The Solution to the Fine-Tuning in Extended Quintessence Cosmologies
Carlo Baccigalupi
SISSA / ISAS
bacci@sissa.it
Additional authors: Sabino Matarrese, Francesca Perrotta
We address the fine-tuning problem in dark energy cosmology, focusing on the implications of the coupling between the quintessence scalar field and the Ricci scalar. We show that even if the equation of state today is close to-1, by virtue of the scalar-tensor coupling the quintessence trajectories still possess the attractive feature which allows to reach the present level of cosmic acceleration starting by a set of initial conditions which covers tens of orders of magnitude; this effect, entirely of gravitational origin, represents a new important consequence of the coupling between dark energy and Gravity. We illustrate this effect in typical Extended Quintessence scenarios.
