Rare Earth and its essential role in the development of the most accurate clock in the world

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Rare Earth and its essential role in the development of the most accurate clock in the world

The race to build the most accurate clock in the world is in full swing, and the rare earth elements -very required nowadays- will be key in the process.
 Barrett, in the background downtown | Center for Quantum Technologies
Barrett, in the background downtown | Center for Quantum Technologies
The Lanthanides, better known as Rare Earth Elements or REE, are a series of 17 minerals that have gained strength in recent months, since they have positioned themselves as strategic elements in the commercial struggle between China and the United States.
Mainly, the attention that these metals have received is due to their multiple uses in cutting-edge technology, such as electric vehicles, consumer electronics, renewable energy and security elements,-radars and lasers-, among others.
Therefore, it is not surprising that from time to time new uses of these minerals are revealed, whose applications in the framework of current technological development are, until now, unsuspected.
Just a few days ago we heard about the case of Murray Barrett, associate professor of physics at the National University of Singapore (NUS), who during the last time has focused on an investigation that could revolutionize the way we see and have the time: the most accurate clock in the world, based on a rare earth element called lutetium.
Barrett’s atomic clock, located at the NUS Center for Quantum Technologies, intends to divide time into smaller and smaller segments than any other clock.
“An analog stopwatch can typically divide the second into 10 pieces: 0.1 second, 0.2 second, etc. The lutetium clock will, in theory, add 14 zeros to the right of that decimal point, thereby segmenting the second into (roughly) a quadrillion pieces, and remain accurate to within a second if left running continuously for 30 billion years. Even the smallest vibrations from, say, the exhaust fans that keep the laboratory environment clean are enough to upset that precision—and with it, all the lab’s work”, said Bloomberg in an article dedicated to Barrett’s work.
The atomic lutetium clock at the National University of Singapore | Bloomberg
If Barrett and his laboratory manage to position his watch as the most accurate in the world, they would make Lutetium one of the key elements for technological development and even, as defined by Bloomberg, it could become “the heart of global science and economics“.
The above, because lutetium is exceptionally insensitive to temperature changes. “And I would say, any atom that has the least sensitivity to its environment will make the clock better,” said the expert.
Currently, the most used element in the precision of watches has been cesium. But the cesium rule measures in centimeters, unlike a lutetium-based clock that would measure in millimeters and, therefore, allow the world to be measured more accurately. Its importance is such that it could even measure things that have never be measured before, revealing and solving fundamental issues of physics such as the general theory of relativity of Albert Einstein, which postulated that the faster we travel, the more gravity pulls on us and the more time slows down.

In search of the ‘Element of Precision’

In the last 20 years, scientists around the world have dedicated themselves to improving atomic clocks that stimulate atoms using visible light, which would be approximately 100 thousand times faster than microwaves in a cesium clock. But this work not only has the need to overcome a series of scientific and technical challenges, but also to determine which element is the most appropriate to tell the time.
Currently, the favorite seems to be another element of Rare Earth, Yerbium, which is being investigated by large and well-funded teams at the United States National Institute of Standards and Technology (NIST) and laboratories in Europe and Asia.
In 2018, NIST reported that a pair of iterbium-based watches had reached records of accuracy, stability and reproducibility of results. In this context, Lutetium had a late entry to the competition but, in a relatively short time, it has risen as a relevant mineral thanks to the work of Murray Barrett.
“My argument is, if you can make an accurate clock in ytterbium, then you must be able to make an accurate clock in lutetium, and it should be more accurate because the properties are just better”, the expert concluded.
Therefore, in the not too distant future, it is likely that the basis of the world’s most accurate watches require lutetium and ytterbium minerals, two of the strategic Rare Earth elements in global technological development.