211–220 of 229 posts
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Nice to hear the octave relation used! "blue above visible blue" is a good name.. hmm, a little web tool to name these would be neat ;)
> "blue above visible blue" Good name for a rock band. Or some tv series.
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I've heard "handegg" before but a football is not shaped like an egg, it's vaguely egg-like but the teardrop shape of an egg is distinctly not what a football looks like.
It looks more like an egg than it looks like a ball, so if we have to force fit into a common word, my vote goes for egg
> If the wavelength of the laser is chosen exactly right ... then maybe a special atomic nucleus could be manipulated with a laser, namely thorium-229. On November 21, 2023, the team was finally successful: the correct energy of the thorium transition was hit exactly, the thorium nuclei delivered a clear signal for the first time. So what's the wavelength? I felt like the article left me hanging. The answer is: 148.3…
UV 385nm
Blue 450nm
Green 525nm
Red 630nm
IR 880nmFrom the paper, the light is UV-C at around 140nm or 8.4 eV. But it has to be very precisely the right energy to cause the transition, since nuclear states don’t have any place to dump excess energy to.
When you stop and look at QCD in the big picture, it's sort of shocking how little we know - like, really, really know - about the internal structure of the proton, or even the nucleon! It's the curse of "probing" with massive energies. No one's a hundred percent certain of whether they're detecting something that's actually there - like there there - or whether they're looking at by-product of enormous collision ene…
> it's sort of shocking how little we know To my feeble mind, it's shocking how much we know.
> But it is not just time that could be measured much more precisely in this way than before. For example, the Earth's gravitational field could be analyzed so precisely that it could provide indications of mineral resources or earthquakes This has military applications as well, right? Replacing GPS for nuclear submarines. https://news.ycombinator.com/item?id=29213751 https://news.ycombinator.com/item?id=36222625
An obvious question is whether this be used to build a nuclear analogue of a laser, using nuclear transitions instead of electron transitions. It turns out to have already been asked: https://physics.stackexchange.com/questions/296237/nuclear-t... In summary, the answer seems to be "maybe, but why?". The laser was originally called "a solution in search of a problem", which would suggest that "why" isn't really a rea…
To build a laser, you would need at least three energy levels, and ideally four, with particular constraints in the transition probabilties so that you can create population inversion. And you would need to pump it with a higher-energy (shorter wavelength) laser. Perhaps doable with a free electron laser, but probably not with traditional lasers, due to the energies involved. But, yeah, not sure what the use would be…
"Solid-state 229 Th nuclear laser with two-photon pumping"
> If the wavelength of the laser is chosen exactly right ... then maybe a special atomic nucleus could be manipulated with a laser, namely thorium-229. On November 21, 2023, the team was finally successful: the correct energy of the thorium transition was hit exactly, the thorium nuclei delivered a clear signal for the first time. So what's the wavelength? I felt like the article left me hanging. The answer is: 148.3…
https://en.wikipedia.org/wiki/Gamma_ray#Distinction_from_X-r...
No one WOULD call them gamma rays, but just a fun thought!
When you stop and look at QCD in the big picture, it's sort of shocking how little we know - like, really, really know - about the internal structure of the proton, or even the nucleon! It's the curse of "probing" with massive energies. No one's a hundred percent certain of whether they're detecting something that's actually there - like there there - or whether they're looking at by-product of enormous collision ene…
> it's sort of shocking how little we know To my feeble mind, it's shocking how much we know.
Yes, I knew they weren't balls, exactly, but still. Newer models with greater sensitivity have sort of pulled a fast one: that maybe the balls are a side effect of the way we look at them. More precisely, to look at them, we need to smack them hella hard, to make the balls come out where we can see them. But the smacking might be a part of why the balls look like balls!
The native hadron in its natural habitat might be something fantastically more complex, a sort of cell biology of energies all competing and vibrating, and they're part of the interrelated forces of the nucleus itself - we might even use that obsolete term return, the "nucleon", to represent this complex. Jiving against all of this are new ideas about what mass actually is, defining spatial attributes as degrees of freedom, and all sorts of new thoughts. It's super exciting.
So that's what I mean by "shocked how little we know", because what we did think we knew got oversold as a World of Balls.
But who knows?! Maybe this neat laser thing can help find more answers.
Earlier quoted context omitted.
To build a laser, you would need at least three energy levels, and ideally four, with particular constraints in the transition probabilties so that you can create population inversion. And you would need to pump it with a higher-energy (shorter wavelength) laser. Perhaps doable with a free electron laser, but probably not with traditional lasers, due to the energies involved. But, yeah, not sure what the use would be…
this may interest you: "Solid-state 229 Th nuclear laser with two-photon pumping" http://web.mit.edu/pcappell/www/pubs/Xu23a.pdf [pdf]
Still not clear what it would be useful for outside of clocks, but definitely a very cool physics project, and I'm sure someone would find other uses eventually.