Quantum Clock
Encyclopedia
A quantum clock is a type of clock that confines aluminum and beryllium ions together in an electromagnetic trap and cools them by laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

s to near absolute zero
Absolute zero
Absolute zero is the theoretical temperature at which entropy reaches its minimum value. The laws of thermodynamics state that absolute zero cannot be reached using only thermodynamic means....

 temperatures. Developed by National Institute of Standards and Technology
National Institute of Standards and Technology
The National Institute of Standards and Technology , known between 1901 and 1988 as the National Bureau of Standards , is a measurement standards laboratory, otherwise known as a National Metrological Institute , which is a non-regulatory agency of the United States Department of Commerce...

 physicists, the clock is 37 times more precise than the existing international standard. Both the aluminum based Quantum Clock and the mercury based atomic clock
Atomic clock
An atomic clock is a clock that uses an electronic transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element...

 keep track of time from the ion vibration at an optical frequency by using a UV laser, that is 100,000 times higher than the microwave frequencies used in NIST-F1
NIST-F1
NIST-F1 is a cesium fountain clock or atomic clock in the National Institute of Standards and Technology in Boulder, Colorado, and serves as the United States' primary time and frequency standard...

 and other similar time standards around the world. Quantum clocks like this are able to divide time into smaller units and can be far more precise
Accuracy and precision
In the fields of science, engineering, industry and statistics, the accuracy of a measurement system is the degree of closeness of measurements of a quantity to that quantity's actual value. The precision of a measurement system, also called reproducibility or repeatability, is the degree to which...

 than microwave standards.

The clock loses one second every 3.4 billion years, while the current international standard NIST-F1 caesium fountain atomic clock loses a second every 100 million years. Chou's team can't actually measure clock ticks per second because the definition of a second is based on the NIST-F1 which cannot measure a more precise machine. "The aluminum clock is very accurate because it is insensitive to background magnetic and electric fields, and also to temperature".

In February 2010, NIST physicists built a second, enhanced, version of the quantum logic clock using a single aluminum atom. Considered the world's most precise clock, it offers more than twice the precision of the original.

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