Black Hole Information Puzzle


June 20 - 24, 2022

This workshop focuses on the “Black Hole Information Puzzle” and is part of the activities of the John Bell Institute for the Foundations of Physics during the summer of 2022. The objective of the event is to provide an encouraging environment to foster the discussion of the issues that arise within the various approaches towards dealing with the puzzle. In order to achieve this we have designed a framework that differs substantially from the usual arrangement based on an uninterrupted succession of talks (usually lasting at most one hour) and have replaced it with a scheme involving continuous discussion sessions lasting up to 3 hours where specific aspects of the problem will be addressed and discussed energetically but cordially and respectfully.

The program will be oriented along the following lines:

  1. What is the nature of the BH information paradox? What are the set of assumptions leading to the issue? What would be the implications of relaxing/modifying such assumptions?

  2. Discussion of approaches that aim at clarifying the issue directly from a bulk spacetime perspective. Problems and potential paths towards their resolution. Implication of different approaches.

  3. Approaches that aim at dealing with the issue from a holographic perspective (such as ADS-CFT). The underlying assumptions, outstanding issues and their possible resolution. The relationship if any to 2).

  4. Relationship with entropy. The GSL: conceptual and theoretical underpinning. Relevance of various notions of Entropy.

  5. Specific modeling. Rigorous results vs. ideas based on educated guesses.

We are of course open to enlarging or otherwise modifying the scheme based on input from participants. The declared objective is not to decide what approach is best, or who is smarter, but for everyone to leave with a clear picture of what each approach entails and what are the corresponding implications for our understanding of the rest of physics.

The list of participants includes:

  • Lautaro Amadei (Marseille)

  • Buro Costa (UNAM)

  • Benito Juarez Aubry (UNAM)

  • Steve Hsu (Michigan)

  • Bernard Kay (U. of York)

  • Elias Okón (UNAM)

  • Tim Maudlin (NYU)

  • Roger Penrose (Oxford)

  • Alejandro Perez (Marseille)

  • Surat Raju (ICTS, India)

  • Salvatore Ribisi (Marseille)

  • Franjo Sokolic (Split, Croatia)

  • Lee Smolin (Permeter I, Canada)

  • Simone Speziale (Marseille)

  • Daniel Sudarsky (UNAM)

  • Sami Viollet (Marseille)

  • Robert M. Wald (Chicago)

This worksop is co-organized by the Faculty of Science of the University of Split, Croatia.

For further information, please contact Alejandro Perez ( or Daniel Sudarsky (