Physicists have successfully excited an atom’s nucleus using a laser, a groundbreaking achievement that could lead to the development of a new type of atomic clock. This nuclear clock would be significantly more accurate than existing atomic clocks, allowing for advances in deep space navigation and communication. It could also enable scientists to measure precisely whether the fundamental constants of nature, such as the fine-structure constant, vary over time or space.
The team, led by Eric Hudson of UCLA, embedded a thorium atom within a highly transparent crystal and bombarded it with lasers. By choosing a crystal rich in fluorine, they were able to suspend the atoms and expose the nucleus, allowing lower energy light to reach the nucleus. The thorium nuclei could then absorb these photons and re-emit them, allowing the excitation of the nuclei to be detected and measured.
This new technology could have numerous commercial applications, as a thorium-based nuclear clock would be smaller, more robust, more portable, and more accurate than existing atomic clocks. Beyond commercial uses, the new nuclear spectroscopy could help scientists unlock some of the universe’s biggest mysteries. Sensitive measurement of an atom’s nucleus opens up a new way to learn about its properties and interactions with energy and the environment, potentially leading to new insights about matter, energy, and the laws of space and time.
The new technique could provide the most sensitive test of whether fundamental constants vary to date, and it is likely that no experiment for the next 100 years will rival it. This work represents a significant step towards more precise measurements and potentially a rewriting of some of the most basic laws of nature.
The results of this research were published in the journal Physical Review Letters. The team’s proposal for a series of experiments to stimulate thorium-229 nuclei doped into crystals with a laser has been in development for 15 years. The achievement of these seemingly impossible feats opens up a new era of nuclear spectroscopy and atomic clock technology.
