A scalable tripartite Wigner's friend scenario

TL;DR

This paper extends Wigner's friend thought experiment to a tripartite scenario, combining quantum simulation and real quantum computer experiments to explore observer-independent facts and their inherent tensions.

Contribution

It introduces a tripartite Wigner's friend scenario and demonstrates its implementation through quantum simulation and IBM quantum computers, providing empirical insights into quantum measurement issues.

Findings

Quantum simulations match theoretical predictions.

Experimental results show higher error rates due to quantum gate imperfections.

The scenario offers a new platform to study observer-dependent phenomena.

Abstract

Wigner's friend thought experiment is intended to reveal the inherent tension between unitary evolution and measurement collapse. On the basis of Wigner's friend experiment, Brukner derives a no-go theorem for observer-independent facts. We construct an extended Wigner's friend scenario including three laboratories, namely, Alice's laboratory, Bob's laboratory and Charlie's laboratory, where Alice, Bob and Charlie are standing outside the laboratories while their friends are placed inside their own laboratories. We consider quantum simulation via Q\# quantum programming and also realize the primary quantum circuits using IBM quantum computers. Then, we calculate the probabilities and corresponding statistical uncertainties. It has been shown that the results of quantum simulation are clearly consistent with theoretical values, while it has a slightly higher error rates for the experimental results of quantum computers mainly because of a series of quantum gates, especially CNOT gates.