Primordial Black Holes as Dark Matter

Understand

We investigate models in which a spectrum of black holes with Hawking temperature of order the radiation temperature at the beginning of the radiation dominated era can survive long enough to produce a matter dominated era at the observed crossover between matter and radiation in our universe.

• We find that a sufficiently dense population of such black holes can indeed do so.
• The stronger observational constraint, that the black holes have lifetimes at least as long as the current age of the universe is harder to assess, because of black hole mergers during the matter dominated era.
• We then investigate whether the required densities and masses are consistent with the Holographic Space-time (HST) model of inflation.