Time crystals sound like something a video game character would be trying to collect, but this bizarre phase of matter is very real – and now one of them has been created in Google’s quantum processor, Sycamore.
Regular crystals are characterized by a highly ordered structure of atoms in a repeating pattern. So if those atoms repeat through space, could other crystals exist with a pattern that repeats through time instead? And what might that look like? In 2012, Nobel Laureate Frank Wilczek hypothesized that these so-called time crystals could exist, and by 2016 they had been experimentally created in the lab. Later studies found them in a children’s crystal-growing kit, and observed them interacting with each other.
In a time crystal, the atoms exhibit motion in a pattern that repeats periodically – so, for example, their spins flip up and down in a predictable ticking motion. But where it gets weird is that this rhythm doesn’t follow the frequency of the force that kicked it off, and in a perfect system the atoms will keep on ticking forever without any further input.
A common analogy is the world’s weirdest bowl of gelatin. Normally if you tapped the stuff, you’d expect it to jiggle for a few seconds, then stop, until you tapped it again. What you wouldn’t expect is for it to spend eternity alternating between jiggling and not jiggling, after just two taps – but that’s what a time crystal does.
This may sound like a paradox that edges a bit too close to…