AdS/CFT and the Information Paradox

TL;DR

This paper explores how the AdS/CFT correspondence provides insights into the black hole information paradox, suggesting that quantum effects and non-locality resolve apparent contradictions in black hole evaporation.

Contribution

It demonstrates that unitarity in the CFT implies information retrieval from black holes and discusses the necessity of non-local effects to resolve redundancies in semi-classical theories.

Findings

Information is preserved and returned in Hawking radiation.

Non-local quantum effects are essential to eliminate degrees of freedom redundancy.

Classical-quantum correspondence breaks down in Lorentzian black hole spacetimes.

Abstract

The information paradox in the quantum evolution of black holes is studied within the framework of the AdS/CFT correspondence. The unitarity of the CFT strongly suggests that all information about an initial state that forms a black hole is returned in the Hawking radiation. The CFT dynamics implies an information retention time of order the black hole lifetime. This fact determines many qualitative properties of the non-local effects that must show up in a semi-classical effective theory in the bulk. We argue that no violations of causality are apparent to local observers, but the semi-classical theory in the bulk duplicates degrees of freedom inside and outside the event horizon. Non-local quantum effects are required to eliminate this redundancy. This leads to a breakdown of the usual classical-quantum correspondence principle in Lorentzian black hole spacetimes.