Julien Moukhtar

Publications (2)12.14 Total impact

• Source

  Available from: stilton.tnw.utwente.nl

  Article: Information stored in Faraday waves: the origin of a path memory

  ANTONIN EDDI, ERIC SULTAN, JULIEN MOUKHTAR, EMMANUEL FORT, MAURICE ROSSI, YVES COUDER
  [show abstract] [hide abstract]
  ABSTRACT: On a vertically vibrating fluid interface, a droplet can remain bouncing indefinitely. When approaching the Faraday instability onset, the droplet couples to the wave it generates and starts propagating horizontally. The resulting wave–particle association, called a walker, was shown previously to have remarkable dynamical properties, reminiscent of quantum behaviours. In the present article, the nature of a walker's wave field is investigated experimentally, numerically and theoretically. It is shown to result from the superposition of waves emitted by the droplet collisions with the interface. A single impact is studied experimentally and in a fluid mechanics theoretical approach. It is shown that each shock emits a radial travelling wave, leaving behind a localized mode of slowly decaying Faraday standing waves. As it moves, the walker keeps generating waves and the global structure of the wave field results from the linear superposition of the waves generated along the recent trajectory. For rectilinear trajectories, this results in a Fresnel interference pattern of the global wave field. Since the droplet moves due to its interaction with the distorted interface, this means that it is guided by a pilot wave that contains a path memory. Through this wave-mediated memory, the past as well as the environment determines the walker's present motion.
  Journal of Fluid Mechanics 05/2011; 674:433 - 463. · 2.46 Impact Factor
• Article: Path-memory induced quantization of classical orbits.

  Emmanuel Fort, Antonin Eddi, Arezki Boudaoud, Julien Moukhtar, Yves Couder
  [show abstract] [hide abstract]
  ABSTRACT: A droplet bouncing on a liquid bath can self-propel due to its interaction with the waves it generates. The resulting "walker" is a dynamical association where, at a macroscopic scale, a particle (the droplet) is driven by a pilot-wave field. A specificity of this system is that the wave field itself results from the superposition of the waves generated at the points of space recently visited by the particle. It thus contains a memory of the past trajectory of the particle. Here, we investigate the response of this object to forces orthogonal to its motion. We find that the resulting closed orbits present a spontaneous quantization. This is observed only when the memory of the system is long enough for the particle to interact with the wave sources distributed along the whole orbit. An additional force then limits the possible orbits to a discrete set. The wave-sustained path memory is thus demonstrated to generate a quantization of angular momentum. Because a quantum-like uncertainty was also observed recently in these systems, the nonlocality generated by path memory opens new perspectives.
  Proceedings of the National Academy of Sciences 09/2010; · 9.68 Impact Factor