Black Hole Information, Replica Wormholes, and Macroscopic Entanglement

TL;DR

This review explores how replica wormholes and quantum hair effects influence black hole evaporation, showing that macroscopic entanglement can resolve the information paradox and produce pure, highly entangled Hawking radiation states.

Contribution

It highlights the role of replica wormholes and quantum hair in understanding black hole information retrieval and resolves longstanding paradoxes through macroscopic entanglement.

Findings

Hawking radiation can form a pure, highly entangled macroscopic superposition.

Replica wormhole calculations reproduce the entanglement structure of radiation.

Macroscopic entanglement offers a resolution to the black hole information paradox.

Abstract

In this invited review, we discuss the evaporation of a black hole, with emphasis on the resulting macroscopically distinct patterns of Hawking radiation. The density matrix of this radiation can approach a pure final state in the form of a highly entangled macroscopic superposition state. We note that this exact property is exhibited in replica wormhole calculations, and also in quantum hair effects on Hawking radiation amplitudes. Finally, we revisit the information paradox (Mathur's theorem and firewalls), showing that it can be resolved by macroscopic entanglement.