PIRSA:26020045

Wigner's friend black hole adventure: an argument for complementarity?

Walleghem, L. (2026). Wigner's friend black hole adventure: an argument for complementarity?. Perimeter Institute. https://pirsa.org/26020045

Walleghem, Laurens. Wigner's friend black hole adventure: an argument for complementarity?. Perimeter Institute, Feb. 12, 2026, https://pirsa.org/26020045 

          @misc{ pirsa_PIRSA:26020045,
            doi = {10.48660/26020045},
            url = {https://pirsa.org/26020045},
            author = {Walleghem, Laurens},
            keywords = {Quantum Foundations},
            language = {en},
            title = {Wigner{\textquoteright}s friend black hole adventure: an argument for complementarity?},
            publisher = {Perimeter Institute},
            year = {2026},
            month = {feb},
            note = {PIRSA:26020045 see, \url{https://pirsa.org}}
          }

Laurens Walleghem University of York

Talk numberPIRSA:26020045
DOI10.48660/26020045
Collection
Talk Type Scientific Series
Subject

Abstract

At the heart of both Wigner's friend paradoxes and black hole puzzles lies the question of unitarity. In Wigner’s friend setups, sealed-lab measurements are modeled unitarily, probing the measurement problem. In black hole physics, the unitarity problem concerns information preservation in evaporation. In this talk, I discuss a refined version of the Frauchiger–Renner paradox and extend a recent analogy between Wigner's friend and black hole paradoxes exposed by Hausmann and Renner [arXiv:2504.03835v1], by constructing new paradoxes that merge black hole physics with nonlocal extensions of Wigner’s friend scenarios into a unified argument. I shortly discuss implications of these works, highlight some subtleties in black hole puzzles, and end with some speculations.