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The latest observation of the Cosmic Microwave Background (CMB) sky constrains the epoch of inflation in the early universe to have a simple slow-roll dynamics that leads to tiny, nearly scale-invariant scalar fluctuations and even tinier tensor fluctuations. However, CMB can only probe large cosmological scales, so that the smaller scales that exit the inflationary horizon closer to the end of inflation remain unexplored by direct observational techniques. Scalar and tensor fluctuations can have peaks and features at small scales when the dynamics of inflation deviates from standard slow-roll. In particular, large scalar fluctuations can result in abundant primordial black holes (PBH) after inflation and can induce large tensor fluctuations that are realised as stochastic background of induced gravitational waves (GW). With the tremendous sensitivities proposed by upcoming GW surveys and several bounds on the abundance of PBH over a huge range of masses, it is exciting to analyse relevant inflation models for their predictions for PBH and induced GW. I will elaborate on a specific example of multifield axion monodromy model of inflation, where large and sharp turns in the field-space manifold lead to enhanced scalar fluctuations. Apart from inflationary history, non-standard post-inflationary evolution can also influence the predictions for PBH and GW, which I will also discuss. |