The NIST-F1 atomic clock that currently serves as primary time and frequency standard for the U.S. is expected to neither gain nor lose a second in more than 100 million years. That might sound pretty accurate, but a proposed nuclear clock could make it look like a cheap digital wristwatch. It is claimed that the proposed clock would neither gain nor lose 1/20th of a second in 14 billion years. To put that in context, that’s the estimated age of the universe.
In the simplest terms, atomic clocks use the orbiting electrons of an atom – in the case of NIST-F1, cesium 133 – as a clock pendulum. But researchers from the University of New South Wales (UNSW), the Georgia Institute of Technology and the University of Nevada say that relying on nuclear physics, rather than atomic physics, would enable a clock that is accurate to 19 decimal places and nearly 100 times more accurate than the most accurate atomic clocks in use today.
“We have shown that by using lasers to orient the electrons in a very specific way, one can use the orbiting neutron of an atomic nucleus as the clock pendulum, making a so-called nuclear clock with unparalleled accuracy,” says Professor Victor Flambaum, the Head of Theoretical Physics in the UNSW School of Physics.
Unlike atomic clocks, whose sample electrons are relatively loosely bound making them more susceptible to external pertubations that can affect their oscillation rate, nuclear clocks would retain their accuracy for much longer as the neutron is held so tightly to the nucleus.
Professor Flambaum says a nuclear clock, "would allow scientists to test fundamental physical theories at unprecedented levels of precision and provide an unmatched tool for applied physics research.”
The research team’s paper is published in the journal Physical Review Letters.
Source: University of New South Wales