Suppression of spacetime singularities in quantum gravity

Abstract

We investigate the requirement of suppressing spacetime geometries with a curvature singularity via destructive interference in the Lorentzian gravitational path integral as a constraint on the microscopic action for gravity. Based on simple examples of static spherically symmetric spacetimes, we demonstrate that complete singularity suppression in the path integral stipulates that the action for gravity be of infinite order in the curvature.