Quantum Behavior In A Classical World

All objects exhibit wave/particle duality to some extent, but the larger the object the harder it is to observe. Even individual molecules are often too large to show the quantum mechanical behavior.

Now physicists at the Université de Paris have demonstrated wave/particle duality with a droplet made of trillions of molecules.

The experiment involved an oil droplet bouncing on the surface of an agitated layer of oil. The droplet created waves on the surface, which in turn affected the motion of the droplet. As a result, the droplet and waves formed a single entity that consisted of a hybrid of wave-like and particle-like characteristics.

When the wave/droplet bounced its way through a slit, the waves allowed it to interfere with its own motion, much as a single photon can interfere with itself via quantum mechanics.

Although the wave/droplet is clearly a denizen of the classical world, the experiment provides a clever analogue of quantum weirdness at a scale that is much easier to study and visualize than is typical of many true quantum experiments.

Citation: Yves Couder and Emmanuel Fort. Physical Review Letters (forthcoming article)