 |
|
|
|
|
 |
|
|
Gauss-Bonnet cosmologies: crossing the phantom divide and the transition from matter dominance to dark energy
|
|
|
|
|
|
| Organization: | University of Canterbury |
| Department: | Department of Physics and Astronomy |
| Department: | Theory Division |
|
|
|
|
|
|
| Journal of Cosmology and Astroparticle Physics |
|
|
|
|
|
|
Dark energy cosmologies with an equation of state parameter w less than -1 are often found to violate the null energy condition and show unstable behaviour. A solution to this problem may require the existence of a consistent effective theory that violates the null energy condition only momentarily and does not develop any instabilities or other pathological features for a late time cosmology. A model which incorporates a dynamical scalar field coupled to the quadratic Riemann invariant of the Gauss-Bonnet form is a viable proposal. Such an effective theory is shown to admit non-singular cosmological evolutions for a wide range of scalar-Gauss-Bonnet coupling. We discuss the conditions for which our model yields observationally supported spectra of scalar and tensor fluctuations, under cosmological perturbations. The model can provide a reasonable explanation for the transition from matter dominance to dark energy regime and the late time cosmic acceleration, offering an interesting testing ground for investigations of the cosmological modified gravity.
|
|
|
|
|
|
|
|
|
|
|
|
dark energy theory, cosmological perturbation theory, string theory and cosmology, inflation
|
|
For the newest resources, visit Wolfram Repositories and Archives »
