinji
No associations
LandOfFree
String-inspired cosmology: Late time transition from scaling matter era to dark energy universe caused by a Gauss-Bonnet coupling 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 String-inspired cosmology: Late time transition from scaling matter era to dark energy universe caused by a Gauss-Bonnet coupling, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and String-inspired cosmology: Late time transition from scaling matter era to dark energy universe caused by a Gauss-Bonnet coupling will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-111477