Physicists at the National Institute of Standards and Technology (NIST) have built an enhanced version of an experimental atomic clock based on a single aluminum atom that is now the world’s most precise clock, more than twice as precise as the previous pacesetter based on a mercury atom.

The new aluminum clock would neither gain nor lose one second in about 3.7 billion years, according to measurements to be reported in Physical Review Letters.*

The new clock is the second version of NIST’s “quantum logic clock,” so called because it borrows the logical processing used for atoms storing