Singularities, Firewalls, and Complementarity

TL;DR

This paper reviews the firewall paradox in black hole physics, offers a new interpretation involving a migrating singularity, and discusses the timing of firewall formation relative to the Page and scrambling times.

Contribution

It proposes a novel interpretation where the singularity migrates toward the horizon, causing a firewall at the Page time, and challenges the idea that firewalls form at the scrambling time.

Findings

The singularity intersects the horizon at the Page time.

Firewall formation is linked to the migration of the singularity.

The paper questions the early formation of firewalls at the scrambling time.

Abstract

Almheiri, Marolf, Polchinski, and Sully, recently claimed that once a black hole has radiated more than half its initial entropy (the Page time), the horizon is replaced by a "firewall" at which infalling observers burn up, in apparent violation of the equivalence principle and the postulates of black hole complementarity. In this paper I review the arguments for firewalls, and give a slightly different interpretation of them. According to this interpretation the horizon has standard properties, but the singularity is non-standard. The growing entanglement of the black hole with Hawking radiation causes the singularity to migrate toward the horizon, and eventually intersect it at the page time. The resulting collision of the singularity with the horizon leads to the firewall. Complementarity applies to the horizon and not to the singular firewall. Almheiri, Marolf, Polchinski, and Sully conjecture that firewalls form much earlier then the Page time; namely at the scrambling time. I argue that there is no reason to believe this generalization, and good reason to think it is wrong. For most of this paper I will assume that the firewall argument is correct. In the last section before the conclusion I will describe reasons for having reservations.