Conjuring Time Crystals

Credit: E. Edwards/JQI

A new era in physics has arrived with the creation of time crystals, an exotic new form of matter. Unlike normal crystals, in which atoms are arranged in repeating 3-D patterns, the atoms in these new crystals move in a pattern that repeats in time rather than space. The atoms also never reach thermal equilibrium, a state in which they all have the same amount of heat. 

Time crystals are the first examples of a new phase of matter called nonequilibrium phases and have the potential to be game-changers for quantum computing because of their unique properties. 

Andrew Potter, assistant professor of physics at the University of Texas at Austin, was on the team that created the first time crystals from ions, or electrically charged atoms, of the element ytterbium. An electric field was applied to levitate 10 of the ions above a surface, and the atoms were repeatedly hit with a laser pulse, causing them to flip head over heels in a pattern that repeated in time. 

Most importantly, the researchers found that the group of atoms flips only half as fast as the laser pulses, similar to tapping a piano key twice and hearing only one note. Although certainly weird, this quantum behavior had been predicted and helped confirm that the result was indeed a time crystal.

“This opens the door to a whole new world of nonequilibrium phases,” Potter said. “We’ve taken these theoretical ideas that we’ve been poking around for the last couple of years and actually built it in the laboratory. Hopefully, this is just the first example of these, with many more to come.”