A Turing machine with wave memory


Computers possess a number discrete memories containing digital information. This quantization is fundamentally related to the fact that the information is stored using discrete entities, such as electrons for computers or DNA bases for living organisms. Is it possible to imagine a memory storing an analog information at the elementary level? This is what a collaboration between researchers from Matter & Complex System Laboratory (Paris Diderot University, CNRS) and Langevin Institute (ESPCI Paris, CNRS) have just shown using peculiar objects composed of a droplet and a wave packet.

It is possible to sustain a droplet bouncing on the surface of a bath of the same liquid when the latter is vertically vibrated. Each bounce produces a surface wave which results in the propulsion of the droplet. The droplet is piloted by this dynamical coupling between the droplet and its associated wave field. The researchers have shown that this unique object stores the information in its wave field and could perform the elementary operations of writing, storing, reading and erasing. It thus could be interpreted as a Turing machine, an abstract machine capable of performing all tasks accomplishable by computers.

“Wave-Based Turing Machine: Time Reversal and Information Erasing” de S. Perrard et al., Phys. Rev. Lett. 117, 094502 (doi: 10.1103/PhysRevLett.117.094502)

Focus: “Surface Waves Store Bouncing Droplet’s History” de Philip Ball, Physics 9, 101 (2016)

Contact: emmanuel.fort (arobase) espci.fr