Formation of Primordial Black Holes from Warm Inflation

Understand

Primordial Black Holes (PBHs) serve as a unique probe to the physics of the early Universe, particularly inflation.

• In light of this, we study the formation of PBHs by the collapse of overdense perturbations generated during a model of warm inflation.
• For our model, we find that the primordial curvature power spectrum is red-tilted (spectral index $n_s<1$) at the large scale (small $k$) and is consistent with the $n_s-r$ values allowed from the CMB observations.
• Along with that, it has a blue-tilt ($n_s>1$) for the small PBH scales (large $k$), with a sufficiently large amplitude of the primordial curvature power spectrum required to form PBHs.