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Submission + - First Nuclear Clocks Start Ticking in Vienna and Beijing (phys.org)

Submitted by necro81
necro81 writes: Two groups, one in Vienna and one in Beijing, have successfully demonstrated the world's first nuclear clocks. Standard atomic clocks, like the caesium clocks that define the second, operate by observing the transition of electrons between different orbits about the nucleus. The resulting radiation is usually in the microwave range, and can produce clocks accurate to one second in 100 billion years.

Nuclear clocks go a step further, and probe energy transitions within the nucleus itself. Nuclei can arrange their protons and neutrons into different configurations, called isomers. The isomer with the lowest energy is the one usually found; higher-energy ones are only metastable and decay quickly. Usually it takes serious energy — x-rays and gamma rays — to excite a nucleus into a higher-energy arrangement. It so happens that thorium-229 can be excited using UV light with a wavelength of 148 nm — just within the capabilities of some exotic lasers.

It's still been quite a challenge. For one thing, Th-229 is not found in nature; it must be extracted from the decay chain of uranium-235. The Beijing team used just a microgram mixed in a crystal of calcium fluoride.

Although these prototype nuclear clocks are not yet more accurate than existing atomic clocks (one second in millions, rather than billions, of years), they show the way towards what may be possible. Because the energy transition is in the nucleus, rather than the electron cloud, it is less susceptible to outside disturbances like magnetic fields. And the fundamental frequency is much higher (five orders of magnitude), which should yield more precise timing. This development could lead to smaller and more reliable time standards across the world (and solar system).

Comment Re:The Ultimate Bike Shed (Score 1) 235

by eepok (#66366560) Attached to: Canadian Analysis: Permanent Daylight Saving Harms Sleep and Mental Health

It's the Parkinson's Law of Triviality: https://en.wikipedia.org/wiki/...

Basically, people simply accept the complex stuff from experts because they know they won't be able to understand it. However, they will waste ridiculous amounts of time on minutia because that's the stuff they personally can relate to. (Uh, ya, sure. Put in a nuclear power plant.... but I've painted things before and I have a strong opinion on the color of the bike shed!).

Comment Re:Fundamental physics has never been more dead (Score 4, Funny) 28

by Rei (#66366362) Attached to: Francis Halzen Wins Nobel Physics Prize For Antarctic 'Ghost Particle' Hunt

"Okay, nuclear power. Yeah. Yeah, they did give us that. That's true. "

"And industrial-scale superconducting magnets!"

"Don't forget GPS satellite relativistic corrections!"

"And radioisotope therapy!"

"Electron beam therapy?"

"World Wide Web, wasn't that created by particle physicists?"

"Yeah, they did do that."

"Capacitative touchscreens too, you know."

"All right, all right, FAIR ENOUGH! But APART from computers, telecommunications, nuclear power, PET scans, MRIs, satellite communications, superconductors, radioisotope therapy, electron beam therapy, heat-shrink tubing, cargo and baggage screening, smoke detectors, muon tomography, capacitative touchscreens, and the World Wide Web, WHAT HAS PARTICLE PHYSICS EVER DONE FOR US?!"

"Synchrotron light sources for drug discovery?"

"Oh, drug discovery?! GROW UP!"

Comment Re:Very funny (Score 1) 72

by Rei (#66366174) Attached to: OpenAI Is Adding Text Watermarking In ChatGPT and Codex

if this were true it would not be possible for the system to read the watermark.

You confuse "invisible to humans" with "invisible to statistical analysis". Humans can't, for example, see the difference between metameric colours. Statistical analysis can. Humans can't see minor drift at scales where Brownian motion dominates. Statistical analysis can. Humans can't see the difference between background disease rates and new rising threats. Statistical analysis can. On and on. Statistical analysis is a far more powerful tool than human perceptual abilities.

this is also a lie. Identical thoughts must be expressed identically, otherwise they are, in fact, *different* thoughts.

I literally gave an example above. If you saw "picked a mango", "selected and picked a mango", "from within the tree, picked a mango", you would never think there was anything going on in the choice, and it isn't going to change the story one iota.

Comment Re:Meanwhile, back at the benchmarks (Score 3, Interesting) 25

It actually makes RAM needs worse than a dense model, for a given quality.

That said, inference techniques like FreeToken are improving MoE swapping performance, so it's not as bad as it once was. Honestly, I would not be at all surprised if we start doing training in a swap-aware manner, where expert cache misses count as loss and models can queue experts to start loading before they're needed. Could even train in two tiers of loading - RAM and disk. Wouldn't that be great? Could run multi-terabyte models on consumer hardware. Training would tend to tend to concentrate key logic and reasoning on small number of very active experts, mixed reasoning/knowledge on less common experts that are usually kept in RAM, and rarer knowledge on experts that usually remain on-disk until needed.

Comment Re: Meanwhile, back at the benchmarks (Score 2) 25

There are well known, reputable abliterators on HuggingFace.

Also, censorship usually (not always) is something you care about for chats, not agentic work.

A .safetensors or .gguf model cannot run code unless you let it. No agentic framework = all it can do is write text. It can't hurt you directly. At worst, it can only lie to you.

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