China’s Thorium Nuclear Clock Six Times More Stable Than Vienna’s, Studies Show

Initial results from the world’s first two working nuclear clocks show that China’s timepiece is about six times as stable as the clock developed in Vienna, according to papers published this week in the journal Nature.

The findings offer the first comparison between the two independently developed devices, which are being pursued by Chinese and European teams in what researchers have described as a “fierce but friendly” competition to build next-generation timepieces.

The Chinese clock was developed by a team led by Tsinghua University in Beijing, while the European device was developed by researchers at Vienna’s TU Wien.

Both clocks use thorium-229 nuclei embedded in crystals. Instead of relying on electrons moving around an atom, as atomic clocks do, the devices keep time using the steady rhythm of the atom’s core.

That approach is central to the new generation of clocks because it uses the nucleus rather than the electrons surrounding it as the basis for timekeeping. The latest results indicate that the Chinese system currently has an advantage in stability, although the two teams developed their clocks separately.

The comparison follows a report by Nature in June that the teams had independently developed the new devices. At the time, Thorsten Schumm, a member of the European team, said, “now we have a fierce but friendly global competition”.

The Beijing scientists also reported that two crystals grown separately kept the same time. According to the researchers, this is a sign that the clocks could be reliably reproduced, an important consideration for further development of the technology.

The Vienna team, meanwhile, used its clock to search for dark matter, but the effort was unsuccessful. Together, the papers provide the first reported results from the two working nuclear clocks and show both the progress and the differing directions of the Chinese and European efforts.

Source: South China Morning Post