Extended quintessence with nonminimally coupled phantom scalar field
- Department of Theoretical Physics, Faculty of Philosophy, John Paul II Catholic University of Lublin, Al. Raclawickie 14, 20-950 Lublin (Poland)
We investigate evolutional paths of an extended quintessence with a nonminimally coupled phantom scalar field {psi} to the Ricci curvature. The dynamical system methods are used to investigate typical regimes of dynamics at the late time. We demonstrate that there are two generic types of evolutional scenarios which approach the attractor (a focus or a node type critical point) in the phase space: the quasioscillatory and monotonic trajectories approach the attractor which represents the Friedmann-Robertson-Walker model with the cosmological constant. We demonstrate that the dynamical system admits an invariant two-dimensional submanifold and discuss that which cosmological scenario is realized depends on the behavior of the system on the phase plane ({psi},{psi}{sup '}). We formulate simple conditions on the value of the coupling constant {xi} for which trajectories tend to the focus in the phase plane and hence damping oscillations around the mysterious value w=-1. We describe this condition in terms of slow-roll parameters calculated at the critical point. We discover that the generic trajectories in the focus-attractor scenario come from the unstable node. We also investigate the exact form of the parametrization of the equation of state parameter w(z) (directly determined from dynamics) which assumes a different form for both scenarios.
- OSTI ID:
- 21024018
- Journal Information:
- Physical Review. D, Particles Fields, Vol. 76, Issue 12; Other Information: DOI: 10.1103/PhysRevD.76.123510; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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