Gravity Theories with Lightlike Sources in D=3

TL;DR

This paper derives new solutions in three-dimensional gravity theories with lightlike sources, including asymptotically flat geometries and multiphoton configurations, expanding understanding of such models.

Contribution

It provides the first known asymptotically flat solutions in topologically massive gravity generated by lightlike sources, using both direct solving and boost techniques.

Findings

First asymptotically flat solutions with lightlike sources in topologically massive gravity.

Explicit metrics for multiphoton solutions are constructed.

Null boost methods yield limits on source energies in Einstein gravity.

Abstract

Spacetimes generated by a lightlike particle source for topologically massive gravity and its limits - Einstein gravity and the pure gravitational Chern-Simons model - are obtained both by solving the field equations and by infinite boosts of static metrics. The resulting geometries are the first known solutions of topologically massive gravity that are asymptotically flat and generated by compact matter sources. Explicit metrics describing various multiphoton solutions are also derived. For Einstein gravity, we also construct such solutions by null boost identifications of Minkowski space and thereby obtain limits on the energies of the sources.