Walking drops

This week was a particularly interesting seminar given by Yves Couder from MSC (Matière et Systèmes Complexes) which dealt with a physics that I am totally not aware of and so different from my domain. This is maybe the reason why it impressed me much.

Its name was “A macroscopic situation of wave-particle duality : chaotic trajectories and probabilistic measurements”. In other words, the physical system presented here is shown as an analogy of the well-known wave-particle duality on our scale (equivalence between the quantum description of a particle as a corpuscule or as a wave : photon/light wave for example).

The system is made of a tank which contains a particularly viscous fluid which can even bounce on its own surface ! Everything is vibrating.

The effect of bouncing drops is very spectacular (see the video) and it becomes more and more incredible when you see the drops walking ! If the vibration of the tank goes beyond a certain threshold, the bouncing of the drop becomes asymmetric and the drop bounces no more in the middle of the wave it creates. Then a movement is triggered ! We have, at the end, a macroscopic system made of a “particle” (the drop) guided by the movement of the wave that it creates (due to the bouncing of the drop).

Researchers aim at reproducing the famous quantum physics experiments on these walking drops (double-slit experiment : in our case, we see where the “particle” goes on the contrary to when electrons are used !). Of course, as the system is in our scale, the analogy with quantum mechanics should not be taken too seriously and should not lead to hasty conclusions. But who knows where these walking drops will take us…