Firewalls from wormholes

TL;DR

The paper investigates whether spacetime wormholes can drive old black holes to tunnel into white holes (firewalls) within JT gravity. It develops a genus-one (handle-disk) wormhole computation to quantify the firewall probability, showing it scales as $P_{\text{firewall}}(t) \sim \tfrac{1}{2}(t/2\pi)^2 e^{-2S}$ at fixed energy, arising from baby-universe emission, and balances against negative contributions to preserve exact unitarity. The analysis combines disk-only results, a detailed genus-one moduli-space treatment, and a careful no-shortcut interior gauge to yield a full physical-length distribution $P(L)$, revealing a sharp firewall peak at $L=\ell_t$ with a time-growing tail. The work connects late-time black-hole physics, the spectral form factor, and interior gauge choices, and discusses open questions about late-time saturation, higher-genus corrections, and the boundary dual interpretation, including half-wormhole perspectives. Overall, it provides a concrete, calculable mechanism by which old black holes can acquire firewall-like features through wormhole-induced baby-universe processes, with precise probabilistic scaling and normalization discussed.

Abstract

Spacetime wormholes can lead to surprises in black hole physics. We show that a very old black hole can tunnel to a white hole/firewall by emitting a large baby universe. We study the process for a perturbed thermofield double black hole in Jackiw-Teitelboim (JT) gravity, using the lowest order (genus one) spacetime wormhole that corresponds to single baby-universe emission. The probability for tunneling to a white hole is proportional to $t^2 e^{-2S}$ where $t$ is the age of the black hole and $S$ is the entropy of one black hole.