Principal Killing strings in higher-dimensional Kerr-NUT-(A)dS spacetimes

TL;DR

This paper constructs special stationary string solutions called 'principal Killing strings' in higher-dimensional Kerr-NUT-(A)dS spacetimes, revealing their role in extracting angular momentum from black holes.

Contribution

It introduces the concept of principal Killing strings in higher-dimensional Kerr-NUT-(A)dS spacetimes, utilizing hidden symmetries to find explicit solutions and analyze their physical effects.

Findings

Principal Killing strings stretch from infinity to the black hole horizon.

These strings extract angular momentum from rotating black holes.

The strings exert an asymptotic torque on the black holes.

Abstract

We construct special solutions of the Nambu-Goto equations for stationary strings in a general Kerr-NUT-(A)dS spacetime in any number of dimensions. This construction is based on the existence of explicit and hidden symmetries generated by the principal tensor which exists for these metrics. The characteristic property of these string configurations, which we call "principal Killing strings," is that they are stretched out from "infinity" to the horizon of the Kerr-NUT-(A)dS black hole and remain regular at the latter. We also demonstrate that principal Killing strings extract angular momentum from higher-dimensional rotating black holes and interpret this as the action of an asymptotic torque.