Does the era of atomic clocks are coming to an end? The question now deserves to be asked after the publication of a series of new remarkable studies on nuclear clocks, which could well revolutionize communications as well as fundamental physics.
Today, the ability of humanity to measure time with phenomenal precision is largely based on atomic clocks. These incredibly efficient timing instruments are able to remain perfectly precise for millions – even billions – years. They therefore radically changed the face of our civilization by supporting all of the modern communication and navigation systems, but also by paving the way for countless major discoveries in science.
A stability problem
But as great they may be, these devices are not perfect, however: they suffer from a stability problem. These are exceptionally delicate machines, because they are based on a phenomenon relatively sensitive to the vagaries of the environment.
The nuclei of certain atoms are constantly running on themselves, which gives them magnetic properties. In parallel, they are surrounded by electrons spread over different orbits which correspond to different energy levels. They too have magnetic properties. The interactions between these two magnetic systems give rise to a somewhat special phenomenon: electrons can exist at different distinct energy levelsseparated by a tiny but nevertheless measurable difference.
When the atom is bombarded with perfectly calibrated electromagnetic waves, it gets to Alternate between these energy levels at a very high pace and above all incredibly precise. For example, Cesium-133 which is used in many atomic clocks very exactly 9,192,631,770 times per second when it floods it with microwaves. It is this exceptional regularity that is used in atomic clocks to timed events with breathtaking precision.
The concern is that this nanometric ballet can be jostled by fluctuations in the magnetic or gravitational field, by temperature changes, or even electromagnetic interference. Physicists therefore seek to develop new just as precise, but much more resilient measurement systems.
Nuclear clock, a rapidly evolving concept
Today, the most promising track is embodied by nuclear clocks. This concept is based on the constituents of the nuclei of atoms rather than on the electrons that surround them. In the same way as electrons, protons and neutrons may exist at different energy levels, and the transition between these different states can absorb or emit electromagnetic radiation at given frequencies. Using a perfectly calibrated laser, we can therefore generate rapid and very precise oscillations from one state to another to measure the passage of time, as the atomic clocks do with the electrons.
Functionally speaking, the principle is therefore quite similar. On the other hand, Constituents of the atom nucleus are much less sensitive to environmental factors than electrons. On paper, they could therefore make it possible to build much more stable clocks.
Unfortunately, at present, this idea remains above all theoretical. Even if experimental prototypes have started to emerge in recent years, nuclear clocks are still far from being mature enough to replace their atomic counterparts … but that could well change in the near future.
Proof of promising concept
In any case, this is the observation that is essential when we think about the latest work of the joint Institute for Laboratory Astrophysics, or Jila, a prestigious American research laboratory. In the space of a few months, its residents have signed several major progress in the field of nuclear clocks.
Last year, Jun Ye’s team gave birth to a remarkable study carried out jointly with the Vienna Technical University. This group has proven for the first time that the nuclear transitions of Thorium-229, integrated into a calcium fluoride crystal, could actually allow time to measure with great precision.
A very exciting proof of concept, of course – but it was still necessary to determine whether this system was capable of reaching the level of stability sought. And that’s what the authors started to do in a new study.
This same mixed team analyzed the way in which this crystal doped in thorium reacts to extreme temperature variations. Unsurprisingly, the researchers observed that these changes directly affect the structure of the crystal, and by extension, the nature of the energy transitions of neutrons and protons.
But by doing so, they also identified a very specific type of transition which has proven almost invulnerable to these temperature variations, and remained Surprisingly stable of -123 ° C at 20 ° C. A very promising discovery, and for good reason: this suggests that by still refining the system a little, it will actually be possible to use it to build the first high -stability operational nuclear clock.
« This transition takes place in a very promising way for time measurement applications Summarizes Chuankun Zhang, researcher at Jila. “” If we manage to stabilize it more, it could revolutionize precision timing. »
Much more than a super-chronometer
But this discovery also has another even more interesting involvement. According to Scitechdaily, if this crystal is very little vulnerable to the variations in the environment, it remains however extremely sensitive to variations in fundamental forces… Starting with the gravitation, which we know is intimately linked to time thanks to the work of Einstein on relativity.
In practice, this means that such a nuclear clock would be much more than a “simple” high performance chronometer. Any unexpected variation of its frequency could directly point to unknown physical phenomenaand potentially very useful for reconciling relativity with particle physics in the famous ” Theory at all – The ultimate goal of Einstein and many modern physicists.
« The sensitivity of the nuclear transition could allow us to explore a new physics “Explains Jacob Higgins, principal author of the study. “” Beyond the simple design of a better clock, this could open the way for study methods of the entirely new universe. »
Admittedly, there is still a lot of work to hope to get there. But it will still be necessary to follow the next work of this team, because they could well lead us straight towards a new generation of instruments likely to launch a small revolution in fundamental physics. A whole program!
The study text is available here.
🟣 To not miss any news on the Geek Journal, subscribe to Google News. And if you love us, .
