Scientists have made a major step towards the ambitious Global objective of “redefining the second” at the end of this decade. A study Posted this week Details how researchers from six different countries compared the measures of 10 optical clocks – an advanced shape of chronometer that is up 100 times more precise than the best cesium clockswhich are currently used as a global standard.
The measures represent the most important coordinated comparison of optical clocks to date and have considerably reduced the uncertainty between the measures reported in previous studies. It also means that optical clocks are closer than ever to become the new standard for the stopwatch, a change that could have a massive training effect on everything, from meteorology to our understanding of fundamental physics.
The researchers say that the results support “the advance towards a redefinition of the second and the use of optical standards for international time scales”.
What are optical clocks?
In a word, optical clocks are incredibly precise instruments that measure the frequency of atoms after being excited by lasers. The atoms are first cooled to an almost absolute zero, then the lasers are used to detect their vibrations. These vibrations are called frequency ratios. This precise frequency then corresponds to the “tick” of a second. Scientists believe that this method gives much more precise results than the atomic clock clocks, which have been the global standard for five decades. For the context, researchers say that an optical clock would not win or lose a second for billions of years. Actually, New scientist Estimates you could wait until the current age of the universe four times, and an optical clock would always be deactivated less than a minute. Compare this to a typical wristwatch, which can derive over a few months.
The optical clocks are incredibly precise, but they are also very complex. There are about 100 of them around the world, largely because they are difficult to build, exploit and maintain – they are also likely to break. Compare them to each other is notoriously difficult. Different clocks measure the frequencies of different types of atoms, each with its own single frequency. This means that the only way to establish a coherent and very precise standard is to directly compare clocks between them. This is where these most recent results come into play.
Researchers from Finland, France, Germany, Italy, the United Kingdom and Japan have collaborated on a project led by Europe called Rocit To compare 10 different clocks. The measurements were carried out over a period of 45 days in 2022. In the past, the smaller optical clock comparisons were based on satellite connections to measure differences, but this study used both satellite links and fiber optic cables. This is important because it allows more precise measures.
“Compare several clocks at the same time and use more than one type of bond technology provides much more information than clock comparisons mainly in pairs that have been carried out to date”, the main scientist of mountain biking Mikes Meteorology Research Center Thomas Lindvall said in a press release.
In relation: (Refine the second of the clock takes time and lasers))
Optical fiber cables have lasted thousands of kilometers across Europe, allowing researchers to connect the frequency outings of the different clocks. They took into account the sound of the signal and other limits of the instruments during the process. In total, the comparison produced 38 different frequency reports measured simultaneously, four of them for the first time. The remaining reports have been measured with greater precision than ever before, according to the researchers.
“These measures provide essential information on the work necessary for optical clocks to achieve the precision and reliability required for use in the international stopwatch”, the principal researcher of the Nazional Instituto Di Ricerca (INRIM) Marco Pizzocaro said in a press release. “Our experience has also shown how optical clocks across Europe can be linked to measure frequency relationships with advanced precision.”
More precise could help reveal mysteries on the universe
Although more comparisons are needed before optical clocks can officially become the global standard, researchers are optimistic about the future. The advantages go beyond the improvement of the chronometer. More specific measures could help scientists test Relativity theory with greater precision and offer new perspectives on calmmysterious concept of dark matter.
At the same time, scientists also make completely new progress “nuclear clocks“It could make optics look like relics. Last year, the National Institute of Standards and Technology (NIST) said they were about to finish a nuclear clock prototype that focuses on vibrations, not one atom, but one core.
“Imagine a wristwatch that would not lose a second even if you have left it for billions of years,” said physicist Nist and Jila Jun said last year after the news of the prototype. “Although we are not yet quite there, this research brings us closer to this level of precision.”
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