Can it factor 21?
Just gonna leave this here: Why haven't quantum computers factored 21 yet?
https://algassert.com/post/2500
Willow quantum chip demonstrates verifiable quantum advantage on hardware
231–240 of 281 posts
Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware
#232Earlier quoted context omitted.
I think that’s backwards: most of the stuff you mentioned is using TLS and can switch to post-quantum algorithms with a config change, and do so incrementally with no user-visible impact - e.g. right now I’m already using PQC for many sites and about half of the traffic Cloudflare sees is using PQC: https://radar.cloudflare.com/adoption-and-usage In contrast, cryptocurrencies have to upgrade the entire network all at…
> In contrast, cryptocurrencies have to upgrade the entire network all at once or it’s effectively a painful fork Bitcoin is much more centralized than the popular imagination would have you believe, both in terms of the small number of controlling interests behind the majority of the transaction capacity, and just as importantly the shared open source software running those nodes. Moreover, the economic incentives f…
(I know that you understand this, but just highlighting it)
In fairness, the original Bitcoin white paper referenced both (1) distributed compute and (2) the self-defeating nature of a Byzantine attack as the means of protection. It's not as though (2) is just lucky happenstance.
Hence, why proof of stake can exist.
Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware
#233Earlier quoted context omitted.
To me, it matters because it's a sign that it might not be particularly transferable as a method of computation. A wind tunnel is a great tool for solving aerodynamics and fluid flow problems, more efficiently than a typical computer. But we don't call it a wind-computer, because it's not a useful tool outside of that narrow domain. The promise of quantum computing is that it can solve useful problems outside the qua…
Good point, I guess that's why I find this comments section boring and not representative of the HN I've known for 16 years: there's a sort of half-remembering it wasn't powerful enough to do something plainly and obviously useful yesterday. Then, we ignore today, and launder that into a gish-gallop of free-association, torturing the meaning of words to shoehorn in the idea that all the science has it wrong and inter…
I know what you're talking about, but I think you happened to pick a bad example to pick on here. This wind tunnel analogy resembles a common criticism of the prior experiments that were done by Google and others over the last few years. Those experiments ran highly unstructured, arbitrary circuits that don't compute anything useful. They hardly resembled the kind of results that you would expect from a general purpose, programmable computer. It's a valid criticism, and it seems like the above commenter came to this conclusion on their own.
To that comment, the present result is a step up from these older experiments in that they a) Run a more structured circuit b) Use the device to compute something reproducible (as opposed to sampling randomly from a certain probability distribution) c) The circuits go toward simulating a physical system of real-world relevance to chemistry.
Now you might say that even c) is just a quantum computer simulating another quantum thing. All I'll say is that if you would only be convinced by a quantum computer factoring a large number, don't hold your breath: https://algassert.com/post/2500
Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware
#234Earlier quoted context omitted.
I haven't once even thought of investing in crypto, and think that the technology is mostly useless and proof of work schemes should be banned on environmental grounds. Even so, I don't agree that quantum is a threat to crypto. There are already well known quantum-resistant encryption schemes being deployed live in browsers, today. Crypto can just start adopting one of these schemes today, and we're still probably de…
>There are already well known quantum-resistant encryption schemes being deployed live in browsers, today. Crypto can just start adopting one of these schemes today, and we're still probably decades away from a QC that can factor the kinds of primes that crypto security uses. It's very strange that some people act like switching over to a post quantum cryptography scheme is trivial. Did you watch the video I replied…
Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware
#235Earlier quoted context omitted.
At least they claim that: «Quantum verifiability means the result can be repeated on our quantum computer — or any other of the same caliber — to get the same answer, confirming the result. This repeatable, beyond-classical computation is the basis for scalable verification.» (emph. mine) But apparently they haven't demonstrated the actual portability between two different quantum computers.
What’s the difference between the claim that they’re making and what you say they haven’t done?
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Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware
#236the big problem with quantum advantage is that quantum computing is inherently error-prone and stochastic, but then they compare to classical methods that are exact let a classical computer use an error prone stochastic method and it still blows the doors off of qc this is a false comparison
Stochasticity (randomness) is pervasively used in classical algorithms that one compares to. That is nothing new and has always been part of comparisons. "Error prone" hardware is not "a stochastic resource". Error prone hardware does not provide any value to computation.
Yes the claims here allow the classical computer to use a random number generator.
Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware
#237Why use the subtext? In the peer review (pp30-31), the authors > acknowledge [that] Hamiltonian learning of an actual physical system has not been performed [and] have therefore further de-emphasized the quantum advantage claim in the revised manuscript https://static-content.springer.com/esm/art%3A10.1038%2Fs415...
This excerpt misses the wider point of the paper. The paragraph immediately following the one you quote still does make claims of quantum advantage: "Our second order OTOC circuits introduce a minimal structure while remaining sufficiently generic that circumvents this challenge by exploiting the exponential advantage provided by including time inversion in the measurement protocol, see arXiv:2407.07754." The advanta…
Shor’s algorithm’s advantage isn’t proven, but a proof that integer factorization doesn’t admit a classical algorithm faster than O((log N)^3) could be found. The same applies for Google’s artificial problem.
Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware
#238I would be quite worried about advances in quantum computers if I had any Bitcoin after watching this DEFCON talk: https://www.youtube.com/watch?v=OkVYJx1iLNs
The quantum algorithm that would break certain kinds of public key cryptography schemes (not even the core part of Bitcoin blockchains, which are not vulnerable to quantum computers) will take days to weeks to break a single key [0]. This is another reason why we will have plenty of warning before quantum computing causes any major disruptions to daily life. What I would start worrying about is the security of things…
> not even the core part of Bitcoin blockchains, which are not vulnerable to quantum computers
Um, what? Shor’s algorithm can take the public key of a wallet (present on any outgoing transaction in the ledger) and produce its private key. So now you can hijack any wallet that has transferred any Bitcoin. Notably only one successful run of the algorithm is needed per wallet, so you could just pick a big one if it takes weeks.
It probably wouldn’t help you mine in practice, sure. Technically it would give you better asymptotic mining performance (via Grover’s algorithm) but almost certainly worse in practice for the foreseeable future.
Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware
#239I think that quantum will be the next bubble
100%. I'm buying all the domain names and have already profited heavily over 9 months.
Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware
#240the quantum chip iirc only runs a subset of algorithms due to limited gates implementable on the quantum chip; is the quantum chip a universal computer?
This is more the case for D-Wave's machines which are specialised for quantum annealing, allowing for greater numbers of qubits. Google and most other major hardware players make chips which can implement a universal quantum gate set allowing for arbitrary quantum operations to be performed (in principle). The issue with these chips is that quantum error correction is not fully implemented yet so computations are effectively time-limited due to the build up of noise from imperfect implementation and finite-temperature effects. A big part of current punts at quantum advantage is figuring out how to squeeze every last drop out of these currently faulty devices.