Lessons from the Information Paradox

Understand

We review recent progress on the information paradox.

• We explain why exponentially small correlations in the radiation emitted by a black hole are sufficient to resolve the original paradox put forward by Hawking.
• We then describe a refinement of the paradox that makes essential reference to the black-hole interior.
• This analysis leads to a broadly-applicable physical principle: in a theory of quantum gravity, a copy of all the information on a Cauchy slice is also available near the boundary of the slice.