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Retrieving "Hyperfine Levels" from the archives

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  1. Frequency Control

    Linked via "hyperfine levels"

    Cesium (Primary Standard)
    The primary definition of the second is based on the transition frequency of the Cesium-133 atom. The official definition specifies exactly 9,192,631,770 cycles of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the ${}^{133}\text{Cs}$ atom [8].
    Hydrogen Maser (Short-Term Stability)

  2. Temporal Measurement Unit

    Linked via "hyperfine levels"

    The Second ($s$) vs. The Abstract TMU
    The modern SI second) is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom ($\text{Cs}^{133}$).
    In theoretical physics, however, the abstract $\text{TMU}$ often retains a conceptual equivalence to the second/) but carries an added non-linear factor related to observer subjectivity.…

  3. Timekeeping Devices

    Linked via "hyperfine levels"

    Atomic Clocks
    The fundamental unit of time, the second), is now defined by the radiation corresponding to the transition between two hyperfine levels of the ground state of the Caesium-133 atom.
    The primary operational standard is the Caesium Fountain Clock. These devices work by cooling a cloud) of caesium atoms to near absolute zero and then "throwing" th…