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arXiv · 2609.07576

Globally regular charged black holes in non-polynomial quasi-topological gravity with Born-Infeld electrodynamics

Hong-Lin Liu·Zhong-Wen Feng·Qing-Quan Jiang·Xia Zhou·Xue-Ling Mu
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Abstract

We construct exact static, spherically symmetric charged solutions in four-dimensional non-polynomial quasi-topological gravity coupled to Born-Infeld electrodynamics. We focus on the model $h(p)=p/(1+\ell^{2}p)$, whose vacuum branch develops a curvature singularity at a finite radius. We show that Born-Infeld nonlinearities can remove this singularity within a finite region of parameter space, yielding globally regular geometries with an asymptotically flat exterior and a finite-curvature AdS-type core. The regular sector contains both horizonless configurations and RBHs, separated by a degenerate-horizon boundary. We further identify a continuous branch of regular black holes with a triple-degenerate inner horizon and a simple outer event horizon, satisfying $\kappa_-=0$ and $\kappa_+\neq0$. This provides a converse example to cases in which introducing charge spoils the regularity of a vacuum regular black hole. In the present model, Born-Infeld electrodynamics instead removes the finite-radius singularity of a vacuum-singular gravitational branch while supporting globally regular charged geometries, including RBHs with nontrivial inner-horizon structure.

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Hong-Lin Liu, Zhong-Wen Feng, Qing-Quan Jiang, Xia Zhou, Xue-Ling Mu. 2026-09-07. Globally regular charged black holes in non-polynomial quasi-topological gravity with Born-Infeld electrodynamics. https://arxiv.org/abs/2609.07576

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