# Restrictions for the Causal Inferences in an Interferometric System

## TL;DR

This paper applies causal discovery algorithms to a quantum delayed-choice experiment, revealing fundamental restrictions on classical causal models and highlighting the impossibility of certain objective interpretations without superluminal causation.

## Contribution

It demonstrates the use of causal discovery in quantum mechanics to identify constraints on classical causal models in a quantum delayed-choice experiment.

## Key findings

- Excludes models with two hidden variables.
- Shows the impossibility of objective wave-particle models without superluminal causation.
- Highlights restrictions on classical concepts in quantum systems.

## Abstract

Causal discovery algorithms allow for the inference of causal structures from probabilistic relations of random variables. A natural field for the application of this tool is quantum mechanics, where a long-standing debate about the role of causality in the theory has flourished since its early days. In this paper, a causal discovery algorithm is applied in the search for causal models to describe a quantum version of Wheeler's delayed-choice experiment. The outputs explicitly show the restrictions for the introduction of classical concepts in this system. The exclusion of models with two hidden variables is one of them. A consequence of such a constraint is the impossibility to construct a causal model that avoids superluminal causation and assumes an objective view of the wave and particle properties simultaneously.