Asymptotic properties of a supposedly regular (Dirac-Born-Infeld) modification of general relativity
Keywords: gravity, physics of the early universe, modified gravity, alternatives to inflation
Abstract
We apply the dynamical systems tools to study the asymptotic properties of a cosmological model based on a non-linear modification of General Relativity in which the standard Einstein-Hilbert action is replaced by one of Dirac-Born-Infeld type. It is shown that the dynamics of this model is extremely rich: there are found equilibrium points in the phase space that can be associated with matter-dominated, matter-curvature scaling, de Sitter, and even phantom-like solutions. Depending on the value of the overall parameters the dynamics in phase space can show multi-attractor structure into the future (multiple future attractors may co-exist). This is a consequence of bifurcations in control parameter space, showing strong dependence of the model's dynamical properties on the free parameters. Contrary to what is expected from non-linear modifications of general relativity of this kind, removal of the initial spacetime singularity is not a generic feature of the corresponding cosmological model. Instead, the starting point of the cosmic dynamics — the past attractor in the phase space — is a state of infinitely large value of the Hubble rate squared, usually associated with the big bang singularity.
Más información
Título de la Revista: | JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS |
Volumen: | 2010 |
Número: | February 2010 |
Editorial: | IOP PUBLISHING LTD |
Fecha de publicación: | 2009 |
Página de inicio: | 1 |
Página final: | 18 |
Idioma: | English |
DOI: |
http://dx.doi.org/10.1088/1475-7516/2010/02/027 |
Notas: | ISI |