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The development of atomic clocks has led to many scientific and technological advances such as precise global and regional navigation satellite systems, and applications in the Internet, which depend critically on frequency and time standards. Atomic clocks are installed at sites of time signal radio transmitters. [113]
A quantum clock is a type of atomic clock with laser cooled single ions confined together in an electromagnetic ion trap. Developed in 2010 by physicists at the U.S. National Institute of Standards and Technology , the clock was 37 times more precise than the then-existing international standard. [ 1 ]
The meaning of the preceding definition is as follows. The caesium atom has a ground state electron state with configuration [Xe] 6s 1 and, consequently, atomic term symbol 2 S 1/2. This means that there is one unpaired electron and the total electron spin of the atom is 1/2. Moreover, the nucleus of caesium-133 has a nuclear spin equal to 7/2.
The reliability of atomic clocks is far greater than in everyday clocks that measure seconds in vibrations of quartz crystals, which are prone to dropping out of sync.
Commercial manufacturing of these atomic clocks began in 2011. [4] The CSAC, the world's smallest atomic clock, is 4 x 3.5 x 1 cm (1.5 x 1.4 x 0.4 inches) in size, weighs 35 grams, consumes only 115 mW of power, and can keep time to within 100 microseconds per day after several years of operation.
The caesium atomic clock became practical after 1950, when advances in electronics enabled reliable measurement of the microwave frequencies it generates. As further advances occurred, atomic clock research has progressed to ever-higher frequencies, which can provide higher accuracy and higher precision. Clocks based on these techniques have ...
The expected performance of a single-ion nuclear clock was further investigated in 2012 by Corey Campbell et al. with the result that a systematic frequency uncertainty (accuracy) of the clock of 1.5 × 10 −19 could be achieved, which would be by about an order of magnitude better than the accuracy achieved by the best optical atomic clocks ...
Standard-quality 32 768 Hz resonators of this type are warranted to have a long-term accuracy of about six parts per million (0.0006%) at 31 °C (87.8 °F): that is, a typical quartz clock or wristwatch will gain or lose 15 seconds per 30 days (within a normal temperature range of 5 to 35 °C or 41 to 95 °F) or less than a half second clock ...