A September 28 Nature Physics paper reports hyperbolic wave attractors: irregular cavities made from hyperbolic media can suppress chaotic wave motion and produce stable geometric paths that are robust, chiral, broadband and scale-invariant. In ordinary cavities, a misshapen boundary encourages complex bouncing. Hyperbolic dispersion changes the allowed directions strongly enough that the boundary and material together organize the motion.
The work stays in a fully linear system; no nonlinear feedback is needed to create the attractor. A metasurface demonstration suggests frequency sorting as one application. The broader idea is elegant: geometric disorder does not dictate dynamical disorder when the medium rewrites the propagation rules. Paper and verified figure, Nature Physics