Abstract
We discuss self-gravitating global O(3) monopole solutions associated with the spontaneous breaking of O(3) down to a global O(2) in an extended Gauss-Bonnet theory of gravity in () dimensions, in the presence of a nontrivial scalar field that couples to the Gauss-Bonnet higher curvature combination with a coupling parameter . We obtain a range of values for (in our notation and conventions), which are such that a global (Israel type) matching is possible of the space-time exterior to the monopole core with a de Sitter interior, guaranteeing the positivity of the Arnowitt-Deser-Misner (ADM) mass of the monopole, which, together with a positive core radius , are both dynamically determined as a result of this matching. It should be stressed that in the general relativity (GR) limit, where , and , such a matching yields a negative ADM monopole mass, which might be related to the stability issues the [Barriola-Vilenkin (BV)] global monopole of GR faces. Thus, our global monopole solution, which shares many features with the BV monopole, such as an asymptotic-space-time deficit angle, of potential phenomenological/cosmological interest, but has, par contrast, a positive ADM mass, has a chance of being a stable configuration, although a detailed stability analysis is pending.
- Received 26 December 2022
- Accepted 23 March 2023
DOI:https://doi.org/10.1103/PhysRevD.107.085014
Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.
Published by the American Physical Society