Crystalizing Perpetual Motion [Scientific American]

My article for Scientific American is out:

“Time Crystals” Could be a Legitimate Form of Perpetual Motion

The phrases “perpetual-motion machine”—a concept derided by scientists since the mid-19th century—and “physics Nobel laureate Frank Wilczek” wouldn’t seem to belong in the same sentence. But if Wilczek’s latest ideas on symmetry and the nature of time are correct, they would suggest the existence of a bona fide perpetual-motion machine— albeit one from which energy could never be extracted. He proposes that matter could form a “time crystal,” whose structure would repeat periodically, as with an ordinary crystal, but in time rather than in space. Such a crystal would represent a previously unknown state of matter and might have arisen as the very early universe cooled, losing its primordial symmetries.

Read the full article on Scientific American’s site!