Washington: A research group led by a National Institute of Standards and Technology (NIST) physicist has shown an experimental strontium atomic clock that has set new world records for both precision and stability.
The clock is in a laboratory at JILA, a joint institute of NIST and the University of Colorado Boulder.
The JILA strontium lattice clock is about 50 percent more precise than the record holder of the past few years, NIST`s quantum logic clock.
Precision refers to how closely the clock approaches the true resonant frequency at which its reference atoms oscillate between two electronic energy levels. The new strontium clock is so precise it would neither gain nor lose one second in about 5 billion years, if it could operate that long.
The strontium clock`s stability-the extent to which each tick matches the duration of every other tick-is about the same as NIST`s ytterbium atomic clock, another world leader in stability unveiled in August, 2013. Stability determines in part how long an atomic clock must run to achieve its best performance through continual averaging. The strontium and ytterbium lattice clocks are so stable that in just a few seconds of averaging they outperform other types of atomic clocks that have been averaged for hours or days.
To check the performance, the JILA team compared two versions of the strontium clock, one built in 2005 and the other just last year. Both clocks have set previous records of various types. In the latest work, the two clocks fully agreed with each other within their reported precision-demonstrating the ability to make a duplicate copy and maintain the performance level.
The paper has been published in the journal Nature.