On the slow roll expansion for brane inflation
Abstract
One possibility for identifying the inflaton in the framework of string theory is that it is a D-brane modulus. This option involves a specific, non-canonical form of the kinetic energy—the Dirac Born Infeld action. This note investigates the applicability of the slow roll approximation in inflationary models of this type. To this end the slow roll expansion of Liddle, Parsons and Barrow is derived for the case of the DBI action. The resulting slow roll conditions augment the standard ones valid in the case of canonical kinetic terms. It is also shown that in DBI models inflation does not require that the potential dominate the energy density.
- Publication:
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Journal of Cosmology and Astroparticle Physics
- Pub Date:
- April 2007
- DOI:
- 10.1088/1475-7516/2007/04/018
- arXiv:
- arXiv:hep-th/0702118
- Bibcode:
- 2007JCAP...04..018S
- Keywords:
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- High Energy Physics - Theory
- E-Print:
- References added