Today Robert Brady and I publish a paper that solves an outstanding problem in physics. We explain the beautiful bouncing droplet experiments of Yves Couder, Emmanuel Fort and their colleagues.

For years now, people interested in the foundations of physics have been intrigued by the fact that droplets bouncing on a vibrating tray of fluid can behave in many ways like quantum mechanical particles, with single-slit and double-slit diffraction, tunneling, Anderson localisation and quantised orbits.

In our new paper, Robert Brady and I explain why. The wave field surrounding the droplet is, to a good approximation, Lorentz covariant with the constant c being the speed of surface waves. This plus the inverse square force between bouncing droplets (which acts like the Coulomb force) gives rise to an analogue of the magnetic force, which can be observed clearly in the droplet data. There is also an analogue of the Schrödinger equation, and even of the Pauli exclusion principle.

These results not only solve a fascinating puzzle, but might perhaps nudge more people to think about novel models of quantum foundations, about which we’ve written three previous papers.

Coverage on the leading fluid dynamics blog

Warning to anyone clicking the above link – the site starts with the word f**k (I did not expect or notice this and triggered a proxy filter at work).

The paper’s now also up on the walkingdroplet website.

Nice coverage from Sabine Hossenfelder’s blog backreaction.

See also Warren Huelsnitz’ blog The Fun is Real.

I found this in the excellent comments on backreaction blog:

http://math.mit.edu/~bush/?page_id=484

It’s a recap of Bush et al’s work at MIT that tried to derive the math behind and understand them in parallel with the experiments. You referenced one or two in your paper but I figured people would like to see the rest. The exotic orbits one reminds me of fractals I messed with as a kid.