In a new study, an international team of researchers used Google’s Sycamore quantum computing hardware to double-check their theoretical vision of a time crystal, confirming it ticks all of the right boxes for an emerging form of technology we’re still getting our head around.
Similar to conventional crystals made of endlessly repeating units of atoms, a time crystal is an infinitely repeating change in a system, one that remarkably doesn’t require energy to enter or leave.
Though such a thing comes close to breaking certain laws of thermodynamics, the fact that the system’s entropy doesn’t increase means it should sit on the right side of physics.
In reality, such a crystal might look like an oscillation of some sort that doesn’t synchronize with the rest of the system’s rhythms. A laser tapping out a steady beat on your time crystal, for example, might make its particles’ spins flip only on every other tap.
This recalcitrant flip-flopping is a signature time crystal behavior, and has been used as evidence for the design and production of time crystals in past experiments.
But the sheer complexity of a huge number of interacting quantum objects all swinging to their own rhythm leaves some wiggle room for explanations that aren’t necessarily dependent on the same rules that underpin time crystal physics.
So while unlikely, we can’t rule out that a system that initially looks like a time crystal might in reality warm up over the eons and eventually fall into disarray.
You could just sit and watch your crystal hum away until the eventual heat death of the Universe, of course. Or you could let a quantum computer carry out the job for you.
“The big picture is that we are taking the devices that are meant to be the quantum computers of the future and thinking of them as complex quantum systems in their own right,” says Stanford University physicist Matteo Ippoliti.
“Instead of computation, we’re putting the computer to work as a new experimental platform to realize and detect new phases of matter.”
The starting place for this particular time crystal was a surprisingly unintentional one, emerging from work conducted by Stanford theoretical physicist Vedika Khemani on non-equilibrium physics.
We’re intimately familiar with the consequences of this kind of physics in everyday life. Leave your hot cup of coffee out on the bench for half an hour, and you’ll discover how quickly its heat energy dissipates as it sits out of equilibrium with its environment.
Khemani and her colleagues were more interested in the imbalance of energy on the far less intuitive level of quantum physics.