We study the coincidence problem of late cosmic acceleration by assuming that the present ratio between dark matter and dark energy is a slowly varying function of the scale factor. As the dark energy component we consider two different candidates, first a quintessence scalar field, and then a tachyon field. In either case analytical solutions for the scale factor, the field, and the potential are derived. Both models show a good fit to the recent magnitude-redshift supernovae data. However, the likelihood contours disfavor the tachyon field model as it seems to prefer a excessively high value for the matter component.
|Número de artículo||123529|
|Publicación||Physical Review D - Particles, Fields, Gravitation and Cosmology|
|Estado||Publicada - 15 jun 2005|
|Publicado de forma externa||Sí|