Is there a classical model of Wigner's friend?

TL;DR

This paper critically examines claims that classical systems can replicate Wigner's friend paradoxes, emphasizing the importance of differing interpretations of probability in classical versus quantum contexts.

Contribution

It refutes recent claims that classical models can mimic quantum Wigner's friend effects by highlighting the misinterpretation of probability concepts.

Findings

Classical models cannot fully replicate Wigner's friend paradoxes.

Differences in probability interpretations are crucial in distinguishing classical and quantum scenarios.

The claim of classical mimicry is based on a misunderstanding of probability concepts.

Abstract

"Wigner's friend" refers to a quantum process of which different observers, following the rules of quantum mechanics, give contradictory descriptions. Lostaglio and Bowles have recently claimed to describe a classical system showing the same effect. It is argued that this claim is not justified. it fails to take into account the different meanings of probability in classical and quantum mechanics.