Anti-de Sitter massless scalar field spacetimes in arbitrary dimensions

TL;DR

This paper constructs and analyzes exact solutions of Einstein gravity with a massless scalar field in arbitrary dimensions, revealing naked singularities with finite mass in asymptotically anti-de Sitter spacetimes.

Contribution

It provides explicit solutions for Einstein-scalar systems with negative cosmological constant in arbitrary dimensions, including the calculation of finite mass and scalar contributions.

Findings

Solutions exhibit naked singularities without horizons.

The mass of these spacetimes is finite and well-defined.

The scalar field influences the asymptotic structure and mass contribution.

Abstract

We consider $d$-dimensional static spacetimes in Einstein gravity with a cosmological constant in the presence of a minimally coupled massless scalar field. The spacetimes have a $(d-2)$-dimensional base manifold given by an Einstein space and the massless scalar field depends only on the radial coordinate. The field equations are decoupled in the general case, and can be solved exactly for the cases when either the cosmological constant vanishes or the base manifold is Ricci flat. We focus on the case of a negative cosmological constant and a Ricci-flat base manifold. The solution has a curvature singularity located at the origin, where also the scalar field diverges. Since there is no event horizon surrounding this singularity, the solution describes a naked singularity dressed with a nontrivial scalar field. This spacetime is an asymptotically locally anti-de Sitter one when the Ricci-flat base manifold is locally flat. The asymptotic solution for an arbitrary Einstein base manifold is found and the corresponding mass, calculated through the canonical generator of the time-translation invariance, is shown to be finite. The contribution to the mass from the scalar field at infinity is also discussed.