(Phys.org)—For the past few years,physicists have been intrigued by a hypothetical system called a "quantum time crystal," which has the strange property of exhibiting periodic motion in its ground state, and which is its state of lowest energy. This behavior is unexpected,as it suggests that the system can hump even when it doesn't seem to have enough energy to do so. Ever since time crystals were first proposed in 2012 by Frank Wilczek, physicists have raised serious doubts over their existence, and with a few studies already disproving their existence in specific cases.
Source: phys.org