New energy definition for higher-curvature gravities

We propose a novel but natural definition of conserved quantities for gravity models of quadratic and higher order in curvature. Based on the spatial asymptotics of curvature rather than of metric, it avoids the more egregious problems—such as zero-energy “theorems” and failure in flat backgrounds—in this fourth-derivative realm. In $D>4$, the present expression indeed correctly discriminates between second-derivative Gauss-Bonnet and generic, fourth-derivative actions.