Primordial Black Holes from Warm Inflation

Abstract

Primordial Black Holes (PBHs) serve as a unique probe to the physics of the early Universe phenomenon, cosmic inflation. In light of this, we study the formation of PBHs by the collapse of overdense perturbations generated during a model of warm inflation. Warm inflation is a description in which the inflaton dissipates into the radiation fields both during and after the inflationary phase. In our study, we discuss the role of the inflaton dissipation to the enhancement in the primordial power spectrum at the PBH scales. Our analysis shows that for some range of model parameters, we can produce an interesting abundance of tiny mass PBHs ($\sim 10^3$ g) for our warm inflation model. Further, we also discuss the constraints on the initial mass fraction of the generated PBHs and the possibility of Planck mass PBH relics to constitute the dark matter.