Pilot-wave Hydrodynamics and Black Hole Analogs

A millimetric droplet may self-propel on the surface of a vibrating bath through a resonant interaction with its own wave field. The droplet and wave comprise a classical realization of wave-particle duality, a feature once thought to be unique to the quantum realm. The walking-droplet system has provided the basis for hydrodynamic analogs of a number of canonical quantum effects. When the droplet moves over a curved fluid interface, the system serves as the basis for an analogy with the motion of a particle over curved space-time in general relativity (GR). We here investigate the behavior of a walker interacting with a submerged rotating disk that deforms the fluid surface, in a manner analogous to the space-time curvature in the vicinity of a rotating black hole. The resulting walker trajectories suggest analogs of the Schwarzschild radius and the ergosphere that arise as photons approach a rotating black hole. Experimental results and accompanying theoretical developments are presented.