Cosmology with positive and negative exponential potentials
By Imogen Heard, D. Wands. 2002
143 citations recorded by the source corpus.
We present a phase-plane analysis of cosmologies containing a scalar field with an exponential potential V ∝ exp(−λ κ ) where κ2 = 8πG and V may be positive or negative. We show that power-law kinetic–potential scaling solutions only exist for sufficiently flat (λ2 6) negative potentials. The latter correspond to a class of ever-expanding cosmologies with negative potential. However, we show that these expanding solutions with a negative potential are unstable in the presence of ordinary matter, spatial curvature or anisotropic shear, and generic solutions always recollapse to a singularity. Power-law kinetic–potential scaling solutions are the late-time attractor in a collapsing universe for steep negative potentials (the ekpyrotic scenario) and stable against matter, curvature or shear perturbations. Otherwise kinetic-dominated solutions are the attractor during collapse (the pre-big-bang scenario) and are only marginally stable with respect to anisotropic shear.
Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/de07b82af73f494af8aef9ff5353f2fd37a9392f
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In Nuclear and High Energy Physics
Citations in the corpus
- Ekpyrotic and cyclic cosmology (2008, background): “The single-field cyclic model is an attractor, while at the same time managing to generate scalar perturbations that are nearly scale-invariant [93,42,39].”