Nonperturbative definition of quantum gravity

Develop a well-defined, nonperturbative formulation of quantum gravity that does not rely on perturbation theory in the Newton constant (i.e., beyond graviton-loop expansions).

Background

In discussing how classical results might extend to quantum gravity, the paper highlights a fundamental limitation: current formulations are mainly perturbative in the Newton constant and rely on graviton-loop expansions. This restriction motivates looking for a nonperturbative definition that could underpin a robust notion of quantum subsystems and their algebras.

The author notes that while perturbative algebraic approaches (e.g., pAQFT with BV-BRST) provide local field algebras around fixed backgrounds, a fully nonperturbative construction remains absent. A solution to this problem would enable a more complete and background-independent framework for gravitational subsystems.