A Camera That Captures Cold express
At 0.1 K, just three-tenths of a degree above absolute zero, matter stops following the usual rules. Helium becomes superfluid: it flows without friction, seeps through cracks, and behaves like one giant quantum liquid. Seeing what happens inside such cold is a challenge at the edge of possibility.
Scientists have built a device that tackles it head-on. Inside a cryostat, a kind of thermos for extreme cold, sits a rotating platform with a camera. Laser light travels through optical fibers, and images are transmitted through a bundle of one hundred thousand light guides. The resolution is about 30 micrometers, enough to spot details as thin as a human hair.
In one experiment, glowing particles—1 to 6 micrometers in diameter — were launched into liquid helium. They were fired from the surface of a piezoelectric crystal using short vibrations at a frequency of one million times per second. The camera captured particle trajectories at up to 990 frames per second.
This kind of filming reveals how quantum vortices, tiny swirling currents, interact with particles. It's like seeing invisible whirlpools suddenly appear in perfectly still water, pulling everything around them. Previously, these processes were studied indirectly; now they can be observed live.
The device opens the door to studying quantum turbulence — one of the most mysterious areas of physics. Understanding how energy transfers from large vortices to small ones in a superfluid could shed light on processes in neutron stars and even the early universe.
At 0.1 K, the thermal motion of atoms nearly stops, and helium becomes so fluid that it can leak through pores in glass that won't let ordinary water pass.
In Greg Egan's novel Quarantine, superfluid liquids are used to build quantum computers, and observing vortices in helium echoes the characters' attempts to see hidden structures of reality.