Hayden–Preskill Black Hole Recovery

Information recovery from old black holes modeled through scrambling and quantum decoding. The main concepts are scrambling time, mutual information, decoupling. Each must be defined in the context of a concrete physical model, mathematical representation, or experimental task. Terminology alone does not establish the behavior of the system.

The Hayden–Preskill thought experiment analyzes information recovery from a black hole modeled as a rapidly scrambling unitary process. The recovery task depends on whether the black hole is old, what early radiation the decoder possesses and the quality of control over emitted systems. Rapid information release after the scrambling time is conditional on these assumptions; it is not a general laboratory time estimate or a proven statement about arbitrary evaporating black holes.

Simulate a finite random unitary or local scrambling circuit with a reference entangled with the injected diary. Track reference mutual information and decoder fidelity against collected radiation size, comparing before and after a Page-like threshold. Separate an information-theoretic decoupling criterion from the physical complexity of implementing the recovery decoder.