Probing the quantum nature of gravity

The recent first image of a black-hole shadow by the EHT Collaboration [1] and observations of gravitational waves from black-hole mergers by the LIGO/VIRGO-collaboration [2] challenge our understanding of gravity in an unprecedented way: In the theory of General Relativity, black holes harbor a singularity of spacetime, i.e., infinite gravitational forces. Such a mathematical infinity has no physical meaning. Instead it signals the breakdown of General Relativity. To describe the true nature of black holes, and the microscopic structure of spacetime, General Relativity must be unified with quantum theory in a fundamental theory of quantum gravity. This will describe gravity in its most extreme regimes, e.g., black holes, the very early universe and very high energetic interactions
of elementary particles, answering some of the most fascinating mysteries about our universe. To me,
probing the quantum nature of gravity is a truly exciting challenge, now made possible by recent
theoretical and observational advances, sparking as well as facilitating my three key objectives: