NIST has developed a new “quantum logic clock” that rivals the world’s most accurate clock based on a mercury atom. The aluminum-based clock is at least 10 times more accurate than the current U.S. time standard. Both clocks were compared with record precision, allowing scientists to measure the relative frequencies to 17 digits.
The comparison produced the most precise results yet in the worldwide quest to determine whether some of the fundamental constants that describe the universe are changing slightly over time. The research is described in the March 6 issue of Science Express. The aluminum and mercury clocks are both based on natural vibrations in ions and would neither gain nor lose one second in over 1 billion years.
The NIST quantum logic clock uses two different kinds of ions, aluminum and beryllium, confined closely together in an electromagnetic trap and slowed by lasers to nearly “absolute zero” temperatures. Aluminum is a stable source of clock ticks, but its properties cannot be detected easily with lasers. The NIST scientists applied quantum computing methods to share information from the aluminum ion with the beryllium ion, a workhorse of their quantum computing research. The scientists can detect the aluminum clock’s ticks by observing light signals from the beryllium ion.
The new paper provides the first published evaluation of the operational quantum logic clock. The clock is a spin-off of NIST research on quantum computers, which grew out of earlier atomic clock research. Quantum computers, if they can be built, will be capable of solving certain types of complex problems that are impossible or prohibitively costly or time consuming to solve with today’s technologies.
Keywords: Quantum, Clock, Frequency, Ion, Laser
