10 ms·

This seems like something that wouldn't even be written about in sci-fi books because it just doesn't make sense to ever be possible. It seems impossible to eve

This seems like something that wouldn't even be written about in sci-fi books because it just doesn't make sense to ever be possible. It seems impossible to even imagine the implications. I also can't imagine future chemistry students needing to memorize two separate sets of electron and antiproton orbitals.

Pulcinella 5y ago
Note that this isn’t the first time these kind of “exotic” atoms have been created. https://en.m.wikipedia.org/wiki/Exotic_atom https://en.m.wikipedia.org/wiki/Exotic_atom https://en.m.wikipedia.org/wiki/Antiprotonic_helium https://en.m.wikipedia.org/wiki/Antiprotonic_helium https://en.m.wikipedia.org/wiki/Antihydrogen https://en.m.wikipedia.org/wiki/Antihydrogen
- datameta 5y ago
  Also of note is the fact that this is the first time they were able to get data granular enough to be of use.
gus_massa 5y ago
From Wikipedia: https://en.wikipedia.org/wiki/Antiprotonic_helium https://en.wikipedia.org/wiki/Antiprotonic_helium > The antiproton can thus orbit the nucleus for tens of microseconds, before finally falling to its surface and annihilating. From the research article: https://www.nature.com/articles/s41586-022-04440-7 https://www.nature.com/articles/s41586-022-04440-7 > The resonance parent states (37, 35) and (39, 35) have microsecond-scale lifetimes, whereas the daughter state (38, 34) has an Auger width ΓA ≈ 21 MHz (ref. 7; Fig. 1b) The life of the antiproton here is too short to make an interesting chemistry experiment, but it's long enough to measure the spectral lines.
- ethbr0 5y ago
  Dumb question: Why does the antiproton fall to the nucleus' surface, after orbiting?
  - puzzledobserver 5y ago
    I am not a physicist, but I suppose it is because the s-orbital has an amplitude peak at r=0? In other words, it is not so much the antiproton falling to the nuclear surface as much as the antiproton finding itself at the nuclear surface. EDIT: The context is that the antiproton was in an orbital with large principal and azimuthal quantum numbers. Still, there would be some non-zero probability of the antiproton finding itself close to the nucleus, no?
    - jbay808 5y ago
      Could we keep it perpetually in an excited state that has no amplitude at the centre?
      - marcosdumay 5y ago
        It reaches the nucleus by a process of tunneling. You can never completely stop it, but it reacts exponentially to you increasing a barrier.
        jbay808 5y ago
        An excited state isn't a barrier, it's a state with a higher energy than ground state. Several non-ground-state orbitals have a wavefunction whose amplitude drops to zero toward the centre. An electron won't tunnel to a location where its wavefunction amplitude is zero.
        zardo 5y ago
        Practical applications, a laser that explodes if you turn it off.
  - TobTobXX 5y ago
    Not too literate in this, but I'd say that the mass of a proton is large enough so that quantum effects (such as the quantization of of energy) become less relevant than classical mechanics (which lets the antiproton get pulled toward the proton). Correct me if I'm wrong though.
- BitwiseFool 5y ago
  It's been a long time since chemistry and physics class, but isn't "orbital" in this context not the same thing as gravitational orbits? I was told the concept of orbitals represented where an electron could exist around a nucleus and that it wasn't actually traveling in a path bound by the gravity of the atom. So in this context, how is it actually falling into it's surface? Is it just tunneling into contact?
  - deleted 5y ago
    [deleted]
  - hateful 5y ago
    Disclaimer: Not a physicist, but have been watching many youtube videos. So please correct me if I'm thinking of this wrong. An electron is bound to the nucleus by the electromagnetic force, but is not a round ball, but a wave distribution of probabilities. I don't know if it's the actual case, but I've been thinking of all "particles" like "waves" in a pool. Small disturbances in the fields (e.g. electromagnetic), like jumping in a pool. The electron IS the disturbance, because to us that is what we can measure (and we can only measure one place at a time). So the electron doesn't rotate around the nucleus - instead its a wave in the same area where the nucleus is. The electron's "probability wave" disturbs the space around the nucleus - including inside it, and 1000 miles away from it. It's just has way more disturbance in certain places - AKA "the shell" its in. Just like any wave, it "fades" with distance but who's to say where the wave ends. In fact, that wave isn't exactly the same for every electron. Each "shell" is waving at a different amplitude (is amplitude the right analogy?) - and you can only have so many "waves" add up in a shell simply because there's no more room because of the length of each wave (like a spiral-o-graph). You can only put another wave in the gaps of the previous wave (if you did put two in the same place, it would double and be part of the next shell, right?). And when an electron's amplitude changes, e.g. is lowered, the total energy can't be destroyed, so the difference is emitted as another wave of the difference - that wave is a photon. And the same applies when a photon is added to that wave. Like rowing in the water - the exiting wave and the rowed wave is added together. I think of Photons are partial Electrons. They are like the "wake" of an electrons wave change.
    - 5y ago

