Hi all,

This week, Liuhang Ye will talk about “Geometric and Information-theoretic Aspects of the Black Hole Information Puzzle”, see below for the abstract. The seminar will take place on Tuesday in HIT H42 at 15:00.

Best, Ladina

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Title:

Geometric and Information-theoretic Aspects of the Black Hole Information Puzzle

Abstract:

Black holes provide a unique arena in which the principles of general relativity, quantum field theory and quantum information theory intersect. Hawking’s discovery that black holes radiate thermally, together with Bekenstein’s identification of horizon area with black hole entropy, gives rise to a profound tension between semi-classical gravity and unitarity of quantum theory - known as the black hole information puzzle. This thesis offers an in-depth investigation of the puzzle from both geometric and information-theoretic perspectives, aiming to clarify the logical structure underlying recent key developments.

In this presentation, I will explain the background of the information puzzle, and then review the replica method for calculating entropies in QFT, for both fixed and dynamical geometries. In ordinary QFT the replica geometry factorizes into independent copies of the single-sheet geometry, whereas in gravity the Lewkowycz–Maldacena prescription reveals non-factorizing “replica wormhole” saddles that lead to the Island formula. We discuss the connection between wormholes and the notion of elusive references arising from the quantum de Finetti theorem, providing operational meaning of the Page curve. Finally, the interplay between information and geometry is explored, and we conjecture that the elusive reference encountered in the black hole context is a distinctive feature of dynamical gravity, rooted in the non-factorizable geometries that emerge in the gravitational path integral.