Primordial black holes with mass 1016−1017g and reionization of the Universe

Primordial Black Holes in an Accelerating Universe

General expressions are given for the generation of Primordial Black Holes (PBH) in a universe with a presently accelerated expansion due to a(n effective) cosmological constant. We give expressions both for a powerlaw scalefree primordial spectrum and for spectra which are not of that type. Specializing to the case of a pure cosmological constant Λ and assuming flatness, we show that a comolog...

Primordial Black Holes, Hawking Radiation and the Early Universe

Probability for Primordial Black Holes in Higher Dimensional Universe

We investigate higher dimensional cosmological models in the semiclassical approximation with Hartle-Hawking Boundary conditions, assuming a gravitational action which is described by the scalar curvature with a cosmological constant. In the framework the probability for quantum creation of an inflationary universe with a pair of black holes in a multidimensional universe is evaluated. The prob...

Primordial Black Holes and Primordial Nucleosynthesis I: Effects of Hadron Injection from Low Mass Holes

We investigate the influence of hadron injection from evaporating primordial black holes (PBHs) in the early stage of the primordial nucleosynthesis era (t ≃ 10−3 − 104 sec). The emitted quark-antiquark pairs or gluons immediately fragment into a lot of hadrons and scatter off the thermal plasma which is constituted by photons, electrons and nucleons. For the relatively low mass holes we point ...

New calculation of the mass fraction of primordial black holes

We revisit the calculation of the abundance of primordial black holes ~PBHs! formed from primordial density perturbations, using a formation criterion derived by Shibata and Sasaki which refers to a metric perturbation variable rather than the usual density contrast. We implement a derivation of the PBH abundance which uses peaks theory, and compare it to the standard calculation based on a Pre...