| Автор | Imogen P C Heard |
| Автор | David Wands |
| Дата выпуска | 2002-11-07 |
| dc.description | We present a phase-plane analysis of cosmologies containing a scalar field φ with an exponential potential V ∝ exp(−λ κ φ) where κ<sup>2</sup> 8πG and V may be positive or negative. We show that power-law kinetic–potential scaling solutions only exist for sufficiently flat (λ<sup>2</sup> < 6) positive potentials or steep (λ<sup>2</sup> > 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. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Cosmology with positive and negative exponential potentials |
| Тип | paper |
| DOI | 10.1088/0264-9381/19/21/309 |
| Electronic ISSN | 1361-6382 |
| Print ISSN | 0264-9381 |
| Журнал | Classical and Quantum Gravity |
| Том | 19 |
| Первая страница | 5435 |
| Последняя страница | 5447 |
| Аффилиация | Imogen P C Heard; Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 2EG, UK |
| Аффилиация | David Wands; Institute of Cosmology and Gravitation, University of Portsmouth, Portsmouth PO1 2EG, UK |
| Выпуск | 21 |
