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Atomic nucleus excited with laser: A breakthrough after decades

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Re: Atomic nucleus excited with laser: A breakthrough after decades

#201

Post by sgt101 »

Dibby053 wrote: post #174
sgt101 wrote: post #41

Earlier quoted context omitted.

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?

Essentially distributed consistency and co-ordination. NTP isn't accurate/consistent enough because of light speed being limited. This matters for applications like network management and large scale control.

Re: Atomic nucleus excited with laser: A breakthrough after decades

#202

Post by snarkconjecture »

graycat wrote: post #64
greenbit wrote: post #52

Earlier quoted context omitted.

Probably just emits another photon of the exact same wavelength a short time later. The time would be probabilistic, like 50% chance of emission in X amount of time.

Physics does not emphasize this, but the half life concept essentially assumes a Poisson process (Cinlar, Stochastic Processes ) which has a Markov (past and future conditionally independent given the present, details from the Radon-Nikodym theorem, with a cute von Neumann polynomial proof, Rudin, Real and Complex Analysis ) assumption. The half life concept seems to be standard over much of physics. That a Markov as…

How so? Isn't the Markov property just a consequence of basic QM?

Re: Atomic nucleus excited with laser: A breakthrough after decades

#203

Post by bobmcnamara »

lifeisstillgood wrote: post #51

>>> For example, the Earth's gravitational field could be analyzed so precisely that it could provide indications of mineral resources Hold on how does that work? I have had a sort of sci-fi idea that sufficiently sensitive gravitational field measurements coukd detect the passing of submarines (I am not sure on the maths tbh) - which would render a lot of nuclear strategy moot. Just need to get a grasp on the maths

Does the average density of most submarines approaching the density of water make that more difficult?

Are you looking for density variation between the parts and airspaces of a submarine?

Re: Atomic nucleus excited with laser: A breakthrough after decades

#204

Post by nathan_compton »

denton-scratch wrote: post #122
emblaegh wrote: post #7

Earlier quoted context omitted.

Classical there is used in the sense of “non relativistic”.

I thought relativistic quantum physics was not a thing (yet).

The body of work called quantum field theory is a theory of relativistic quantum mechanics although many aspects of its foundations are difficult to pin down, its a very powerful and useful apparatus.

Re: Atomic nucleus excited with laser: A breakthrough after decades

#205

Post by nathan_compton »

snarkconjecture wrote: post #202
graycat wrote: post #64

Earlier quoted context omitted.

Physics does not emphasize this, but the half life concept essentially assumes a Poisson process (Cinlar, Stochastic Processes ) which has a Markov (past and future conditionally independent given the present, details from the Radon-Nikodym theorem, with a cute von Neumann polynomial proof, Rudin, Real and Complex Analysis ) assumption. The half life concept seems to be standard over much of physics. That a Markov as…

How so? Isn't the Markov property just a consequence of basic QM?

Some people probing the boundaries of QM look for correlations in rapidly repeated measurements in hopes of finding some non-random quality.

Re: Atomic nucleus excited with laser: A breakthrough after decades

#206

Post by j33zusjuice »

What impact could this have on the value of cesium? Some time ago, I remember reading about cesium’s importance to tech, particularly for atomic clocks. It was in an article about the potential discovery of a cesium mine that might have huge political impact because China owns most of the cesium mines. And I imagine being able to replace cesium entirely would have similar impact.

Re: Atomic nucleus excited with laser: A breakthrough after decades

#207

Post by preisschild »

tromp wrote: post #79
fsh wrote: post #5

The measurement was already confirmed by a different group: https://arxiv.org/abs/2404.12311 This is important since impurities in the crystals used lead to all kinds of fluorescence that could be mistaken for a signal from the Thorium ions. Now two groups have seen exactly the same signal in different Thorium-doped crystals which is very covincing that they have found the actual nuclear transition.

I find it satisfying to see a researcher called THORsten SchUMm devoting his research to THORiUM.

In a country where breeding and burning thorium to generate energy is illegal :/

Re: Atomic nucleus excited with laser: A breakthrough after decades

#208

Post by snarkconjecture »

bawana wrote: post #185
adrian_b wrote: post #97

Earlier quoted context omitted.

The radiation emitted when nuclei transition between their internal energy levels is known as gamma rays. The gamma rays normally have energies per photon many orders of magnitude greater than for visible light and also much greater than for X-rays (which are produced by electrons accelerated by very high voltages when hitting a target). The thorium 229 nucleus is the only one that can emit gamma rays that are so low…

Arent gamma, x, and uv ALL em radiation? What makes a gamma with a wavelength near uv still allow it to be called gamma? Why dont we say the nucleon emits uv at 148 when it transitions to its ground state?

You could say that as well. Gamma is often (usually?) defined as any radiation that originates from nuclear state transitions rather than electrons; this tends to be very high energy but can overlap the range of EM radiation from electronic transitions. Th229 is the extreme outlier.

Re: Atomic nucleus excited with laser: A breakthrough after decades

#209

Post by snarkconjecture »

nathan_compton wrote: post #205
snarkconjecture wrote: post #202

Earlier quoted context omitted.

How so? Isn't the Markov property just a consequence of basic QM?

Some people probing the boundaries of QM look for correlations in rapidly repeated measurements in hopes of finding some non-random quality.

That sounds like the opposite of what graycat was suggesting.
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