Electromagnetic effect on anisotropic scalar field collapse in higher curvature gravity

TL;DR

This paper investigates how electromagnetic fields influence scalar field collapse in a higher curvature gravity theory, revealing that electromagnetic effects induce anisotropy and lead to hidden singularities.

Contribution

It introduces a novel analysis of scalar field collapse with electromagnetic effects in a four-dimensional scalar-Gauss-Bonnet gravity framework, highlighting anisotropic collapse solutions.

Findings

Electromagnetic fields induce anisotropy in the collapsing spacetime.

Collapse results in curvature singularities that are always hidden by apparent horizons.

The nature of the singularity (point-like or line-like) depends on anisotropy strength.

Abstract

We consider a `Scalar-Maxwell-Einstein-Gauss-Bonnet' theory in four dimension, where the scalar field couples non-minimally with the Gauss-Bonnet (GB) term. This coupling with the scalar field ensures the non topological character of the GB term. In such higher curvature scenario, we explore the effect of electromagnetic field on scalar field collapse. Our results reveal that the presence of a time dependent electromagnetic field requires an anisotropy in the background spacetime geometry and such anisotropic spacetime allows a collapsing solution for the scalar field. The singularity formed as a result of the collapse is found to be a curvature singularity which may be point like or line like depending on the strength of the anisotropy. We also show that the singularity is always hidden from exterior by an apparent horizon.