English

Extended Wigner's friend paradoxes do not require nonlocal correlations

Quantum Physics 2025-11-18 v3

Abstract

Extended Wigner's friend no-go theorems provide a modern lens for investigating the measurement problem, by making precise the challenges that arise when one attempts to model agents as dynamical quantum systems. Most such no-go theorems studied to date, such as the Frauchiger-Renner argument and the Local Friendliness argument, are explicitly constructed using quantum correlations that violate Bell inequalities. In this work, we show that such correlations are not necessary for having extended Wigner's friend paradoxes, by constructing a no-go theorem utilizing a proof of the failure of noncontextuality. The argument hinges on a novel metaphysical assumption (which we term Commutation Irrelevance) that is a natural extension of a key assumption going into the Frauchiger and Renner's no-go theorem.

Keywords

Cite

@article{arxiv.2310.06976,
  title  = {Extended Wigner's friend paradoxes do not require nonlocal correlations},
  author = {Laurens Walleghem and Rafael Wagner and Yìlè Yīng and David Schmid},
  journal= {arXiv preprint arXiv:2310.06976},
  year   = {2025}
}

Comments

v3: closely aligned with published version in PRA. 7+4 pages, 1+1 figures. All comments welcome!

R2 v1 2026-06-28T12:46:31.572Z