Pulcinella 5y ago

Note that this isn’t the first time these kind of “exotic” atoms have been created. https://en.m.wikipedia.org/wiki/Exotic_atom https://en.m.wikipedia.org/wiki/Exotic_atom https://en.m.wikipedia.org/wiki/Antiprotonic_helium https://en.m.wikipedia.org/wiki/Antiprotonic_helium https://en.m.wikipedia.org/wiki/Antihydrogen https://en.m.wikipedia.org/wiki/Antihydrogen

datameta 5y ago
Also of note is the fact that this is the first time they were able to get data granular enough to be of use.

gus_massa 5y ago

From Wikipedia: https://en.wikipedia.org/wiki/Antiprotonic_helium https://en.wikipedia.org/wiki/Antiprotonic_helium > The antiproton can thus orbit the nucleus for tens of microseconds, before finally falling to its surface and annihilating. From the research article: https://www.nature.com/articles/s41586-022-04440-7 https://www.nature.com/articles/s41586-022-04440-7 > The resonance parent states (37, 35) and (39, 35) have microsecond-scale lifetimes, whereas the daughter state (38, 34) has an Auger width ΓA ≈ 21 MHz (ref. 7; Fig. 1b) The life of the antiproton here is too short to make an interesting chemistry experiment, but it's long enough to measure the spectral lines.

ethbr0 5y ago
Dumb question: Why does the antiproton fall to the nucleus' surface, after orbiting?
- puzzledobserver 5y ago
  I am not a physicist, but I suppose it is because the s-orbital has an amplitude peak at r=0? In other words, it is not so much the antiproton falling to the nuclear surface as much as the antiproton finding itself at the nuclear surface. EDIT: The context is that the antiproton was in an orbital with large principal and azimuthal quantum numbers. Still, there would be some non-zero probability of the antiproton finding itself close to the nucleus, no?
  - jbay808 5y ago
    Could we keep it perpetually in an excited state that has no amplitude at the centre?
    - marcosdumay 5y ago
      It reaches the nucleus by a process of tunneling. You can never completely stop it, but it reacts exponentially to you increasing a barrier.
      - jbay808 5y ago
        An excited state isn't a barrier, it's a state with a higher energy than ground state. Several non-ground-state orbitals have a wavefunction whose amplitude drops to zero toward the centre. An electron won't tunnel to a location where its wavefunction amplitude is zero.
        zardo 5y ago
        Practical applications, a laser that explodes if you turn it off.
- TobTobXX 5y ago
  Not too literate in this, but I'd say that the mass of a proton is large enough so that quantum effects (such as the quantization of of energy) become less relevant than classical mechanics (which lets the antiproton get pulled toward the proton). Correct me if I'm wrong though.
BitwiseFool 5y ago
It's been a long time since chemistry and physics class, but isn't "orbital" in this context not the same thing as gravitational orbits? I was told the concept of orbitals represented where an electron could exist around a nucleus and that it wasn't actually traveling in a path bound by the gravity of the atom. So in this context, how is it actually falling into it's surface? Is it just tunneling into contact?
- deleted 5y ago
  [deleted]
- hateful 5y ago
  Disclaimer: Not a physicist, but have been watching many youtube videos. So please correct me if I'm thinking of this wrong. An electron is bound to the nucleus by the electromagnetic force, but is not a round ball, but a wave distribution of probabilities. I don't know if it's the actual case, but I've been thinking of all "particles" like "waves" in a pool. Small disturbances in the fields (e.g. electromagnetic), like jumping in a pool. The electron IS the disturbance, because to us that is what we can measure (and we can only measure one place at a time). So the electron doesn't rotate around the nucleus - instead its a wave in the same area where the nucleus is. The electron's "probability wave" disturbs the space around the nucleus - including inside it, and 1000 miles away from it. It's just has way more disturbance in certain places - AKA "the shell" its in. Just like any wave, it "fades" with distance but who's to say where the wave ends. In fact, that wave isn't exactly the same for every electron. Each "shell" is waving at a different amplitude (is amplitude the right analogy?) - and you can only have so many "waves" add up in a shell simply because there's no more room because of the length of each wave (like a spiral-o-graph). You can only put another wave in the gaps of the previous wave (if you did put two in the same place, it would double and be part of the next shell, right?). And when an electron's amplitude changes, e.g. is lowered, the total energy can't be destroyed, so the difference is emitted as another wave of the difference - that wave is a photon. And the same applies when a photon is added to that wave. Like rowing in the water - the exiting wave and the rowed wave is added together. I think of Photons are partial Electrons. They are like the "wake" of an electrons wave change.
  - 5y ago