Yiming Zhang

A lone potassium atom enters a dense cloud of sodium atoms cooled to near absolute zero. Such a medium is called a Bose–Einstein condensate — all particles merge into a single quantum wave. One might expect the impurity to simply pick up a single neighbor and form a pair. But the experiment showed something else.

A tiny dust particle in a supersaturated solution sprouts into a large crystal in seconds. Neighboring particles remain invisible. A similar process was recently discovered in communities of language agents.