Black Hole as a Wormhole Factory

TL;DR

This paper presents an exact classical solution in a quantum gravity model showing black holes can contain wormhole-like structures, potentially acting as microscopic wormhole factories and supporting the ER=EPR conjecture.

Contribution

It introduces the 'Black Wormhole' solution demonstrating black holes can have internal wormholes and suggests black holes may produce microscopic wormholes during evaporation.

Findings

Black hole states have interior wormholes that merge with horizons at a critical point.

Hawking temperature vanishes at the merge point, indicating thermodynamic stability.

Supports the idea that black holes can generate microscopic wormholes as part of quantum processes.

Abstract

On general grounds, one may argue that a black hole stops radiation at the Planck mass, where the radiated energy is comparable to the black hole's mass. And also, it has been argued that there would be a "wormhole-like" structure, known as "space-time foam", due to large fluctuations below the Planck length. In this paper, as an explicit example, we consider an exact classical solution which represents nicely those two properties in a recently proposed quantum gravity model based on different scaling dimensions between space and time coordinates. The solution, called "Black Wormhole", consists of two different states, depending on its mass M and an IR parameter omega: For the black hole state, a non-traversable wormhole occupies the interior region of the black hole around the singularity at the origin, whereas for the wormhole state, the interior wormhole is exposed to an outside observer as the black hole horizon is disappeared from evaporation. The black hole state becomes thermodynamically stable as it approaches to the merge point where the interior wormhole throat and the black hole horizon merges, and the Hawking temperature vanishes at the exact merge point. This solution suggests the "Generalized Cosmic Censorship" by the existence of a wormhole-like structure which protects the naked singularity even after the black hole evaporation. One could understand the would-be wormholes inside the black hole horizon as the results of microscopic wormholes created by "negative" energy quanta which have entered the black hole horizon in Hawking radiation processes: The quantum black hole could be a wormhole factory. It is found that this speculative picture may be consistent with the recent "ER=EPR" proposal for resolving the recent black hole entanglement debates.