A New Era for Metrology and Science

The global metrology community stands on the brink of a transformative era with the launch of UNESCO’s International Year of Quantum Science and Technology. As quantum technologies begin to redefine the boundaries of science and industry, this year-long initiative highlights their growing importance across fields such as communication, computation and sensing. For metrology—the science of measurement—quantum advancements are not just an exciting frontier but an essential evolution, offering unprecedented levels of sensitivity and reliability.

Quantum’s Relevance to Metrology

Metrology has always been at the core of scientific progress, underpinning technological advancements and industrial growth. The integration of quantum principles into metrology is already reshaping how we define and measure fundamental quantities.

For example:

The 2019 revision of the SI provides a striking example of how quantum principles have reshaped metrology. Electrical units are now defined directly in relation to quantum phenomena, ensuring global uniformity. By anchoring the kilogram to the Planck constant, the new definition provides a stable and universally accessible standard for mass metrology. This shift replaces the dependence on a single, physical artifact—the International Prototype of the Kilogram—with a system that allows National Metrology Institutes worldwide to independently realize the kilogram with high levels of accuracy.

A key tool in this process is the Kibble balance (pictured below), which enables the practical realization of the kilogram by precisely measuring the relationship between mechanical power and electromagnetic power, the latter providing a direct link to the Planck constant.

Image Description: Depicted on the left, the International Prototype of the Kilogram, symbolizing the historical standard of mass. Depicted on the right, BIPM Principal Physicist Franck Biela is shown working on the Kibble balance, a modern instrument that realizes the kilogram based on the Planck constant.

Quantum technologies have also revolutionized timekeeping since 1967, when the second was redefined based on a hyperfine transition of the caesium-133 atom. This redefinition enabled the development of atomic clocks with extraordinary precision.

Today, a new generation of optical atomic clocks have achieved such precision that they can detect differences in gravitational potential at the centimetre scale. These advancements not only enhance the accuracy of Coordinated Universal Time (UTC) but also support critical applications such as global positioning systems, future space missions and fundamental physics experiments.

Image Description: On the left, a traditional analogue carriage clock, representing classic timekeeping. On the right, a scientist working on a Yb (ytterbium) optical lattice clock—an advanced timekeeping device known for its exceptional precision (image courtesy of and copyrighted to KRISS).

A Year of Celebration and Reflection

The International Year of Quantum Science and Technology underscores how far we have come as a global scientific community and how much further we can go.

From redefining the kilogram using Planck’s constant to advancing atomic clocks for hyper-accurate timekeeping, quantum metrology ensures that measurements remain at the forefront of innovation, supporting everything from global navigation systems to cutting-edge materials science.

"Advancements in quantum technologies open up new frontiers for precision measurement," said the Director of the Physical Metrology Department at the BIPM, Dr Michael Stock. "We remain committed to supporting the global metrology community in leveraging these innovations to achieve unprecedented levels of sensitivity and reliability across all scientific and industrial domains."

To delve deeper into these topics, we invite the scientific community to join us at two key events in 2025 that will delve deeper into quantum:

• The BIPM-UNESCO Symposium on May 20th: Held on World Metrology Day, this symposium will explore the broad impacts of metrology over the past 150 years and look ahead to its quantum-enabled future. As the primary event to mark the 150th Anniversary of the Metre Convention and the founding of the BIPM, this event offers a unique platform for interdisciplinary dialogue and opportunities to reflect on metrology’s role in driving innovation and societal progress.
• The Scientific Conference on May 21st-22nd: Taking place in Versailles, one of the key topics this conference will explore is that of cutting-edge quantum research and its applications in metrology. Beyond this, the conference explores topics such as the definition of the second, climate action and AI. It is an opportunity for the metrology community to exchange ideas and showcase groundbreaking work that pushes the boundaries of precision measurement.

Join the Conversation

The International Year of Quantum Science and Technology is a call to action for the global metrology community to embrace this quantum revolution. As we reflect on 150 years of metrological progress, let’s also envision a future shaped by quantum innovation.