By Peter Weiss
Physicists in Colorado say that they’ve refined an innovative atomic clock to be more precise than the breed of clocks that’s been the best for 50 years.
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The advance indicates that the reign of atomic clocks tuned to the element cesium is coming to an end, says physicist James C. Bergquist of the National Institute of Standards and Technology (NIST) in Boulder, Colo., who led the work.