English

Thawing models in the presence of a generalized Chaplygin gas

Cosmology and Nongalactic Astrophysics 2013-10-31 v3 General Relativity and Quantum Cosmology

Abstract

In this paper we consider a cosmological model whose main components are a scalar field and a generalized Chaplygin gas. We obtain an exact solution for a flat arbitrary potential. This solution have the right dust limit when the Chaplygin parameter A0A\rightarrow 0. We use the dynamical systems approach in order to describe the cosmological evolution of the mixture for an exponential self-interacting scalar field potential. We study the scalar field with an arbitrary self-interacting potential using the "Method of ff-devisers." Our results are illustrated for the special case of a coshlike potential. We find that usual scalar-field-dominated and scaling solutions cannot be late-time attractors in the presence of the Chaplygin gas (with α>0\alpha>0). We recover the standard results at the dust limit (A0A\rightarrow 0). In particular, for the exponential potential, the late-time attractor is a pure generalized Chaplygin solution mimicking an effective cosmological constant. In the case of arbitrary potentials, the late-time attractors are de Sitter solutions in the form of a cosmological constant, a pure generalized Chaplygin solution or a continuum of solutions, when the scalar field and the Chaplygin gas densities are of the same orders of magnitude. The different situations depend on the parameter choices.

Keywords

Cite

@article{arxiv.1303.5779,
  title  = {Thawing models in the presence of a generalized Chaplygin gas},
  author = {Sergio del Campo and Carlos R. Fadragas and Ramon Herrera and Carlos Leiva and Genly Leon and Joel Saavedra},
  journal= {arXiv preprint arXiv:1303.5779},
  year   = {2013}
}

Comments

revtex4, 17 pages, 18 figures, discussion about fixed points 'at infinity' added, text slightly modified to match with the published version