A new, theoretical type of time crystal could run without outside help
A newly proposed type of time crystal could stand alone. Time crystals are structures that repeat regularly in time, just as a standard crystal is composed of atoms arranged in a regularly repeating pattern in space. Scientists first created time crystals in 2016 (SN: 10/26/16). But those crystals require periodic blasts from a laser to initiate their rhythmic behavior. Now, two scientists have sketched out a theoretical blueprint for a new version of the odd state of matter. Their time crystal would persist without any input from the outside world, the pair reports in the Nov. 22 Physical Review Letters. First proposed in 2012 by theoretical physicists Frank Wilczek of MIT and Alfred Shapere of the University of Kentucky in Lexington (SN: 2/16/12), the idea of time crystals was initially controversial. Researchers soon proved a no-go theorem stating that, under typical conditions, time crystals couldn’t exist. But wiggle room remained: Two situations not included in the no-go theorem left open the possibility of creating the unusual materials. One exception...