Researchers at Tsinghua University in China, working in collaboration with other scientific institutions, have developed a nuclear optical clock that uses energy transitions in atomic nuclei to measure time. The device, whose operation was demonstrated in a laboratory setting, represents an advance in high-precision measurement and could, in the future, contribute to improving satellite navigation systems, communications, and space exploration.

The development, presented in a study published in the scientific journal Nature, is based on the use of thorium-229, a radioactive isotope whose properties allow a frequency reference to be established from energy transitions in the atomic nucleus.

To build the device, the researchers developed a vacuum ultraviolet laser with a wavelength of 148.4 nanometres, capable of stimulating those transitions with high precision.

The team used calcium fluoride crystals containing thorium-229 nuclei and managed to stabilise the laser frequency based on the nuclei’s response to radiation. This process made it possible to transform nuclear transitions into an effective reference for measuring time.

According to Ding Shiqian, associate professor in the Department of Physics at Tsinghua University and researcher at the Beijing Academy of Quantum Information Sciences, the operating principle is similar to that of a pendulum clock.

While a traditional clock measures time by counting the oscillations of a pendulum, the nuclear clock uses a frequency associated with energy transitions in the atomic nucleus, corresponding to approximately two quadrillion cycles per second.

Nuclear Clocks Could Surpass Precision of Current Devices

Nuclear clocks are identified as a possible evolution of atomic clocks, which use electron energy transitions to establish time references.

Although current atomic optical clocks already allow measurements of high precision, their operation can be influenced by external disturbances, notably electric and magnetic fields.

Because atomic nuclei are generally less exposed to certain types of interference, using their transitions could enable the development of clocks that are more stable and less sensitive to external conditions.

This potential advantage does not mean, however, that the new devices already surpass the most advanced atomic clocks. The technology remains under development and requires improvements in the stability and control of measurement systems.

Satellite Navigation Among Future Applications

The evolution of nuclear clocks could benefit technological systems that require extremely precise time references.

Among the possible applications are satellite navigation systems, in which small differences in time measurement can translate into errors in determining positions and distances.

The technology could also contribute to improving the synchronisation of communication networks and support navigation systems used in space missions, including deep-space exploration.

Another possibility highlighted by the researchers is the development of more compact devices capable of operating outside specialised laboratories.

Despite the results achieved, the widespread use of these clocks will depend on further advances in equipment miniaturisation, measurement stability, and the availability of materials required for their operation.

The research thus opens the way for a new generation of timekeeping instruments, with potential for technological applications and fundamental physics experiments.

Source: Diário Económico
Original article: https://www.diarioeconomico.co.mz/?p=551861