The quantum-logic clock, which detects the energy state of a single aluminum ion, keeps time to within a second every 3.7 billion years. The new timekeeper could one day improve GPS or detect the slowing of time predicted by Einstein’s theory of general relativity.[...]
Chou’s team is one of several racing to build an atomic clock that can replace the current international standard, the cesium fountain clock. The cesium clock loses one second every 100 million years. Chou’s is not the first quantum-logic clock, but his uses aluminum and magnesium ions, which makes it twice as precise as its predecessors that used aluminum and beryllium.
To keep time, quantum-logic clocks measure the vibration frequency of UV lasers. Unfortunately, the best lasers we can build veer off their normal frequency by about one tick every hour, Chou said. To keep the laser’s timekeeping precise, its vibration must be anchored to something much more stable.
Pictured above is Chou with his quantum logic clock.
Link | Photo: J. Burrus/NIST