Global monopoles in dilaton gravity

TL;DR

This paper investigates how global monopoles influence spacetime in string-inspired gravity models, revealing singularities with massless dilatons and long-range dilaton effects with massive dilatons, thus expanding understanding of topological defects in alternative gravity theories.

Contribution

It provides a detailed analysis of global monopoles in dilaton gravity, considering both massive and massless dilatons, which was not extensively studied before.

Findings

Massless dilaton leads to singular spacetime around monopoles.

Massive dilaton results in a long-range dilaton cloud.

Comparison with existing literature highlights new effects of monopoles in string gravity.

Abstract

We analyse the gravitational field of a global monopole within the context of low energy string gravity, allowing for an arbitrary coupling of the monopole fields to the dilaton. Both massive and massless dilatons are considered. We find that, for a massless dilaton, the spacetime is generically singular, whereas when the dilaton is massive, the monopole generically induces a long range dilaton cloud. We compare and contrast these results with the literature.