Primordial Black Holes as a Probe of Cosmology and High Energy Physics

TL;DR

This review analyzes primordial black holes (PBHs) as crucial probes of cosmology, gravitational collapse, high-energy physics, and quantum gravity by focusing on their formation and evaporation. It synthesizes how PBHs constrain primordial inhomogeneities, cosmological phase transitions, and varying-$G$ theories, while also discussing the role of critical phenomena in collapse and the implications of Hawking radiation for cosmic-ray and gamma-ray observations. The work highlights that PBHs could reveal inflationary dynamics, QCD-era physics, and potential TeV-scale quantum gravity scenarios with extra dimensions, including collider- and cosmic-ray–produced black holes. Even if PBHs are not abundant, their theoretical and observational consequences provide stringent tests of Early-Universe physics and fundamental interactions with broad practical impact for cosmology and high-energy theory.

Abstract

Recent developments in the study of primordial black holes (PBHs) will be reviewed, with particular emphasis on their formation and evaporation. PBHs could provide a unique probe of the early Universe, gravitational collapse, high energy physics and quantum gravity. Indeed their study may place interesting constraints on the physics relevant to these areas even if they never formed.

Figures (6)

• Figure 1: Constraints on $\beta(M)$
• Figure 2: Constraints on $\epsilon(M)$
• Figure 3: Constraints on spectral index $n$ in terms of reheat time $t_1$
• Figure 4: Instantaneous emission from a 1 GeV black hole
• Figure 5: Spectrum of particles from uniformly distributed PBHs