Evolution of the Mass Spectrum of Primordial Black Holes in the Friedmann Universe

In this paper, we investigated the evolution of the mass spectrum of primordial black holes (PBHs) in the expanding Universe under the action of Bondi–Hoyle–Lyttleton accretion and Hawking radiation. For this paper, the initial mass spectrum of PBHs was assumed to be independent of mass. It was shown that accretion of matter surrounding a black hole does not significantly affect the growth of the mass of black holes. Using modeling, it was found that by the end of the radiation-dominated era, all primordial black holes with masses up to $$M=2\times 10^{9}$$ g had evaporated. This paper also confirmed the critical mass value for primordial black holes, at which they evaporate in our time. It is $$M_{\textrm{cr}}=1.4\times 10^{14}$$ g, if only photon emission is taken into account.