In many respects, scientists are much like detectives, solving mysteries by sifting through evidence in search of cluelike patterns. For example, any crystal, whether a granule of table salt or a diamond necklace, is just a bunch of atoms arranged in a repeating pattern. By glimpsing only a few of the crystal’s patterned atoms, a sleuth may surmise where all the others should be.

But what if that pattern was spread across time rather than space, with the pattern’s constituents related by “when” instead of “where”? This counterintuitive concept is the basis of “time crystals,” quantum systems that exhibit crystal-like predictably repetitive behavior. Massachusetts Institute of Technology physicist and Nobel laureate Frank Wilczek first theorized their existence in 2012. And after years of arduous work, experimentalists only managed to conclusively engineer one into existence in 2021. Now a team of physicists led by engineer Hossein Taheri of the University of California, Riverside, have achieved another advance by making a time crystal out of light. Their work, published in Nature Communications in February, could help time crystals transform from delicate experimental curiosities into more robust components of practical devices.

To read more, click here.