Primordial black hole driven cosmic acceleration

TL;DR

This paper introduces a mechanism where primordial black holes induce cosmic acceleration, potentially explaining inflation and the Hubble tension through their repulsive effects within a cosmological model.

Contribution

It demonstrates that primordial black holes with specific properties can drive cosmic acceleration phases, including inflation and early dark energy, within a consistent framework.

Findings

Ultra-light PBHs can trigger exponential inflation with exit and reheating.

PBHs near matter-radiation equality can serve as early dark energy.

The mechanism is robust across various black hole models.

Abstract

We propose a natural mechanism for cosmic acceleration driven by primordial black holes (PBHs) with repulsive behavior, within a ''Swiss Cheese'' cosmological framework. Considering regular black hole spacetimes such as Hayward, Bardeen, and Dymnikova-as well as the singular Schwarzschild-de Sitter case-we consistently find a robust PBH-driven cosmic acceleration phase. This phase ends either at an energy scale set by the PBH parameters or through black hole evaporation. Notably, one finds that ultra-light PBHs with $m < 5 \times 10^8 \, {\rm g}$ can trigger exponential inflation with graceful exit and reheating. Additionally, PBHs with $m \sim 10^{12} \, {\rm g}$ and abundances $0.107 < \Omega_{\rm PBH}^{\rm eq} < 0.5$ near matter-radiation equality can act as an early dark energy component, offering a potential resolution to the Hubble tension.