Quantum Gravity at the Crossroads

Abstract: Quantum gravity remains fragmented across scales and frameworks: at high energies, a number of alternative theories aim to describe the fundamental aspects of gravity; at low energies, effective field theory and observations can constrain departures from General Relativity in a largely theory-agnostic fashion.
Rather than treating these domains as separate, I will argue for a unifying approach that maps quantum gravity details at Planckian scales onto predictions for the low-energy effective field theory, thus establishing a common language to compare different quantum-gravity frameworks among each other and with low-energy constraints such as positivity bounds and observational/experimental data. Concretely, I will show how this map is provided by the renormalization group and how the latter can also be used to make predictions for black hole physics. At a more conceptual level, I will highlight how ideas developed across quantum gravity, effective field theory, and phenomenology can mutually inform and challenge one another.