The present accelerated expansion of the Universe has enriched the list of possible scenarios for its fate, singular or not. In this paper a unifying framework for analyzing such behaviors is proposed, based on generalized power and asymptotic expansions of the barotropic index w, or equivalently of the deceleration parameter q, in terms of the time coordinate. Besides well-known singular and nonsingular future behaviors, other types of strong singularities appear around the phantom divide in flat models, with features similar to those of big rip or big bang/crunch, which we have dubbed "grand rip" and "grand bang/crunch," respectively, since energy density and pressure diverge faster than t-2 in coordinate time. In addition to this, the scale factor does not admit convergent generalized power series around these singularities with a finite number of terms with negative powers.
Physical Review D
- Pub Date:
- September 2014
- Singularities and cosmic censorship;
- Mathematical and relativistic aspects of cosmology;
- General Relativity and Quantum Cosmology
- 19 pages, 2 figures. Typos amended