The First Nuclear Clock Will Test if Fundamental Constants Change | Quanta Magazine
www.quantamagazine.org
An ultra-precise measurement of a transition in the hearts of thorium atoms gives physicists a tool to probe the forces that bind the universe.

An ultra-precise measurement of a transition in the hearts of thorium atoms gives physicists a tool to probe the forces that bind the universe.

  • shortwavesurfer@lemmy.zipEnglish
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    2 months ago

    So, I’m not quite sure I understand. I know that they use CZM atoms for atomic clocks, and they are extremely accurate. So, will this be used for atomic clocks, too? Or is it more accurate? Or is this for something totally different entirely? It appears to me as though this is something different entirely. But I don’t see why it could not be used for an atomic clock if it’s even more accurate than Seism.

    • Drunemeton@lemmy.worldEnglish
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      2 months ago

      It’s that t-229 can have its nucleus excited using far less energy than regular atomic clock nuclei.

      That leads to ultra precise excitation using wavelengths that cancel out some of the fundamental forces within the atom.

      That leads to us being able to monitor at a trillion to one ratio those forces based, in part, on mathematical ‘constants.’ In the excited state we can measure if there’s even the smallest variance in force, which in turn may mean that some ‘constants,’ aren’t.

      However the real testing of that is in the future as they estimate that a 10 trillion to one ratio is needed.

      Theory described a door, research defined the door and possibly what’s behind it, and experimentation just opened the door.

    • mark3748@sh.itjust.worksEnglish
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      2 months ago

      The Idaho researchers observed that reversing the intrinsic angular momentum, or “spin,” of thorium-229’s outermost neutron seemed to take 10,000 times less energy than a typical nuclear excitation. The neutron’s altered spin slightly changes both the electromagnetic and strong forces, but those changes happen to cancel each other out almost exactly. Consequently, the excited nuclear state barely differs from the ground state. Lots of nuclei have similar spin transitions, but only in thorium-229 is this cancellation so nearly perfect.

      Basically, thorium-229 can be excited by conventional lasers instead of gamma rays. Instead of millions of electron volts, it takes less than 10, which means it’s more reliable and more precise.

    • gasgiant@lemmy.mlEnglish
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      2 months ago

      My understanding is that current atomic clocks work on changing the state of whole atoms.

      Whereas this new method changes the state of part of the nucleus of an atom.

      Basically smaller is more precise. However given that current atomic clocks are one second out over something like a billion years I’ve no idea what benefit this extra preciseness will give us.

      We’ll probably start noticing really weird shit when we look at time that precisely. That’s generally what’s happened when we get into the quantum scale of things.