Black holes, gravitational waves and fundamental physics: a roadmap

TL;DR

This paper provides a comprehensive overview of how gravitational wave astronomy, especially black hole observations, can test fundamental physics theories and address key cosmological questions, outlining future research directions.

Contribution

It offers a detailed roadmap for future research in gravitational physics, black holes, and gravitational wave science, highlighting open problems and potential breakthroughs.

Findings

Gravitational waves enable testing of black hole models and General Relativity.

Detection of gravitational waves confirms key predictions of Einstein's theory.

Future observations may uncover new fundamental fields or physics.

Abstract

The grand challenges of contemporary fundamental physics---dark matter, dark energy, vacuum energy, inflation and early universe cosmology, singularities and the hierarchy problem---all involve gravity as a key component. And of all gravitational phenomena, black holes stand out in their elegant simplicity, while harbouring some of the most remarkable predictions of General Relativity: event horizons, singularities and ergoregions. The hitherto invisible landscape of the gravitational Universe is being unveiled before our eyes: the historical direct detection of gravitational waves by the LIGO-Virgo collaboration marks the dawn of a new era of scientific exploration. Gravitational-wave astronomy will allow us to test models of black hole formation, growth and evolution, as well as models of gravitational-wave generation and propagation. It will provide evidence for event horizons and ergoregions, test the theory of General Relativity itself, and may reveal the existence of new fundamental fields. The synthesis of these results has the potential to radically reshape our understanding of the cosmos and of the laws of Nature. The purpose of this work is to present a concise, yet comprehensive overview of the state of the art in the relevant fields of research, summarize important open problems, and lay out a roadmap for future progress.