Firewall From Effective Field Theory

TL;DR

This paper investigates how non-renormalizable interactions in effective field theory near an evaporating black hole can lead to a firewall transition, challenging the stability of the horizon within the scrambling time.

Contribution

It demonstrates that higher-derivative operators cause exponential growth in transition amplitudes, leading to a firewall formation before the breakdown of effective field theory.

Findings

Transition amplitude grows exponentially after Hawking radiation appears

The horizon transitions to a firewall within the scrambling time

Effective field theory breaks down near the horizon due to higher-derivative effects

Abstract

For an effective field theory in the background of an evaporating black hole with spherical symmetry, we consider non-renormalizable interactions and their relevance to physical effects. The background geometry is determined by the semi-classical Einstein equation for an uneventful horizon where the vacuum energy-momentum tensor is small for freely falling observers. Surprisingly, after Hawking radiation appears, the transition amplitude from the Unruh vacuum to certain multi-particle states grows exponentially with time for a class of higher-derivative operators after the collapsing matter enters the near-horizon region, despite the absence of large curvature invariants. Within the scrambling time, the uneventful horizon transitions towards a firewall, and eventually the effective field theory breaks down.