Light Scalar Fields Foster Production of Primordial Black Holes
The study explores using light scalar fields alongside a primary field to create primordial black holes (PBHs) during inflation. While single-field models require extreme fine-tuning to match cosmic microwave background data, these multifield models offer a generic mechanism. The spectator field drives the amplification of curvature perturbations through tachyonic growth of isocurvature modes, providing a robust way to produce PBHs without severe parameter sensitivity.