Grand Rip and Grand Bang/Crunch cosmological singularities

摘要

The present accelerated expansion of the universe has enriched the list ofpossible scenarios for its fate, singular or not. In this paper a unifyingframework for analyzing such behaviors is proposed, based on generalized powerand asymptotic expansions of the barotropic index $w$, or equivalently of thedeceleration parameter $q$, in terms of the time coordinate. Besides well knownsingular and non-singular future behaviors, other types of strong singularitiesappear around the phantom divide in flat models, with features similar to thoseof big rip or big bang/crunch, which we have dubbed grand rip and grandbang/crunch respectively, since energy density and pressure diverge faster than$t^{-2}$ in coordinate time. In addition to this, the scale factor does notadmit convergent generalized power series around these singularities with afinite number of terms with negative powers.