Overcharging nonlinear electrodynamic black holes at linear order and the weak cosmic censorship conjecture
Chengcheng Liu, Sijie Gao
Abstract
Evidences have been found that the weak cosmic censorship conjecture could be violated if test particles with charge and angular momentum are injected into a black hole. However, second-order corrections and fine-tunings on the particle's parameters are required in previous studies, indicating that self-force and radiative effects must be taken into account. In this paper, we first consider a magnetically charged particle falling into an extremal Bardeen black hole, which is regular (with no singularity) and has a magnetic monopole at the center. We then investigate a general class of magnetic black holes associated with nonlinear electrodynamics. In all the cases, we show that the test particle with magnetic charge could overcharge the black hole, causing possible violation of the weak cosmic censorship conjecture. We also find that every spherically symmetric spacetime associated with a magnetic field can also be generated by an electric field. Moreover, if a magnetically charged black hole can be overcharged, the same spacetime containing an electrically charged black hole can also be overcharged. Although possible counterexamples to the weak cosmic censorship have been constructed previously in the literature, which always involved higher-order terms in particles' parameters, we find, for the first time, that linear terms are enough to make counterexamples.