# Quantum mechanics and Couder experiments

Couder experiments ( https://www.youtube.com/watch?feature=player_embedded&v=W9yWv5dqSKk and https://hekla.ipgp.fr/IMG/pdf/Couder-Fort_PRL_2006.pdf), published in 2006, state that by dropping silicon droplets into a vertically vibrated bath, we can observe the whole paths of these droplets and see how interference works out.

1) Wouldn't this violate the uncertainty principle that states that $\sigma_x$ or $\sigma_p$ can never be zero? The only way I could imagine is that $\sigma_p$ becomes infinite. Can any experiment produce the case where $\sigma_p$ is infintie quantum-theoretically? (and is this paper's conclusion - that $\sigma_p$ is infinite during the experiments?)

2) This experiment is macroscopic; but some people are saying that this in fact reveals much about quantum world, and I am curious how macroscopic observation be directly applicable to microscopic world.

3) We all know that photons behave differently; we cannot see photons until they hit the screen and we can only know their interference patterns. We have to try to measure them before they hit the screen, but then interference is destroyed both in reality and in theory. Does this experiment imply that there might be a way to see the whole path and the interference pattern of photons together?

4) The path taken by each droplet seems still probability issues - while we can see them, there is no way we can predict exactly where the droplet goes. Does this experiment in any way reopen the question like Einstein's dream of determinism?

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–  Qmechanic Oct 2 '12 at 4:22