Amazon: Diamonds are a quantum network's best friend

The secret to unlocking the full potential of quantum networking may be hiding at the center of a diamond, according to Amazon Web Services. This week, AWS popped the question to De Beers subsidiary Element Six in the hope of finding it. One of the early applications of quantum networks is key distribution, which uses a pair …

[Snowy]

De Beers to supply quality – flawed – rocks

They have loads of flawless ones laying about, diamonds are not rare, just the supply is restricted.

[DS999]

Re: De Beers to supply quality – flawed – rocks

So that means they probably have a couple orders of magnitude more flawed diamonds stockpiled.

[Crypto Monad]

I am missing something very fundamental here.

When we're talking about optical losses along a fibre optic path, I imagine those are due to photons being absorbed or scattered, so the number of photons reduces over distance.

However, for this quantum entanglement stuff, we're talking about *individual* photons (one of an entangled pair), right?

Now, if a photon arrives at one of these repeaters, and is re-sent as a fresh photon, surely it's still just a photon? Is this new photon any more likely to get absorbed in the next 10km (say) than the original one was? Do photons carry a memory of how long they have been travelling, and therefore get "tired" and need to be replaced by a "fresh" photon every so often?

Alternatively, I can imagine that instead of single photons, bursts of photons with some sort of similar entanglement are sent, and over distance the numbers will go down as they are absorbed. But in that case, wouldn't the repeater need to replace one incoming photon with two or more identical outgoing photons, in order to make the numbers back up again?

[Anonymous Coward]

$%&@, it went dark again!

The details related in the article _are_ less than reassuring. My impression after reading it was "so... fusion will work before this?"

[I am David Jones]

Actually, I believe the main problem is the spreading of the pulse.

You start with a well defined pulse of light that is easy to detect. This contains a large range of frequencies.

As it travels down the fibre, the effect of the refractive index of the fibre depends on the frequency. So the different frequencies spread out and the pulse becomes a smear which is harder, and eventually impossible, to detect.

This is direct from old memory so apologies for any mistakes.

Just don’t ask me how this relates to entangled pairs…

[VonGell]

Nonsense! Superposition can be achieved based on the used, for instance, by OpenAI Artificial Intelligence technology, for a negligible fraction of what it would require to develop this mythical 'quantum computer'. Indeed, the OpenAI technology requires the establishment of the importance (i.e., weights) of each text phrase, where these weights are almost always irrational numbers, which must be rounded to rational or natural. There you have the desired superposition.

Forget about idiotic “quantum computers” for trillions! The problem is solved for pennies long time ago.

[Michael Wojcik]

Kookery of the Week right here. Even better than your usual efforts, Ilya.

There are a zillion papers, blog posts, etc freely available discussing Quantum Key Agreement and the issues with extending it over long distances, if anyone's actually interested in the technical details. Schneier did a writeup on the most common scheme some years back on his blog, for example. And people have been working on diamond semiconductors and optics for decades. It's not clear to me what, if anything, is new here. Maybe De Beers trying to extend their domination into the industrial-diamond market.

I really wish that back in the '80s GE had just told them to go fuck off and started producing gem-quality diamonds. Bring the whole damn diamond-jewelry industry down. It's hard to see how everyone outside the cartel wouldn't have been better off for it.

[VonGell]

Neither diamonds nor other super-duper technological difficulties are needed. There is no need in hundreds of billions and trillions. OpenAI has already practically created and exploit a quantum computer, although in this case it is a by-product.