Coupled dark energy: Towards a general description of the dynamics
| dc.creator | Gumjudpai, Burin | |
| dc.creator | Naskar, Tapan | |
| dc.creator | Sami, M. | |
| dc.creator | Tsujikawa, Shinji | |
| dc.date | 2005-02-21 | |
| dc.date | 2005-06-02 | |
| dc.date.accessioned | 2026-07-07T12:46:21Z | |
| dc.date.available | 2026-07-07T12:46:21Z | |
| dc.description | 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 $\vp$ to $p=X g(Xe^{λ\vp})$, where $X=-g^{μν} \partial_μ\vp \partial_ν\vp /2$, $λ$ 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 ($Ω_\vp=1$) 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 phantom is responsible for dark energy. When the equation of state $w_\vp$ for the field $\vp$ 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 $Ω_\vp$ satisfying $0<Ω_\vp<1$ or a scalar-field dominant solution with $Ω_\vp=1$. | |
| dc.description | 21 pages, 5 figures; minor clarifications added, typos corrected and references updated; final version to appear in JCAP | |
| dc.identifier | https://arxiv.org/abs/hep-th/0502191 | |
| dc.identifier | http://arxiv.org/abs/hep-th/0502191 | |
| dc.identifier | JCAP 0506:007,2005 | |
| dc.identifier | doi:10.1088/1475-7516/2005/06/007 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/221353 | |
| dc.subject | High Energy Physics - Theory | |
| dc.subject | Astrophysics | |
| dc.subject | General Relativity and Quantum Cosmology | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.title | Coupled dark energy: Towards a general description of the dynamics | |
| dc.type | text |