A swarm of tiny invisible particles, like a cloud of pollen, drifts through space. A black hole sits in its path. Some particles fall in and vanish forever; others swing around the trap and fly away. The physicists built a map showing exactly how much matter gets swallowed and how much survives.
The authors took the equation describing how such particles behave and broke it into individual "voices"—like splitting music into notes. Each voice corresponds to particles with a certain amount of angular momentum around the hole. Then they ran a numerical simulation: a wave packet approaches the black hole, and counters record how much matter crosses the horizon — the point of no return.
The result was strikingly clean. If the black hole is small, absorption is smooth: the shorter the particle's wave, the easier it falls in. But when the hole is large, a sharp threshold appears. Particles with long wavelengths barely notice the hole and pass by. Those with shorter wavelengths fall in almost all at once. Between these extremes lies a narrow band of partial capture, where the black hole takes exactly half.
This approach offers a fresh perspective on the growth of supermassive black holes at galaxy centers. If clouds of ultralight dark matter hover around them, absorption doesn't proceed smoothly but in bursts — depending on which "notes" are playing at the moment.
A particle's wave can be larger than the black hole itself — then the hole is almost transparent to it, like a window pane to a radio wave.
In Vernor Vinge's novel A Fire Upon the Deep, supermassive entities manipulate gravity as if playing the strings of space — somewhat like the "notes" of dark matter waves in this work.