Effective black-to-white hole bounces: The cost of surgery

Understand

We investigate possible geometries allowing transitions from a black hole to a white hole spacetime, by placing a space-like thin shell between them.

• Such proposals have been advanced recently to account for singularity-resolution in black-hole spacetimes.
• This space-like shell can be extended to be outside the event horizon and, thereby, reproduce some of the features of these proposals.
• On the other hand, if the space-like shell is confined fully within the horizon, then it results in a bounce near a space-like singularity inside the black hole.