Coupled dark energy: towards a general description of the dynamics

By Burin Gumjudpai, T. Naskar, M. Sami, S. Tsujikawa. 2005

232 citations recorded by the source corpus.

In dark energy models of scalar-field coupled to a barotropic perfect fluid, the existence of cosmological scaling solutions restricts the Lagrangian of the field φ to p = Xg(Xeλφ), where , λ is a constant and g is an arbitrary function. We derive general evolution equations in an autonomous form for this Lagrangian and investigate the stability of fixed points for several different dark energy models: (i) ordinary (phantom) field, (ii) dilatonic ghost condensate, and (iii) (phantom) tachyon. We find the existence of scalar-field dominant fixed points (Ωφ = 1) with an accelerated expansion in all models irrespective of the presence of the coupling Q between dark energy and dark matter. These fixed points are always classically stable for a phantom field, implying that the universe is eventually dominated by the energy density of a scalar field if a phantom is responsible for dark energy. When the equation of state wφ for the field φ is larger than −1, we find that scaling solutions are stable if the scalar-field dominant solution is unstable, and vice versa. Therefore in this case the final attractor is either a scaling solution with constant Ωφ satisfying 0 < Ωφ < 1 or a scalar-field dominant solution with Ωφ = 1.

Subfields: Astronomy and Astrophysics, Finance, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/351e325284e941e3770da92964fec3029af79e79

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Finance

Francisco S. N. Lobo

In Nuclear and High Energy Physics

Citations in the corpus

Stability of phantom wormholes (2005, background): “However, recent fits to supernovae, CMB and weak gravitational lensing data indicate that an evolving equation of state ω crossing the phantom divide−1, is mildly favored, and several models have been proposed in the literature [6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16].”