DBI inflation and warped black holes

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