Gedanken Experiments involving Black Holes

TL;DR

The paper argues for black hole complementarity, positing a stretched horizon that stores infalling information and thermalizes it for external emission, while observers crossing the horizon experience no drastic anomalies. It shows that attempting to detect or refute the stretched horizon with outside experiments typically necessitates Planck-scale physics, making such tests ineffective within known theories. By analyzing Rindler space, finite-mass collapse geometries, information retention times, and time-reversal scenarios, the authors argue that quantum information is conserved and inconsistencies only arise from extrapolations beyond Planck-scale physics. They conclude that a resolution to the information paradox likely requires a new quantum gravity framework, rather than local quantum field theory alone.

Abstract

Analysis of several gedanken experiments indicates that black hole complementarity cannot be ruled out on the basis of known physical principles. Experiments designed by outside observers to disprove the existence of a quantum-mechanical stretched horizon require knowledge of Planck-scale effects for their analysis. Observers who fall through the event horizon after sampling the Hawking radiation cannot discover duplicate information inside the black hole before hitting the singularity. Experiments by outside observers to detect baryon number violation will yield significant effects well outside the stretched horizon.