English

General solutions for flat Friedmann universe filled by perfect fluid and scalar field with exponential potential

General Relativity and Quantum Cosmology 2007-05-23 v1

Abstract

We study integrability by quadrature of a spatially flat Friedmann model containing both a minimally coupled scalar field ϕ\phi with an exponential potential V(ϕ)exp[6σκϕ]V(\phi)\sim\exp[-\sqrt{6}\sigma\kappa\phi], κ=8πGN\kappa=\sqrt{8\pi G_N}, of arbitrary sign and a perfect fluid with barotropic equation of state p=(1h)ρp=(1-h)\rho. From the mathematical view point the model is pseudo-Euclidean Toda-like system with 2 degrees of freedom. We apply the methods developed in our previous papers, based on the Minkowsky-like geometry for 2 characteristic vectors depending on the parameters σ\sigma and hh. In general case the problem is reduced to integrability of a second order ordinary differential equation known as the generalized Emden-Fowler equation, which was investigated by discrete-group methods. We present 4 classes of general solutions for the parameters obeying the following relations: {\bf A}. σ\sigma is arbitrary, h=0h=0; {\bf B}. σ=1h/2\sigma=1-h/2, 0<h<20<h<2; {\bf C1}. σ=1h/4\sigma=1-h/4, 0<h20<h\leq 2; {\bf C2}. σ=1h\sigma=|1-h|, 0<h20<h\leq 2, h1,4/3h\neq 1,4/3. We discuss the properties of the exact solutions near the initial singularity and at the final stage of evolution.

Keywords

Cite

@article{arxiv.gr-qc/0212107,
  title  = {General solutions for flat Friedmann universe filled by perfect fluid and scalar field with exponential potential},
  author = {H. Dehnen and V. R. Gavrilov and V. N. Melnikov},
  journal= {arXiv preprint arXiv:gr-qc/0212107},
  year   = {2007}
}

Comments

13 pages, Latex, 1 figure, submit. to Class. Quantum Grav