Year: 2008
Type: article
Abstract: Dirac–Born–Infeld scalar field theories which appear in the context of inflation in string theory in general have a field-dependent speed of sound. It is, however, possible to write down DBI models which possess exact solutions characterized by a constant speed of sound different from unity. This requires that the potential and the effective D -brane tension appearing in a DBI action have to be related in a specific way. This paper describes such models in general and presents some examples with a constant speed of sound c s <1 for which the spectrum of scalar perturbations can be found analytically without resorting to the slow-roll approximation.
Author: Michał Spaliński
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W1851064026