Induced gravitational waves from slow-roll inflation after an enhancing phase

Abstract The primordial spectrum of fluctuations may present a large peak as result enhancing features during inflation. This include, but is not limited to, bumps in the inflaton's potential, phases ultra-slow-roll or turns multi-field space. However, many models, inflation does end immediately after feature and it likely to continue with second phase slow-roll. We show that resulting induced gravitational waves probe from inflationary phase, even if its amplitude too small directly induce detectable waves. because, there are sharp peaks spectrum, total wave simply sum by peaked scale-invariant spectra separately, cross terms interaction between these modes also become important. find such always have characteristic slope. discuss parameter space be probed future detectors presence signals.