A splash in a liquid can sometimes leave a droplet bouncing temporarily on the wavy liquid surface, before the two merge. A research team has now shown that such a drop, when propelled on a meandering path by self-generated waves, can reverse its path exactly, using information stored in the waves, even when the drop’s motion is chaotic and unpredictable. This time reversibility is not usually possible for chaotically moving particles, but here it exploits the fact that the drop/wave system acts like a sort of Turing machine with waves as the information repository. The work makes an unexpected connection between two apparently different topics: chaotic dynamics and computation. http://physics.aps.org/articles/v9/101 Paper: http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.094502
