Making near-extremal wormholes traversable

TL;DR

This paper demonstrates how to make near-extremal charged AdS black holes traversable wormholes by boundary coupling deformations, even in the extremal limit, with information transfer scaling with entropy.

Contribution

It introduces a method to render extremal black hole throats traversable by boundary couplings, extending previous non-extremal wormhole constructions.

Findings

Traversability can be achieved near extremality with tuning or scaling of boundary couplings.

The amount of information transmitted scales with the black hole's entropy.

Traversability persists even as the black hole approaches the extremal limit.

Abstract

We construct a traversable wormhole from a charged AdS black hole by adding a coupling between the two boundary theories. We investigate how the effect of this deformation behaves in the extremal limit of the black hole. The black holes have finite entropy but an infinitely long throat in the extremal limit. We argue that it is still possible to make the throat traversable even in the extremal limit, but this requires either tuning the field for which we add a boundary coupling close to an instability threshold or scaling the strength of the coupling inversely with the temperature. In the latter case we show that the amount of information that can be sent through the wormhole scales with the entropy.