Piecewise flat gravitational waves

Abstract

We examine the continuum limit of the piecewise flat locally finite gravity model introduced by ’t Hooft. In the linear weak field limit, we find the energy–momentum tensor and metric perturbation of an arbitrary configuration of defects. The energy–momentum turns out to be restricted to satisfy certain conditions. The metric perturbation is mostly fixed by the energy–momentum except for its lightlike modes which reproduce linear gravitational waves, despite no such waves being present at the microscopic level.