Speaker
Description
We study the possibility of reheating the universe in its early stages through the evaporation of
Primordial Black Holes (PBHs) that are formed due to the collapse of the inhomogeneities that
were generated during inflation. By using the current results of the baryon-photon ratio obtained
from BBN and CMB observations, we impose constraints on the spectral index of perturbations on
those small scales that cannot be estimated through CMB anisotropy and CMB distortions. The
masses of the PBHs constrained in this study lie in the range of $10^9$ and $10^{11}$g, which corresponds
to those PBHs whose maximal evaporation took place during the redshifts $10^6$ < z < $10^9$. It is
shown that the upper bound on the scalar spectral index, $n_s$ can be constrained for a given threshold
value, $\zeta_{th}$, of the curvature perturbations for PBHs formation. Using Planck results for cosmological
parameters we obtained $n_s$ < 1.309 for $\zeta_{th}$ = 0.7 and $n_s$ < 1.334 for $\zeta_{th}$ = 1.2 respectively. The
density fraction that has contributed to the formation of Primordial Black Holes has also been
estimated.
