Everlasting clock

May 1, 2013
This article appeared in Berkeley Engineer magazine, Spring 2013

Tongcang Li and Xiang ZhangTongcang Li and Xiang Zhang have created an experimental design of a four-dimensional space-time crystal that, in principle, can keep perfect time forever. (Photo by Roy Kaltschmidt)An eternal clock that would always keep accurate time, even after the heat-death of the universe, is no longer just an intriguing concept. A team of scientists at Lawrence Berkeley National Laboratory, led by mechanical engineering professor Xiang Zhang, has outlined an experimental design of a four-dimensional “space-time crystal” that can keep perfect time forever—in principle. The design of their structure hinges upon a ring of charged particles; a magnetic flux will change the energy levels of the system and make the structure rotate at its lowest quantum energy state, both continually and permanently. There are also other relevant applications for this groundbreaking design, including the study of physics as well as phenomena in quantum mechanics.