Inflation in DBI models with constant gamma

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.

V3: Extended and improved discussion, some new results, and additional references. V4: small improvements; same as the version published in JCAP

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Cited by in corpus (15)

• K-inflationary Power Spectra in the Uniform Approximation
• On the squeezed limit of the bispectrum in general single field inflation
• Cosmological Dynamics of a Dirac-Born-Infeld field
• Constraining non-minimally coupled tachyon fields by Noether symmetry
• Non-canonical generalizations of slow-roll inflation models
• Inflationary potentials in DBI models
• Warm DBI inflation with constant sound speed
• Resurrecting the Power-law, Intermediate, and Logamediate Inflations in the DBI Scenario with Constant Sound Speed
• Enhanced Inflation in the Dirac-Born-Infeld framework
• Anisotropic constant-roll inflation for the Dirac-Born-Infeld model
• Inflation with exotic kinetic terms in Einstein-Chern-Simons gravity
• Structure formation in clustering DBI dark energy model with constant sound speed
• DBI analog of a decaying vacuum cosmology
• Non-relativistic Matrix Inflation
• Inflationary predictions at small gamma