Dark dimension, the swampland, and the dark matter fraction composed of primordial black holes

Black Holes as Dark Matter

While the energy of the universe has been established to be about 0.04 baryons, 0.24 dark matter and 0.72 dark energy, the cosmological entropy is almost entirely, about (1−10), from black holes and only 10 from everything else. This identification of all dark matter as black holes is natural in statistical mechanics. Cosmological history of dark matter is discussed. [email protected]

Primordial Black Holes as Dark Matter: the Power Spectrum and Evaporation of Early Structures

We consider the possibility that massive primordial black holes are the dominant form of dark matter. Black hole formation generates entropy fluctuations that adds a Poisson noise to the matter power spectrum. We use Ly-α forest observations to constrain this Poisson term in matter power spectrum, then we constrain the mass of black holes to be less than ∼ few × 10 M⊙. We also find that structu...

Black Holes as Dark Matter Annihilation “Boosters”

The presence and growth of Intermediate and Supermassive Black Holes modify the surrounding distribution of stars and Dark Matter, and inevitably affect the prospects for indirectly detecting Dark Matter through its annihilation products. We show here that under specific circumstances, Black Holes can act as Dark Matter annihilation “boosters”. In particular, we show that mini-spikes, i.e. Dark...

Dark Matter Accretion into Supermassive Black Holes

Collisional dark matter and the origin of massive black holes

If the cosmological dark matter is primarily in the form of an elementary particle which has mass m(p) and cross section for self-interaction sigma, then seed black holes (formed in stellar collapse) will grow in a Hubble time t(H) due to accretion of the dark matter to a mass, M(H) = sqrt[IC(9)(A)t(H)(sigma/G(3)m(p)c(2))] = 7.1x10(6)(sigma/m(p))(1/2)V(9/2)(c)t(1/2)(H,15) solar masses. Here I i...