Improved Black Hole Fireworks: Asymmetric Black-Hole-to-White-Hole Tunneling Scenario

TL;DR

This paper analyzes a quantum gravity-inspired model of black hole to white hole tunneling, identifies its instabilities, and proposes a minimal modification to improve its physical plausibility, emphasizing the role of irreversibility.

Contribution

It introduces a time-asymmetric modification to the black hole fireworks scenario, addressing instabilities and highlighting the importance of irreversibility in gravitational collapse.

Findings

Identified instabilities in the original model.

Proposed a minimal modification to eliminate instabilities.

Emphasized the significance of irreversibility in collapse scenarios.

Abstract

A new scenario for gravitational collapse has been recently proposed by Haggard and Rovelli. Presenting the model under the name of black hole fireworks, they claim that the accumulation of quantum gravitational effects outside the horizon can cause the tunneling of geometry from a black hole to a white hole, allowing a bounce of the collapsing star which can eventually go back to infinity. In this paper we discuss the instabilities of this model and propose a simple minimal modification which eliminates them, as well as other related instabilities discussed in the literature. The new scenario is a time-asymmetric version of the original model with a time-scale for the final explosion that is shorter than m log m in Planck units. Our analysis highlights the importance of irreversibility in gravitational collapse which, in turn, uncovers important issues that cannot be addressed in detail without a full quantum gravity treatment.