This bit sounds very Quantum.
None of the documents express certainty that quantum machines will revolutionize the fields they consider.
The US Defense Advanced Research Projects Agency has published the results of an exercise that assessed whether quantum computers will deliver on the promise of solving problems that stump classical machines – with mixed results. In 2021 DARPA created a Quantum Benchmarking program "with the goal of reinventing the metrics …
strong SEP field
Fields usually have associated particles so I have to wonder what SEP fields pop out of the void? Bogons, nimbytrons, karens...?
I imagine the infinite improbability drive worked by a clever QC determining the exact momentum of The Heart of Gold so that the ship's position was pretty much both everywhere and nowhere but with the careful and controlled lessening of the QC's momentumal dogmatism the ship might eventually come to be somewhere and hopefully mostly the same place.
> Errrmmm ... and where might your towel be then, sir?
You're showing your age .. Answer To The Ultimate Question.
42? Well ... yes ... but also 40,41,43,44,109,1044,1492,1235468923473,-17,3.14259,16i ... and too many more to list. And also, so far as I can tell none of that has been confirmed on actual running hardware.
But if they ever build one that works it'll apparently be able to do super fast Fourier transforms. I suppose that's something. Can blockchain or LLMs do that?
CFD is the hoped for quantum computing solution for fusion power generation.
When DARPA writes: "future quantum computers are unlikely to provide utility for incompressible CFD applications unless significant algorithmic advancements or alternative quantum approaches are developed.", that translates as "quantum computers won't solve nuclear fusion".
Err, when DARPA write "incompressible CFD" that means the easy stuff - with fluids like water whose compressibility can be ignored.
The fluid in a nuclear fusion reactor is very, very, compressible which makes the fluid dynamics much harder. Not only that, it is a plasma, so the particles are all charged, and if you have moving charged particles you need to consider magnetism. There are people who try and model magneto-hydro-dynamics, but it's ... not easy.
Of course, that doesn't nullify your conclusion "quantum computers won't solve nuclear fusion" - if they can't do the easy stuff, what hope have they got with the really messy stuff?
Quantum computing is here now. No reputable authority doubts the Google QC demonstrations, for example.
Whether (general) QC supremacy is here is still up for debate, though a number of reasonable experts believe it is, and others are not ready to say it isn't.
Useful QC, for most definitions of "useful" (i.e., excluding things like "experimenting to see how various QC architectures work"), is not yet here, at least as far as anything that's been made public. (And I'm not one of the foil-hat types who believes the NSA has massive quantum computers they built with alien technology from Roswell or something; I think the probability of secret useful-size-and-reliability QC machines existing now is low.) And it may be a long time coming.
That said, this looks like a useful exercise from DARPA. Anyone who actually pays any attention to QC already knew that physical simulation was one of the main areas of interest, but it's good to try to pin down what is and isn't likely to be tractable with moderate-size quantum machines, NISQy or otherwise.
I read that whole article on the assessment of feasibility of quantum computing and I came away with something I found quite profound.
The plural of 'axis' really is 'axes'.
I did not know that.
Oh and some quantum computing shit I can't even begin to wrap my alcohol withered brain around.
The quantum-computing shit boils down to: sufficiently-large-and-accurate quantum computers will probably be helpful for these sorts of physics and chemistry simulations, and not so helpful for those sorts.
Which is not surprising, but the goal here was to figure out some of the things that go in which of the two bins. And thus doth science proceed.
People are doing the same with autoregressive deep-learning and diffusion models ("AI").^{1,2} It's an important exercise. You get new tech, you find out what it's good for.
^{1}Interesting piece today, by-the-by, on LessWrong about whether AlphaFold 3 actually beats AutoDock Vina. It's by the guy who apparently created the latter, so take it with a grain of salt, but he makes good points.
^{2}Legendary chemistry-blogger Derek Lowe has some posts about LLMs and chemistry that are worth reading.
....there's no mention of cryptography or the interest of the good folk at Fort Meade.
Yup......very strange! Of course, if you know the velocity of Fort Meade (zero), then the actual position is unknown....might be in Cheltenham!!
