Inflationary theory and pulsar timing investigations of primordial black holes and gravitational waves

TL;DR

This paper explores how inflationary models could produce primordial black holes and gravitational waves detectable by pulsar timing arrays, analyzing which theories are currently ruled out or will be tested soon.

Contribution

It assesses the compatibility of inflationary scenarios with primordial black hole formation and gravitational wave observations, highlighting the potential of pulsar timing arrays for testing these models.

Findings

Models with broad primordial power spectra are strongly constrained.

Some inflationary models are already ruled out by current data.

Future pulsar timing experiments will test additional theories.

Abstract

The gravitational waves measured at LIGO are presumed here to come from merging primordial black holes. We ask how these primordial black holes could arise through inflationary models while not conflicting with current experiments. Among the approaches that work, we investigate the opportunity for corroboration through experimental probes of gravitational waves at pulsar timing arrays. We provide examples of theories that are already ruled out, theories that will soon be probed, and theories that will not be tested in the foreseeable future. The models that are most strongly constrained are those with a relatively broad primordial power spectrum.