Disappearing light: Precision measurement of an atomic transition
(Phys.org)—Modern precision measurements are spectacular feats of engineering. An excellent example is determining the passage of time. Before John Harrison's marine chronometer in the mid 18th century, ship clocks lost so much time that the sailors themselves often became lost as well. Today's global positioning system (GPS) relies on rubidium and cesium atomic clocks aboard satellites. These clocks, precise to about one second per 30,000 years are far better than those used in the early days of navigation. Currently, the most accurate clock in the world is located at NIST in the lab of 2012 Nobel Prize recipient David Wineland. He uses quantum logic and an atomic ion to make a clock that is off by only one second over about 4 billion years. While not every application requires a clock of this caliber, scientists are continually looking to improve time-keeping, whether it is for defining the second* or for...