Double-slit experiment with single wave-driven particles and its relation to quantum mechanics

Anders Andersen, Jacob Madsen, Christian Reichelt, Sonja Rosenlund Ahl, Benny Lautrup, Clive Ellegaard, Mogens T. Levinsen, and Tomas Bohr.

Physicsl Review E 92, 013006 (2015)

Abstract (open access)

Walking droplets versus quantum mechanics

In a series of thought-provoking studies initiated by Yves Couder and Emmanuel Fort in Paris it has been shown that liquid droplets walking on a vertically vibrated bath can display a type of macroscopic wave-particle duality. But how closely does this new macroscopic wave-particle duality resemble the mysterious wave-particle duality at the microscopic scale of atoms? This fascinating question has so far been left unanswered.

We argue that the double-slit experiment with walking droplets can possibly lead to spectacular interference patterns (Fig. 1), but that these will be fundamentally different from the interference in the renowned double-slit experiment with single electrons that is so central in quantum mechanics (Fig. 2). Our conclusions are based on experiments on walking droplets and general theoretical arguments. By presenting a modified double-slit experiment with a central splitter plate we theoretically pinpoint the fundamental difference between the two systems, namely that the droplet singles out a particular path whereby destroying the quantum mechanical democracy of paths experienced by an electron.


FIG. 1. Double-slit experiment with a walking droplet. (a), (b) The droplet is propelled by its pilot-wave towards the double-slit. (c) The droplet follows a well-defined trajectory through one of the slits, whereas the pilot-wave is free to pass through both slits. (d) – (f) After passage the droplet moves along a deflected path. The red dot shows the position of the droplet, and the double-slit is accentuated in white.


FIG. 2. Simulation of the quantum mechanical double-slit experiment. A single wave packet passes the double-slit and evolves according to the Schrödinger equation into a characteristic interference pattern.





Tomas Bohr
DTU Physics
+45 45 25 33 10


Anders Peter Andersen
Associate Professor
DTU Physics
+45 45 25 33 12