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arXiv · 2610.28359

Topological ModMax--AdS Black Holes: Extremality, Charge Normalization, and Limits of WGC Diagnostics

Saeed Noori Gashti·Behnam Pourhassan·Saheb Soroushfar
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Abstract

We study four-dimensional topological anti-de Sitter black holes sourced by ModMax electrodynamics and its sign-reversed counterpart. Distinguishing the field-strength amplitude from the conserved displacement flux fixes the charge normalization, potential, and first law. We classify the exact extremal roots for spherical, planar, and hyperbolic horizons; in particular, the hyperbolic ModMax branch has no upper-charge discriminant bound and contains a finite-charge zero-mass point. We also derive the unstable spherical null circular orbit and evaluate the local near-horizon AdS$_2$ Breitenlohner--Freedman index for an explicitly specified charged-scalar probe. These are classical diagnostics, not a WGC verdict: the model does not specify a charged-particle spectrum, an ultraviolet completion, or the global perturbation problem. The distance and de Sitter conjectures cannot be quantitatively tested with the fixed-coupling AdS data considered here.

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Saeed Noori Gashti, Behnam Pourhassan, Saheb Soroushfar. 2026-10-20. Topological ModMax--AdS Black Holes: Extremality, Charge Normalization, and Limits of WGC Diagnostics. https://arxiv.org/abs/2610.28359

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