Signals of primordial black holes at gravitational wave interferometers

TL;DR

This paper explores how future gravitational wave detectors can identify signals from primordial black holes across a wide mass range, providing new constraints on early universe conditions and PBH formation scenarios.

Contribution

It demonstrates the potential of next-generation GW experiments to probe primordial black hole formation and their associated gravitational wave signatures across a broad mass spectrum.

Findings

GW detectors can constrain PBH parameters for masses 1e9 - 1e27 g.

Detection of stochastic GW background can limit primordial power spectrum.

Light PBHs may temporarily dominate the universe's energy density before evaporating.

Abstract

Primordial black holes (PBHs) can form as a result of primordial scalar perturbations at small scales. This PBH formation scenario has associated gravitational wave (GW) signatures from second-order GWs induced by the primordial curvature perturbation, and from GWs produced during an early PBH dominated era. We investigate the ability of next generation GW experiments, including BBO, LISA, and CE, to probe this PBH formation scenario in a wide mass range. Measuring the stochastic GW background with GW observatories can constrain the allowed parameter space of PBHs for masses 1e9 - 1e27 g. We also discuss possible GW sources from an unconstrained region where light PBHs (< 1e9 g) temporarily dominate the energy density of the universe before evaporating. We show how PBH formation impacts the reach of GW observatories to the primordial power spectrum and provide constraints implied by existing PBH bounds.