Year: 2000
Type: article
Abstract: We contrast the possibility of inflation starting (a) from the universe's inception or (b) from an earlier noninflationary state. Neither case is ideal since (a) assumes that quantum mechanical reasoning is straightforwardly applicable to the early universe, while case (b) requires that a singularity still be present. Further, in agreement with Vachaspati and Trodden case (b) can only solve the horizon problem if the noninflationary phase has an equation of state $\ensuremath{\gamma}<4/3,$ thereby excluding radiation or massless scalar field dominated cases. Other alternative models, such as the smooth branch change in the pre-big-bang model, have related problems of requiring homogeneity over noncausally connected large scales.
Author: D. H. Coule
Institution: University of Portsmouth
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2008056250