Phase-space analysis of torsion-coupled dilatonic ghost condensate

Abstract

We studied the cosmological dynamics of a dilatonic ghost condensate field as a source of dark energy, which is non-minimally coupled to gravity through torsion. We performed a detailed phase-space analysis by finding all the critical points and their stability conditions. Also, we compared our results with the latest $H(z)$ and Supernovae Ia observational data. In particular, we found the conditions for the existence of scaling regimes during the dark matter era. Furthermore, we obtained the conditions for a successful exit from the scaling regime, such that, at late times, the universe tends towards an attractor point describing the dark energy-dominated era. These intriguing features can allow us to alleviate the energy scale problem of dark energy since, during a scaling regime, the field energy density is not necessarily negligible at early times.