Blandford-Znajek process in vacuo and its holographic dual

TL;DR

This paper explores a vacuum electromagnetic energy transfer process around simplified black hole models and its holographic dual, linking black hole physics with boundary field theories in a novel, theoretical context.

Contribution

It introduces a vacuum-based Blandford-Znajek-like mechanism in lower-dimensional black holes and describes its holographic dual involving energy transfer in a thermal state.

Findings

Vacuum electromagnetic fields can transfer energy in simplified black hole models.

Holographic dual describes angular momentum transfer via resistive coupling.

Entropy increase matches Bekenstein-Hawking entropy change.

Abstract

Blandford and Znajek discovered a process by which a spinning black hole can transfer rotational energy to a plasma, offering a mechanism for energy and jet emissions from quasars. Here we describe a version of this mechanism that operates with only vacuum electromagnetic fields outside the black hole. The setting, which is not astrophysically realistic, involves either a cylindrical black hole or one that lives in 2+1 spacetime dimensions, and the field is given in simple, closed form for a wide class of metrics. For asymptotically Anti-de Sitter black holes in 2+1 dimensions the holographic dual of this mechanism is the transfer of angular momentum and energy, via a resistive coupling, from a rotating thermal state containing an electric field to an external charge density rotating more slowly than the thermal state. In particular, the entropy increase of the thermal state due to Joule heating matches the Bekenstein-Hawking entropy increase of the black hole.