DBI Inflation and Warped Black Holes

Abstract

We study a possible amplification mechanism for the curvature perturbations generated during inflation by a Dirac-Born-Infeld (DBI) inflaton in the presence of a sharp feature in the warp factor. The large growth resulting in the scalar power spectrum is a consequence of the decreasing speed of sound. We obtain analytical approximate expressions for the relevant dynamical quantities both in the slow roll phase and during the transient phase which leads to the amplification. We finally compare our approximations to the exact numerical evolution and give, in such a context, the general rules for building a viable inflationary model leading to, during the subsequent radiation dominated era, an abundant primordial black holes formation.

27 pages, 5 figures. Final version accepted for publication on JCAP

References in corpus (6)

• Observational Signatures and Non-Gaussianities of General Single Field Inflation
• Primordial black hole dark matter from single field inflation
• Primordial Black Holes and Slow-Roll Violation
• Quantum modes in DBI inflation: exact solutions and constraints from vacuum selection
• Non-Gaussianity in single field models without slow-roll
• A Consistency Relation for Power Law Inflation in DBI models

Cited by in corpus (7)

• Inflation and Primordial Black Holes
• Swampland conjectures in hybrid metric-Palatini gravity
• Inflation with $0\le c_{\mathrm{s}}\le 1$
• Primordial Black Hole Formation in Non-Standard Post-Inflationary Epochs
• Growth of power spectrum due to decrease of sound speed during inflation
• Reconstruction methods and the amplification of the inflationary spectrum
• Primordial black hole formation in k-inflation models