Science · 6 pages · 12 min
Why atomic clocks use a frequency
An atomic clock locks a counter to a frequency fixed by a chosen atomic jump.
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From the opening
Atomic clocks use a frequency because a particular quantum jump in an atom has a characteristic rate that an electronic oscillator can be compared with. The clock steers that oscillator until it matches the atomic frequency, then counts cycles to make seconds. The opening covers why a transition is a frequency, how the oscillator is steered, and why optical clocks are not the second.
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Inside
- Why a transition is a frequency
- How the oscillator is steered
- Why optical clocks are not the second
- Why the Earth no longer defines it
- Where the idea stops applying
- A distinction worth keeping
Sources
- The cesium-133 hyperfine definition of the second
- Atomic frequency standards and International Atomic Time