# Evaporating primordial black holes as varying dark energy

## TL;DR

This paper explores how evaporating primordial black holes could mimic dark energy behavior, affecting cosmic expansion and potentially alleviating the H0 tension, with constraints consistent with standard cosmology.

## Contribution

It introduces a novel model linking PBH evaporation to dark energy dynamics and compares it with observational data to test its viability.

## Key findings

- PBH evaporation can be modeled as a time-varying dark energy component.
- The PBH model is statistically consistent with ΛCDM according to AIC.
- A population of ultra-light PBHs could modify expansion history and address H0 tension.

## Abstract

If light enough primordial black holes (PBH) account for dark matter, then its density decreases with time as they lose mass via Hawking radiation. We show that this time-dependence of the matter density can be formulated as an equivalent $w(z)$ dark energy model and we study its implications on the expansion history. Using our approach and comparing with the latest cosmological data, including the supernovae type Ia, Baryon Acoustic Oscillations, Cosmic Microwave Background and the Hubble expansion H(z) data, we place observational constraints on the PBH model. We find that it is statistically consistent with $\Lambda$CDM according to the AIC statistical tool. Furthermore, we entertain the idea of having a population of ultra-light PBHs, decaying around neutrino decoupling, on top of the dark matter fluid and show how this offers a natural dark matter-radiation coupling altering the expansion history of the Universe and alleviating the $H_0$ tension.