# Transparentizing Black Holes to Eternal Traversable Wormholes

## TL;DR

This paper constructs a gravity model showing how evaporating black holes can transition into eternal traversable wormholes, matching boundary theories and exploring their properties and higher-dimensional embeddings.

## Contribution

It introduces a explicit time-dependent bulk solution in 2D gravity that demonstrates black hole to wormhole transition and matches boundary descriptions, extending to 4D scenarios.

## Key findings

- Black hole to wormhole transition realized explicitly
- Eternal traversable wormholes are shown to be gapped and non-chaotic
- Higher-dimensional embedding and scattering properties discussed

## Abstract

We present the gravity description of evaporating black holes that end up with eternal traversable wormholes where every would-be behind horizon degree is available in asymptotic regions. The transition is explicitly realized by a time-dependent bulk solution in the two-dimensional Einstein-dilaton gravity. In this solution, the initial AdS$_2$ black hole is evolved into an eternal traversable wormhole free of any singularity, which may be dubbed as transparentization of black holes to eternal traversable wormholes. The bulk construction completely matches with the boundary description governed by the Schwarzian boundary theory. We also obtain solutions describing eternal traversable wormholes as well as excitations by an additional matter and graviton oscillations on eternal traversable wormholes, which show that the eternal traversable wormhole states are gapped and non-chaotic. Embedding the 2d solution into a 4d traversable wormhole connecting two magnetically charged holes, we discuss 4d scattering of a wave incident upon one end of the traversable wormhole.