Charged nutty black holes are hairy

TL;DR

This paper reveals that Misner-Dirac strings in charged nutty black holes carry observable electromagnetic fields, creating a new type of classical hair and showing rotation can generate hair without NUT charge.

Contribution

It uncovers the physical nature of monopoles on Misner strings, demonstrating their role as observable electromagnetic hair in charged nutty black holes.

Findings

Misner-Dirac strings carry singular electric and magnetic field flows.

These strings create a short-range electromagnetic hair zone around the horizon.

Rotation can generate electromagnetic hair even without NUT charge.

Abstract

We uncover the physical nature of the electric and magnetic monopoles discovered by McGuire and Ruffini on Misner strings accompanying charged nutty black holes, showing that these strings carry singular, nonuniform flows of electric and magnetic fields. These fields inevitably have nonzero divergence, thereby simulating the effective electric and magnetic charge densities along the strings. The latter create a complex short-range electromagnetic hair zone around the horizon, making the combined Misner-Dirac strings classically observable. Typical features of this new type of hair are presented. We also note that rotation can act as a hair generator even in the absence of NUT.