> thorium crystal clock
Take note, science fiction writers.
Atomic nucleus excited with laser: A breakthrough after decades
171–180 of 229 posts
Re: Atomic nucleus excited with laser: A breakthrough after decades
#172Earlier quoted context omitted.
148nm is on the lower end of UV-C. It's higher-energy than the furthest ultraviolet light that the sun produces (200nm). If it were produced artificially, it'd be heavily absorbed by the atmosphere to the point of near opacity. If the visible spectrum was an octave, where the "tone" of a color wrapped around from red back to blue the way G wraps to A, it'd be the blue one octave above visible blue.
Teeny nit, the sun produces light well into the x-rays (mostly from the corona though). You're probably talking about sunlight making it through the atmosphere.
I'm talking about the blackbody radiation of the sun's surface, which accounts for almost all of the light. The X-ray flux at earth is 11 orders of magnitude lower than the blackbody-related flux.
Re: Atomic nucleus excited with laser: A breakthrough after decades
#173From 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.
Where do electron transitions usually dump excess energy?
In general it's possible for electrons to jump to sub-orbitals which gives them a wider band of wavelengths that they can emit and absorb photons. The jumps between sub-orbitals are usually in microwave or radio bands.
Re: Atomic nucleus excited with laser: A breakthrough after decades
#174Earlier quoted context omitted.
Not a physicist, so I am asking out of curiosity and to learn: have the limitations to the precision of current atomic clocks posed any problems?
synchronization of compute across data centers is something I've used atomic clocks for, precision and cost are an issue.
Sounds interesting. If you don't mind me asking, what sort of computation requires synchronization across data centers? And why couldn't it be done with NTP?
Re: Atomic nucleus excited with laser: A breakthrough after decades
#175Is this of any value when it comes to nuclear energy creation?
Re: Atomic nucleus excited with laser: A breakthrough after decades
#176Earlier quoted context omitted.
The problem is that the planet could be hollow and produce the same gravitational measurements on the surface and outside. It needs to be coupled with a model that introduces constraints for the inverse problem to be defined.
Since mining is only concerned with material that's within maybe 0.1% of the distance from the surface to the core, seems like you'd just need to move the sensor around and make sure the signal changes about where you'd expect for a mass of X Kg at a depth of Y meters instead of a supermassive chunk of dense material much deeper. Or, to put it another way, build a grid map of the area and subtract any background sign…
Consider the special case of a spherical deposit. You can find the center and mass of the deposit, but not its volume or density.
But now that you know it is there, you can use other techniques, like seismic measurements, to nail that down.
Re: Atomic nucleus excited with laser: A breakthrough after decades
#177Earlier quoted context omitted.
The problem is that the planet could be hollow and produce the same gravitational measurements on the surface and outside. It needs to be coupled with a model that introduces constraints for the inverse problem to be defined.
Since mining is only concerned with material that's within maybe 0.1% of the distance from the surface to the core, seems like you'd just need to move the sensor around and make sure the signal changes about where you'd expect for a mass of X Kg at a depth of Y meters instead of a supermassive chunk of dense material much deeper. Or, to put it another way, build a grid map of the area and subtract any background sign…
In practice, that's what would happen. Move around until seeing some larger gravitational pull, likely indicating some deposit. However, formally, this is not correct due to the mere fact that the gravitational force is proportional to 1/R^2, just like a Columb force. Thus, there are infinite numbers of mass distributions that produce the exact same gravitational field on the surface. The planet could be hollow, and we would not know it only from the field measurements.
A practical constraint is mass density, which has maximum and minimum values. We can make a crude approximation that the planet's density is constant, evaluate the field on the surface from the planet's shape and compare it with measurement. This would be more useful, but still, it wouldn't tell us whether there is a combo of water reservoir and a large massive deposit below it.
Re: Atomic nucleus excited with laser: A breakthrough after decades
#178Earlier quoted context omitted.
I >think< that this will enable more accurate magnetometers (see OPM-MEG and atomic clock magnetometers). Which can be used, among other things, for measuring neuronal activity.
Can you explain your reply a bit; how will MEG tech evolve from this breakthrough?
I'm still reading the paper but I think it might enable better versions of this sort of thing: https://www.nist.gov/noac/technology/magnetic-and-electric-f...
Re: Atomic nucleus excited with laser: A breakthrough after decades
#179The way to know if a “breakthrough” could be legit is by observing the comment count of a post that says breakthrough
Re: Atomic nucleus excited with laser: A breakthrough after decades
#180Very cool. Probably impossible but I wonder if you could see non-linear nuclear effects if you hit it with enough intensity. Laser induced fission anyone?
Look up „hafnium controversy“: https://en.m.wikipedia.org/wiki/Hafnium_controversy