Detector operators in quantum gravity

What is the full set of observables in quantum gravity? I will introduce and discuss asymptotic detector operators and their measurements in perturbative quantum gravity in asymptotically-flat spacetimes. The simplest example is an energy detector, which detects outgoing graviton radiation and records its energy. I will construct large classes of general detector operators in QFT and in gravity, defined as light-ray operators. I will present the first computation of an energy-energy correlator (EEC) as well as some of its generalizations in perturbative quantum gravity. One can think of such observables as capturing a universal part of quantum correlations between idealized LIGO detectors — as unlikely as it may be to be measured in the real world. Along the way, I will comment on the "space of asymptotic detector operators" in a gravitational theory.