Instability of scalar perturbation in a phantomic cosmological scenario

Abstract

Scalar perturbations can grow during a phantomic cosmological phase as the big rip is approached, in spite of the high accelerated expansion regime, if the equation of state is such that $\frac{p}{\rho }=\alpha <-5/3$. It is shown that such result is independent of the spatial curvature. The perturbed equations are exactly solved for any value of the curvature parameter $k$ and of the equation of state parameter $\alpha$. Growing modes are found asymptotically under the condition $\alpha <-5/3$. Since the Hubble radius decreases in a phantom universe, such result indicates that a phantom scenario may not survive longtime due to gravitational instability.

Latex file, 6 pages

References in corpus (3)

• Wilkinson Microwave Anisotropy Probe (WMAP) Three Year Results: Implications for Cosmology
• Hidden past of dark energy cosmological models
• Scalar perturbations and the possible self-destruction of the phantom menace

Cited by in corpus (2)

• Classical Stability of Sudden and Big Rip Singularities
• Quasi-Rip: A New Type of Rip Model without Cosmic Doomsday