Nuclear spectroscopy breakthrough could rewrite the fundamental constants of nature. From atomic to nuclear clocks

Good news! Exact and accurate chronometry has come a long way!

I wish physicists would not have this annoying habit of using all these special symbols you can not find on your computer keyboard!

"Key takeaways

• Raising the energy state of an atom’s nucleus using a laser, or exciting it, would enable development of the most accurate atomic clocks ever to exist. This has been hard to do because electrons, which surround the nucleus, react easily with light, increasing the amount of light needed to reach the nucleus.
• By causing the electrons to bond with fluorine in a transparent crystal, ...  physicists have finally succeeded in exciting the neutrons in a thorium atom’s nucleus using a moderate amount of laser light.
• This accomplishment means that measurements of time, gravity and other fields that are currently performed using atomic electrons can be made with orders of magnitude higher accuracy.

...
The achievement would allow today’s atomic clocks to be replaced with a nuclear clock that would be the most accurate clock to ever exist ...
This means that measurements of time, gravity and other fields that are currently performed using atomic electrons can be made with orders of magnitude higher accuracy. The reason is that atomic electrons are influenced by many factors in their environment, which affects how they absorb and emit photons and limits their accuracy. Neutrons and protons, on the other hand, are bound and highly concentrated within the nucleus and experience less environmental disturbance. ...

propose a series of experiments to stimulate thorium-229 nuclei doped into crystals with a laser, and has spent the past 15 years working to achieve the newly published results.  ...

The ... team embedded thorium-229 atoms within a transparent crystal rich in fluorine. Fluorine can form especially strong bonds with other atoms, suspending the atoms and exposing the nucleus like a fly in a spider web. The electrons were so tightly bound with the fluorine that the amount of energy it would take to excite them was very high, 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. By changing the energy of the photons and monitoring the rate at which the nuclei are excited, the team was able to measure the energy of the nuclear excited state. ..."

From the abstract:

"LiSrAlF6 crystals doped with 229 Th are used in a laser-based search for the nuclear isomeric transition. Two spectroscopic features near the nuclear transition energy are observed. The first is a broad excitation feature that produces redshifted fluorescence that decays with a timescale of a few seconds. The second is a narrow, laser-linewidth-limited spectral feature at 148.382 19⁢(4)stat⁢(20)sys  nm [2⁢020 407.3⁢(5)stat⁢(30)sys  GHz] that decays with a lifetime of 568⁢(13)stat⁢(20)sys  s. This feature is assigned to the excitation of the 229 Th  nuclear isomeric state, whose energy is found to be 8.355 733⁢(2)stat⁢(10)sys  eV in 229  Th :LiSrAlF6."

Nuclear spectroscopy breakthrough could rewrite the fundamental constants of nature | UCLA The findings could unlock the most accurate clock ever and allow advances like deep space navigation, communication

Laser Excitation of the 229 Th Nuclear Isomeric Transition in a Solid-State Host (no public access)

When trapped in a transparent, flourine-rich crystal, scientists can use a laser to excite the nucleus of a thorium-229 atom.