Shock waves and Birkhoff's theorem in Lovelock gravity

TL;DR

This paper demonstrates the existence of spherically symmetric shock waves in Lovelock gravity, which involve a branch change across a null hypersurface, raising questions about the validity of Birkhoff's theorem in this context.

Contribution

It introduces the existence of shock waves in Lovelock gravity and discusses their implications for Birkhoff's theorem, a novel insight in higher-order gravity theories.

Findings

Shock waves exist in Lovelock gravity.

Shock waves involve a branch change across a null hypersurface.

Implications challenge the traditional understanding of Birkhoff's theorem.

Abstract

Spherically symmetric shock waves are shown to exist in Lovelock gravity. They amount to a change of branch of the spherically symmetric solutions across a null hypersurface. The implications of their existence for the status of Birkhoff's theorem in the theory is discussed.