Realization of a causal-modeled delayed-choice experiment using single photons

TL;DR

This paper experimentally demonstrates a causal-model based delayed-choice experiment using single photons, challenging wave-particle duality views without entanglement and highlighting the benefits of causal models in quantum theory.

Contribution

It presents the first experimental realization of a causal-modeled delayed-choice experiment with single photons, violating dimension witness inequalities without entanglement.

Findings

Successfully violated dimension witness inequalities

Demonstrated wave-particle objective in a causal model

Provided new insights into quantum theory from causal perspectives

Abstract

Wave-particle duality constitutes one of the most intriguing features in quantum physics. A well-known gedanken experiment that provides evidence for this is the Wheeler's delayed-choice experiment based on a Mach-Zehnder interferometer. Many different versions of delayed-choice experiments have been conducted with both classical and quantum detecting devices. Recently, it was proposed that the delayed-choice experiment could be devised from the perspective of device-independent prepare-and-measure scenario. In our work, we experimentally realize this modified version with a deterministic single-photon source, and examine the wave-particle objective in a causal-modeled scheme without assistance of entanglement, which is achieved by violating the dimension witness inequalities. Our experiment also provides an intriguing perspective and exhibits the benefits of studying quantum theory from the casual model point of view.