Primordial Black Holes and Gravitational Waves from Double-inflection-point Inflation

We propose a double inflection point inflationary model. In which one of the inflection point predicts the power spectra consistent with CMB observations at large scales and the other generates a large peak in the power spectrum of scalar perturbations at small scales.Such a peak allows for the generation of primordial black holes at small scales, which can account for a significant fraction of dark matter. We also calculate the energy spectrum of induce gravitational waves from primordial scalar perturbations and find that the gravitational-wave signal can be detected by future space-based laser interferometers.