JapanNuclear clocks more precise than optical atomic clocks have the potential to help researchers discover dark matter.
Physicists at the RIKEN Quantum Metrology Laboratory, a national science institute in Japan, have made a breakthrough in the development of laser-based nuclear clocks. These nuclear clocks were improved by measuring the half-life of thorium-229 nuclei. The team successfully trapped thorium-229 ions and precisely measured their half-lives using lasers, Interesting Engineering August 18 news.
Unlike the best optical atomic clocks, which lose just one second every 30 billion years, nuclear clocks could help scientists discover dark matter. The next generation of nuclear clocks could become 10 times more accurate than optical atomic clocks because nuclei are less sensitive to external electromagnetic fields and temperature fluctuations than electrons, according to RIKEN.
To develop a new generation of more accurate atomic clocks, scientists used thorium-229 because its nucleus is less affected by external factors. The increased precision allows for the discovery of new physical phenomena. The team used a laser technique to trap thorium-229 ions and then measured their half-lives.
The researchers identified a promising approach to realizing atomic clocks by keeping thorium-229 ions that are missing three electrons (229Th3+). The advantage of such thorium ions is that they can be cooled with lasers. They are also easy to detect because they fluoresce when hit with a laser. Thorium-229 nuclei are particularly useful because they can be excited with ultraviolet lasers in a vacuum chamber. By measuring the half-lives of these ions, the team can ensure their efficient use in atomic clocks.
According to Atsushi Yamaguchi, a researcher at the RIKEN Quantum Metrology Laboratory, the half-life of the thorium-229 ion is just right. “If the half-life is too long, we can’t measure it, but if it’s too short, we can’t use the ion to make a high-precision nuclear clock,” Yamaguchi said.