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> It could be used, for example, to build an nuclear clock that could measure time more precisely than the best atomic clocks available today. Are today's atomic clocks really so imprecise? Without further explanation of this, it reminds me of this comic (which is alas showing its age both by mentioning flash, and by implying that 1024 is already a uselessly high number of cpus to support): https://xkcd.com/619/
What does "exciting a nucleus" mean?
Thorium-229 has two energy states. A ground state, and an excited isometric state. The laser is used to transition the nucleus from the ground state to the excited isometric state.
.. and given that it decays through gamma emission, does this mean we could now build an optically pumped gamma ray laser?
The measurement was already confirmed by a different group: https://arxiv.org/abs/2404.12311 This is important since impurities in the crystals used lead to all kinds of fluorescence that could be mistaken for a signal from the Thorium ions. Now two groups have seen exactly the same signal in different Thorium-doped crystals which is very covincing that they have found the actual nuclear transition.
Kind of weird that this new paper is only on the group's website [1] and not on the arXiv.
[1]: https://www.tuwien.at/fileadmin/Assets/tu-wien/News/2024/Tho...
Is there some direct application? Like using the excitation states of different atoms for storing information?
What does "exciting a nucleus" mean?
Applying energy to lift its electrons across a band gap. In this case, applying 8.35574 electron volts.