Can dark energy evolve to the phantom?
Abstract
Dark energy with the equation of state w(z) rapidly evolving from the dustlike (w≃0 at z∼1) to the phantomlike (1.2≲w≲1 at z≃0) has been recently proposed as the best fit for the supernovae Ia data. Assuming that a dark energy component with an arbitrary scalarfield Lagrangian p(φ,∇_{μ}φ) dominates in the flat Friedmann universe, we analyze the possibility of a dynamical transition from the states (φ,φ˙) with w≥1 to those with w<1 or vice versa. We have found that generally such transitions are physically implausible because they are either realized by a discrete set of trajectories in the phase space or are unstable with respect to the cosmological perturbations. This conclusion is confirmed by a comparison of the analytic results with numerical solutions obtained for simple models. Without the assumption of the dark energy domination, this result still holds for a certain class of dark energy Lagrangians, in particular, for Lagrangians quadratic in ∇_{μ}φ. The result is insensitive to topology of the Friedmann universe as well.
 Publication:

Physical Review D
 Pub Date:
 January 2005
 DOI:
 10.1103/PhysRevD.71.023515
 arXiv:
 arXiv:astroph/0407107
 Bibcode:
 2005PhRvD..71b3515V
 Keywords:

 95.35.+d;
 98.80.Cq;
 04.40.Nr;
 11.10.Lm;
 Dark matter;
 Particletheory and fieldtheory models of the early Universe;
 EinsteinMaxwell spacetimes spacetimes with fluids radiation or classical fields;
 Nonlinear or nonlocal theories and models;
 Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Theory
 EPrint:
 15 pages, 9 figures, corrected typos, exposition is improved