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Updated: Jul 4, 2026

Gradient Echo Quantum Memory in Warm Atomic Vapor
Published on: November 11, 2013
Information is not lost in the evaporation of 2D black holes
Abhay Ashtekar1, Victor Taveras, Madhavan Varadarajan
1The Cosmos and Physics Department, The Pennsylvania State University, University Park, Pennsylvania 16802, USA. ashtekar@gravity.psu.edu
Abstract:
We analyze Hawking evaporation of the Callan-Giddings-Harvey-Strominger black holes from a quantum geometry perspective and show that information is not lost, primarily because the quantum space-time is sufficiently larger than the classical. Using suitable approximations to extract physics from quantum space-times we establish that (i) the future null infinity of the quantum space-time is sufficiently long for the past vacuum to evolve to a pure state in the future, (ii) this state has a finite norm in the future Fock space, and (iii) all the information comes out at future infinity; there are no remnants.
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