Then there's Schroedinger's Paradox about the snoop in a box!! Alive or dead? All very confusing!!
@FrogsAndChips
Wikipedia: "Shor's algorithm is a quantum algorithm for finding the prime factors of an integer"
You may be talking about THIS PARTICULAR aspect of things which "could break current crypto".
But not all "crypto" is founded on large prime numbers:
(1) One time pads
(2) Book ciphers
(3) Elliptical curve mathematics
.......to name only three.
Yup.....still a puzzle that Fort Meade isn't in the mix pondering about snooping and quantum computers!!
.....but maybe they are!!
But not all "crypto" is founded on large prime numbers:
Reversing Elliptic Curve encryption uses the "elliptic curve discrete logarithm function" rather than factorization, but the algorithm itself is defined by picking a prime number as a maximum, a curve equation and a public point on the curve.
Right. And we already have variants of Shor's for breaking finite-field DH (I think that's in Shor's original paper, in fact) and for breaking ECC.
And we already know that Grover's algorithm offers a square-root (that is, exponent of 0.5) improvement in work factor for brute-forcing symmetric keys, and that no quantum algorithm can have better time complexity than that for unstructured search. Since even if your quantum gates are as fast as the best classical ones^{1} and there's no classical pre- and post-processing time required^{2} defenders only have to double their key lengths to have the same strength against your QC unicorn as they do against a classical system, that Really Doesn't Matter.
There conceivably could be algorithms which 1) break a given symmetric algorithm (or some other cryptosystem of interest) faster than unstructured search, 2) are in BQP, and 3) are feasible to implement. But if anyone's found one yet, they haven't said, to the best of my knowledge.
We could assume the NSA is in possession of such legendary algorithms. We could assume all sorts of things. But even if they are, and even if they have a QC that's better than anything which has been made public,^{3} it's enormously unlikely that they have the resources to use it to break cryptography at scale. It would only be feasible to break a relative handful of very high-value targets. And usually there's some better way of breaking a few high-value targets.
^{1}They're not.
^{2}There is.
^{3}They don't.
The "more positive" nuclear magnetic resonance (NMR) spectroscopy article is great news IMHO. Apparently, the boffins could apply a nonunitary Hamiltonian Quantum Eigenvalue Transform (QET), with Controlled-Z gate, to that Quantum Signal Processing (QSP) challenge, with fields far below geomagnetic strengths. This could usher in an era of highly portable tri-corder tech, even without Casanova magnets!
"How to get politicians to understand science and scientists?"
And Quantum Computers will probably do nothing to solve that problem.
I'll get my coat, it's the one with the Feynman lectures on Physics in the pockets.
Edit: Sorry, bad tome at the moment what with the General Election in the UK and the usual 'denials of reality' from politicos hoping to get elected.
Oh, they'll break some RSA, DH, and ECDH keys, because that's a really nice demo of the system working. If and when anyone gets a general-purpose machine with thousands of error-correcting qubits up and running, that's one of the easiest ways to prove it works and that you have quantum supremacy (or "quantum advantage" or whatever term you prefer).
But as a practical matter, yeah, breaking asymmetric-cipher keys is going to be pretty low on anyone's list. Just not interesting except for the small fraction of high-value targets.
The link to the papers contains this invitation https://www.darpa.mil/work-with-us/ from the land of quantum unicorns and rainbows.
I always took the view that the world was more than capable of destroying itself without my feeble assistance.
Possibly more interesting are problems in chemistry and biochemistry that are currently accessible to conventional computing but could be significantly faster or scaled up with QC. If QC could do some of the heavy lifting in custom enzyme design or lead to understanding photosynthesis to the point of being able to construct artificial photosystems tailored for particular uses, then the benefits for the environment, and generally, could be far reaching.
Although just taking the crypto bros and the AI snake oil purveyors down to the basement would also do the planet a power of good.
problems in chemistry and biochemistry
Note the Amyloid-Beta paper mentioned at the end of the article. Pre-print isn't available yet, and I'm not qualified to evaluate it anyway, but that's a biochem one and the title suggests it's relevant to Alzheimer's. Maybe Derek Lowe will write about it once it's available; he's worked in that area.