Year: 1999
Type: article
Abstract: I show that cosmological perturbation spectra produced from quantum fluctuations in massless or self-interacting scalar fields during an inflationary era remain invariant under a two parameter family of transformations of the homogeneous background fields. This relates slow-roll inflation models to solutions which may be far from the usual slow-roll limit. For example, a scale-invariant spectrum of perturbations in a minimally coupled, massless field can be produced by an exponential expansion with $a\ensuremath{\propto}{e}^{\mathrm{Ht}},$ or by a collapsing universe with $a\ensuremath{\propto}(\ensuremath{-}{t)}^{2/3}.$
Author: David Wands
Institution: University of Portsmouth
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2111818973