A quantum experiment with joint exogeneity violation

TL;DR

This paper demonstrates a violation of the joint exogeneity assumption in a quantum experiment, challenging a key assumption in randomized experiments and highlighting the limits of classical physics in such contexts.

Contribution

It provides the first empirical evidence of joint exogeneity violation in a quantum setting, questioning its validity in regimes beyond classical physics.

Findings

Violation of joint exogeneity observed in quantum experiment

Implications for potential outcome modeling in quantum regimes

Challenges classical assumptions in randomized experiments

Abstract

In randomized experiments, the assumption of potential outcomes is usually accompanied by the \emph{joint exogeneity} assumption. Although joint exogeneity has faced criticism as a counterfactual assumption since its proposal, no evidence has yet demonstrated its violation in randomized experiments. In this paper, we reveal such a violation in a quantum experiment, thereby falsifying this assumption, at least in regimes where classical physics cannot provide a complete description. We further discuss its implications for potential outcome modelling, from both practial and philosophical perspectives.