A nuclear clock prototype hints at ultraprecise timekeeping 

Scientific clockmakers have crafted a prototype of a nuclear clock, hinting at future possibilities for using atomic nuclei to perform precise measurements of time and make new tests of fundamental physics theories.

While the definition of a “clock” is scientifically hazy, the prototype is now not yet used to measure time. So it technically ought to be often also is named a “frequency usual,” physicist Jun Ye says. Nonetheless the work brings scientists closer to a nuclear clock than ever before. “For the first time, all important ingredients for a working nuclear clock are contained in this work,” says Ye, of JILA in Boulder, Colo.

Whereas atomic clocks measure time in keeping with electrons jumping between energy levels in atoms, nuclear clocks’ timekeeping would rely on the energy levels of atomic nuclei. A undeniable frequency of laser light is required for an atom or an atomic nucleus to make the sort of jump. The wiggling of that light’s electromagnetic waves should be used to mark time.

Nuclear clocks would keep time using a choice of the element thorium, often also is named thorium-229. Most atomic nuclei make energy leaps so it is nice to be would becould o.k. be too large to be triggered by a tabletop laser. But thorium-229 has two energy levels so it is nice to be would becould o.k. be close enough to every other that the transition between those two levels may maybe serve as a clock.

Now, researchers have precisely determined the frequency of the light needed to set off that jump. It’s 2,020,407,384,335 kilohertz, Ye and colleagues report during the Sept. 5 Nature.

Importantly, the measurement has an uncertainty of 2 kilohertz. That’s greater than 1,000,000 times the precision of a suitable previous measurement. And it’s greater than 1000000000 times the precision to which that frequency was known just over a year ago, highlighting multiple back-to-back developments.

The development hinged on a component often also is named a frequency comb (SN: 10/5/18). A important element of many atomic clocks, a frequency comb creates an array of discrete frequencies of light. The use of a frequency comb with thorium-229 has been a major research goal, for some scientists (SN: 6/four/21). The complete way through the emblem new work, Ye and colleagues when put next the nuclear clock transition with that of an atomic clock with a known frequency.

“Which is something with a view to be important as a scientific application for tests of fundamental physics,” says physicist Ekkehard Peik of the National Metrology Institute in Braunschweig, Germany, who was now not involved with the emblem new research.

The complete way through the longer term, such comparisons should be used to hunt for weird and wonderful physics effects, equivalent to drifting of the values of fundamental constants (SN: 11/2/16). These are numbers that — because the name implies — are believed to be eternally unwavering.