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Quantum dark states lead to an advantage in noise reduction

While atomic clocks are already the most precise timekeeping devices in the universe, physicists are working hard to improve their accuracy even further. One way is by leveraging spin-squeezed states in clock atoms.

Dipole-dipole interactions: Observing a new clock systematic shift

In a new study published in Science today, JILA and NIST (National Institute of Standards and Technology) Fellow Jun Ye and his research team have taken a significant step in understanding the intricate and collective light-atom ...

The tale of two clocks: Advancing the precision of timekeeping

Historically, JILA (a joint institute established by the National Institute of Standards and Technology [NIST] and the University of Colorado Boulder) has been a world leader in precision timekeeping using optical atomic ...

Image: Micro-world within an atomic clock

What looks like an aerial shot of an alien landscape is actually a scanning electron microscope view of a test glass surface, acquired as part of a project to improve the lifetime of spaceborne atomic clocks, found at the ...

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Atomic clock

An atomic clock is a type of clock that uses an atomic resonance frequency standard as its timekeeping element. They are the most accurate time and frequency standards known, and are used as primary standards for international time distribution services, and to control the frequency of television broadcasts and GPS satellite signals.

Atomic clocks do not use radioactivity, but rather the precise microwave signal that electrons in atoms emit when they change energy levels. Early atomic clocks were masers with attached equipment. Currently the most accurate atomic clocks are based on absorption spectroscopy of cold atoms in atomic fountains such as the NIST-F1.

National standards agencies maintain an accuracy of 10-9 seconds per day (approximately 1 part in 1014), and a precision set by the radio transmitter pumping the maser. The clocks maintain a continuous and stable time scale, International Atomic Time (TAI). For civil time, another time scale is disseminated, Coordinated Universal Time (UTC). UTC is derived from TAI, but synchronized, by using leap seconds, to UT1, which is based on actual rotations of the earth with respect to the mean sun.

This text uses material from Wikipedia, licensed under CC BY-SA