Effects of Lovelock terms on the final fate of gravitational collapse: analysis in dimensionally continued gravity

TL;DR

This paper derives exact solutions in dimensionally continued Lovelock gravity showing that gravitational collapse of null dust can produce naked singularities, with their nature depending on the spacetime dimension.

Contribution

It provides the first analysis of gravitational collapse outcomes in Lovelock gravity, revealing dimension-dependent naked singularity formation.

Findings

Naked singularities can form during null dust collapse in Lovelock gravity.

In even dimensions, a massless null naked singularity appears.

In odd dimensions, a massive timelike naked singularity forms.

Abstract

We find an exact solution in dimensionally continued gravity in arbitrary dimensions which describes the gravitational collapse of a null dust fluid. Considering the situation that a null dust fluid injects into the initially anti-de Sitter spacetime, we show that a naked singularity can be formed. In even dimensions, a massless ingoing null naked singularity emerges. In odd dimensions, meanwhile, a massive timelike naked singularity forms. These naked singularities can be globally naked if the ingoing null dust fluid is switched off at a finite time; the resulting spacetime is static and asymptotically anti-de Sitter spacetime. The curvature strength of the massive timelike naked singularity in odd dimensions is independent of the spacetime dimensions or the power of the mass function. This is a characteristic feature in Lovelock gravity.