Feasibility of Primordial Black Hole Remnants as Dark Matter in View of Hawking Radiation Recoil

TL;DR

This paper revisits the viability of primordial black hole remnants as dark matter, arguing that Hawking radiation recoil does not exclude them and that non-commutative spacetime effects could support their role as dark matter candidates.

Contribution

The study challenges previous claims by showing that black hole remnants remain plausible dark matter candidates, especially within non-commutative spacetime models, and estimates the relevant non-commutative scale.

Findings

Hawking radiation recoil does not disqualify black hole remnants as dark matter.

Non-commutative spacetime effects imply a non-commutative scale about 100 times the Planck length.

The analysis applies to black holes in asymptotically safe gravity with maximum temperature before cooling off.

Abstract

It has recently been suggested that black hole remnants of primordial origin are not a viable dark matter candidate since they would have far too large a velocity due to the recoil of Hawking radiation. We re-examined this interesting claim in more details and found that it does not rule out such a possibility. On the contrary, for models based on non-commutativity of spacetime near the Planck scale, essentially the same argument can be used to estimate the scale at which non-commutativity effect becomes important. If dark matter "particles" are non-commutative black holes that have passed the maximum temperature, this implies that the non-commutative scale is about 100 times the Planck length. The same analysis applies to other black hole remnants whose temperature reaches a maximum before cooling off, for example, black holes in asymptotically safe gravity.