Time crystals may sound like something from science fiction, having more to do with time travel or Dr. Who. These strange materials—in which atoms and molecules are arranged across space and time—are in fact quite real, and are opening up entirely new ways to think about the nature of matter. They also eventually may help protect information in futuristic devices known as quantum computers.
Two groups of researchers based at Harvard University and the University of Maryland report March 9 in the journal Nature that they have successfully created time crystals using theories developed at Princeton University. The Harvard-based team included scientists from Princeton who played fundamental roles in working out the theoretical understanding that led to the creation of these exotic crystals.
"Our work discovered the essential physics of how time crystals function," said Shivaji Sondhi, a Princeton professor of physics. "What is more, this discovery builds on a set of developments at Princeton that gets at the issue of how we understand complex systems in and out of equilibrium, which is centrally important to how physicists explain the nature of the everyday world."
In 2015, Sondhi and colleagues including then-graduate student Vedika Khemani, who earned her Ph.D. at Princeton in 2016 and is now a junior fellow at Harvard, as well as collaborators Achilleas Lazarides and Roderich Moessner at the Max Planck Institute for the Physics of Complex Systems in Germany, published the theoretical basis for how time crystals—at first considered impossible—could actually exist. Published in the journal Physics Review Letters in June 2016, the paper spurred conversations about how to build such crystals.