Test of the weak cosmic censorship conjecture with a charged scalar field and dyonic Kerr-Newman black holes

TL;DR

This paper revisits a thought experiment testing the weak cosmic censorship conjecture with charged scalar fields and dyonic Kerr-Newman black holes, confirming that the conjecture holds and black holes cannot be overcharged or overspun past extremality.

Contribution

It provides a new derivation based on conservation laws and energy conditions, reaffirming that cosmic censorship is not violated in these scenarios.

Findings

Weak cosmic censorship is not violated by charged scalar fields.

The derivation uses conservation laws and energy conditions.

The result is consistent with earlier simpler analyses.

Abstract

A thought experiment considered recently in the literature, in which it is investigated whether a dyonic Kerr-Newman black hole can be destroyed by overcharging or overspinning it past extremality by a massive complex scalar test field, is revisited. Another derivation of the result that this is not possible, i.e. the weak cosmic censorship is not violated in this thought experiment, is given. The derivation is based on conservation laws, on a null energy condition, and on specific properties of the metric and the electromagnetic field of dyonic Kerr-Newman black holes. The metric is kept fixed, whereas the dynamics of the electromagnetic field is taken into account. A detailed knowledge of the solutions of the equations of motion is not needed. The approximation in which the electromagnetic field is fixed is also considered, and a derivation for this case is also given. In addition, an older version of the thought experiment, in which a pointlike test particle is used, is revisited. The same result, namely the non-violation of the cosmic censorship, is rederived in a way which is simpler than in earlier works.