Dymnikova Black Holes in Unimodular Gravity: Maxwell Sources and Vacuum Contributions

TL;DR

This paper explores Dymnikova regular black holes within unimodular gravity, showing they can be supported by Maxwell electrodynamics with a localized charge and a dynamic vacuum contribution affecting the geometry.

Contribution

It demonstrates that Dymnikova black holes can be modeled by Maxwell sources in unimodular gravity, incorporating a radially dependent cosmological term and non-asymptotic charge behavior.

Findings

The geometry can be generated by Maxwell electrodynamics in unimodular gravity.

The electric field is regular everywhere and corresponds to a localized charge.

The spacetime does not exhibit asymptotic charge behavior.

Abstract

In this work, we investigate the Dymnikova regular black hole within the framework of unimodular gravity, emphasizing the role of the effective vacuum sector in the regularization of the geometry. By allowing a controlled violation of the covariant conservation of the energy--momentum tensor, the cosmological contribution emerges dynamically as a radial-dependent function, $\Lambda=\Lambda(r)$. We first reinterpret the Dymnikova spacetime as a charged configuration supported by nonlinear electrodynamics and derive the corresponding electric and magnetic sources. Subsequently, we demonstrate that the same geometry can be consistently generated by standard Maxwell electrodynamics in unimodular gravity. In this construction, the resulting electric field is everywhere regular and corresponds to a localized charge distribution with vanishing asymptotic charge, indicating that the spacetime does not behave as an asymptotically charged object.