Stringy instability inside the black hole

TL;DR

This paper demonstrates that inside a specific black hole model, a negative gradient of the dilaton field causes rapid folded string creation, suggesting the black hole interior is filled with these strings rather than being empty.

Contribution

It reveals that negative dilaton gradient inside the black hole leads to folded string formation, challenging the traditional view of a vacuum black hole interior.

Findings

Rapid creation of folded strings inside the black hole.

The black hole interior is filled with folded strings.

Negative dilaton gradient triggers string production.

Abstract

We show that negative $(\nabla \Phi)^2$, where $\Phi$ is the dilaton, leads to a rapid creation of folded strings. Consequently it appears that the interior of the $SL(2,\mathbb{R})_k/U(1)$ black hole is not empty, but is filled with folded strings.