An Apologia for Firewalls

TL;DR

This paper critically examines proposed alternatives to the black hole firewall, demonstrating their inconsistencies and emphasizing the challenges in resolving the firewall paradox within current theoretical frameworks.

Contribution

It shows the inconsistency of embedding black hole interiors into radiation or CFT Hilbert spaces and refines the firewall argument using large AdS black holes.

Findings

Embedding interior Hilbert space into radiation is inconsistent

Embedding semi-classical interior into CFT Hilbert space is inconsistent

Large AdS black holes sharpen the firewall argument

Abstract

We address proposed alternatives to the black hole firewall. We show that embedding the interior Hilbert space of an old black hole into the Hilbert space of the early radiation is inconsistent, as is embedding the semi-classical interior of an AdS black hole into any dual CFT Hilbert space. We develop the use of large AdS black holes as a system to sharpen the firewall argument. We also reiterate arguments that unitary non-local theories can avoid firewalls only if the non-localities are suitably dramatic.