Sharp turns in axion monodromy: primordial black holes and gravitational waves

Understand

Large turns in multifield inflation can lead to a very rich phenomenology, but are difficult to realise in supergravity, and typically require large field space curvatures.

• In this work, we present a mechanism to realise multiple sharp turns, and therefore strong non-geodesic trajectories, from transient violations of slow-roll without the requirement of large field space curvatures in supergravity inflation.
• Such turning rates can strongly source the adiabatic fluctuations, resulting in an enhanced scalar power spectrum with resonant features and a large peak amplitude.
• If the growth of the scalar power spectrum at small scales is large enough, primordial black holes can be produced in abundance.