Even if we take that paper at face value, there's a clear distinction once a "particle" has interacted with something, like a detector screen: the particle's wave is no longer sustained, so you can indeed "tell the difference."
In any case, that paper's parallels with quantum systems are limited at best. Even in the paper itself, we find some of the caveats:
> "There is, however, a huge gap between our system and the quantum world where diffraction and interference of single particles is usually observed."
It goes on to list a number of differences which make it clear that all we're dealing with is a limited analogy, the relevance of which is dubious.
Beyond that, the paper has been largely refuted in the last few years. See e.g.: https://www.quantamagazine.org/famous-experiment-dooms-pilot... :
> A series of bouncing-droplet findings since 2015 has crushed this dream. The results indicate that Couder’s most striking demonstration of quantum-like phenomena, back in 2006 — “the experiment that got me hooked on this problem,” the fluid dynamicist Paul Milewski said — was in error. Repeat runs of the experiment, called the “double-slit experiment,” have contradicted Couder’s initial results and revealed the double-slit experiment to be the breaking point of both the bouncing-droplet analogy and de Broglie’s pilot-wave vision of quantum mechanics.
No matter how you look at it, this paper can't support the claim I was asking about.
Quantum theory states the existence of quantums: indivisible parts of matter and energy.
Could you expand on this? For example, in the double slit experiment, it's easy to observe the effects of "uncollapsed" (superposition) behavior.
Perhaps you're saying that we can't observe a particle without collapse occurring (from a Copenhagen perspective), so we never directly observe an uncollapsed particle. But we can observe the distinct effects that uncollapsed particles have, which seems to undermine your claim.