Measuring the Black Hole Interior from the Exterior

TL;DR

This paper proposes that an external observer can reconstruct the interior geometry of a black hole using holographic principles and entanglement entropy, revealing deep correlations between interior and exterior degrees of freedom.

Contribution

It introduces a method to infer black hole interiors from outside measurements based on holographic duality and entanglement entropy, advancing understanding of black hole information.

Findings

External measurements can reconstruct black hole interior geometry.

Holographic duality links timelike and spacelike entanglement entropy.

Interior and exterior degrees of freedom are fundamentally correlated.

Abstract

In this essay, we argue that an observer outside the horizon can reconstruct the geometry of a black hole's interior through external measurements. This procedure builds on recent studies of the holographic duality of timelike entanglement entropy and its connection to spacelike entanglement entropy. Furthermore, we propose that this phenomenon reveals a fundamental correlation between the degrees of freedom inside and outside the black hole at the level of classical spacetime.