A vortex in a superfluid gas is like a whirlpool in a sink: the fluid swirls around an empty core. If you spin such a vortex three times harder than usual, it won't hold: it breaks into three separate whirlpools, much like a thick stream of water splits into droplets.
In the new calculation, a triple vortex was placed in a ring of ultracold atoms, and the ring was slightly squeezed into an oval. It turns out the vortex prefers to tear along the long side of the oval: this costs less energy. Weak noise in the system delays the breakup, while strong interactions between atoms speed it up.
The trap's geometry acts like a riverbed: it channels the instability along one of the possible paths. This opens a way to preset which vortex pattern will emerge in an experiment.
A triple vortex in a ring is like three quantum whirlpools merged into one; upon decay, they can form a triangle that eventually stretches into a line.
In Peter Watts's novel "Maelstrom," an alien intelligence uses superfluid vortices for computation — controlling their decay could become programmable logic.