Comment on Y. Couder and E. Fort: "Single-Particle Diffraction and Interference at a Macroscopic Scale", Phys. Rev. Lett. (2006)

TL;DR

This paper critiques a 2006 experiment with bouncing droplets mimicking quantum interference, arguing the data are unconvincing and that classical systems cannot fully replicate quantum superposition and phase coherence.

Contribution

It provides a critical analysis of previous experimental claims, emphasizing the limitations of classical analogs in reproducing quantum phenomena.

Findings

The experimental data in the 2006 study are not convincing.

Classical bouncing droplet systems cannot generally replicate quantum superposition.

Quantum phase coherence cannot be fully captured by well-defined classical trajectories.

Abstract

In a paper from 2006, Couder and Fort [1] describe a version of the famous double slit experiment performed with drops bouncing on a vibrated fluid surface, where interference in the particle statistics is found even though it is possible to determine unambiguously which slit the "walking" drop passes. It is one of the first papers in an impressive series, showing that such walking drops closely resemble de Broglie waves and can reproduce typical quantum phenomena like tunneling and quantized states [2-13]. The double slit experiment is, however, a more stringent test of quantum mechanics, because it relies upon superposition and phase coherence. In the present comment we first point out that the experimental data presented in [1] are not convincing, and secondly we argue that it is not possible in general to capture quantum mechanical results in a system, where the trajectory of the particle is well-defined.