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arXiv · 2503.24162

Characteristic initial value problems for the Einstein-Maxwell-scalar field equations in spherical symmetry

Thomas Mädler·Radouane Gannouji·Emanuel Gallo
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Abstract

The characteristic initial boundary problem is discussed in spherical symmetry for the Einstein-Maxwell-scalar field equations. It is formulated for an affine-null metric and the resulting field equations are cast into a hierarchical system of partial differential equations. The initial boundary value problem for a family of null hypersurfaces is specified for a timelike-null foliation at the central geodesic of spherical symmetry as well as for a double-null foliation where the corresponding boundary is a null hypersurface. For the latter, two distinct boundary value formulations arise -- one where the null boundary has zero Misner-Sharp mass and another one where the corresponding Misner-Sharp mass is nonzero. As an application, the nonextremal and the extremal Reissner-Nordstr\"om solution in null coordinates for a charged black hole and the Fisher-Janis-Newman-Winicour solution are derived.

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Thomas Mädler, Radouane Gannouji, Emanuel Gallo. 2025-03-31. Characteristic initial value problems for the Einstein-Maxwell-scalar field equations in spherical symmetry. https://doi.org/10.1103/f5fc-zpld

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