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Willow quantum chip demonstrates verifiable quantum advantage on hardware

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Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware

#241

Post by gsf_emergency_4 »

johncolanduoni wrote: post #237
qnleigh wrote: post #230

Earlier quoted context omitted.

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.

An analogy which is closer to Google's experiment: measuring versus calculating the energy gaps in benzene to an arbitrary accuracy.

It is "verifiably" faster to measure those with state of the art "quantum tools" but that does not improve our understanding of other aromatic molecules.

(we may still get some insights about anthracene however)

The googles' advantage can be satisfactorily summarised as "not having to write the problem (ie off-diagonal terms) in terms of a classical basis" -- there is a severe overhead of having to represent qubits as bits.

Still, I suspect that that 13000x came from not putting in effort to implement the aforementioned "minimal structure" in their classical counterparts. They emphasized "echoes" and "ergodicity" & I think the "quantum" can further be dropped :)

In general, I do believe that whatever "informational advantage" we can get from these experiments should likewise be used to improve classical calculations.

As another eg: In the arxiv paper linked by GP they talk about provably-efficient shallow classical shadows

Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware

#243

Post by portaouflop »

jeffhuys wrote: post #139
portaouflop wrote: post #125

Earlier quoted context omitted.

So actually it’s neither verifiable or repeatable in any real-works definition of the words.

This is your second comment in this thread (as far as I’ve scrolled) saying this without an explanation. Could you elaborate on why?

Quantum computing is mostly a scheme to get more grants/funding for quantum research, it doesn’t have any real world application and most likely won’t have any in the foreseeable future. Like verifiable means i can run 3x3 on any quantum computer and always get 9 as result - but quantum computers cant even do that. Don’t get me wrong; it’s very cool theoretical research, and more power to the scientist. But thinking it will have any impact on the real world in our lifetime is a pipe dream imho

Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware

#244

Post by janpmz »

XiphiasX wrote: post #242

Genuine question - why is Bitcoin not collapsing upon this news? Surely big money that control Bitcoin have high enough IQ to extrapolate inti the future and come to decision on the inevitable implications.

The critics claim the noise collapses quantum states so quickly that it's not possible to make full use of the quantum effects. The burden of proof is on the chip makers. I think they have not convinced the critics yet.

Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware

#245

Post by flawn »

vayup wrote: post #222
irjustin wrote: post #218

Earlier quoted context omitted.

> Everything would be broken. Think banks, brokerage accounts, email, text messages - everything. Wonder if this would become the next "nuclear proliferation". Since it's so hard to manufacture it gets controlled at state level and then becomes a technology that the general public are never allowed to have.

No, it is a known problem. It will get fixed in time.

That based on the assumption that we don't have any quantum breakthroughs

Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware

#246

Post by khaki54 »

XiphiasX wrote: post #242

Genuine question - why is Bitcoin not collapsing upon this news? Surely big money that control Bitcoin have high enough IQ to extrapolate inti the future and come to decision on the inevitable implications.

Because to steal bitcoin by reverse engineering a private key from a public one you need to be able to factor a very large number. Currently the highest number they have factored using only quantum computing is 21.

Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware

#247

Post by akimbostrawman »

iwontberude wrote: post #78
andrewla wrote: post #61

Earlier quoted context omitted.

How could updating the software possibly make a difference here? If the encryption is cracked, then who is to say who owns which Bitcoin? As soon as I try to transfer any coin that I own, I expose my public key, your "Quantum Computer" cracks it, and you offer a competing transaction with a higher fee to send the Bitcoin to your slush fund. No amount of software fixes can update this. In theory once an attack becomes…

As you alluded to, network can have two parallel chains where wallets can be upgraded by users asynchronously before PQC is “needed” (a long way away still) which will leave some wallets vulnerable and others safe. It’s not that herculean as most wallets (not most BTC) are in exchanges. The whales will be sufficiently motivated to switch and everyone else it will happen in the background. A nice benefit is it solves…

>Satoshi’s wallet becomes the defacto quantum advantage prize. That’s a lot of scratch for a research lab.

Considering that would be criminal theft I doubt it. Moving the funds could also lead to panic crash, selling them off would not only take ages but involve doxing yourself and put a billion dollar bounty on your head because transaction are public and off ramps all use KYC.

It would be much safer to slowly crack old small value wallets over time.

Reminder that actual good cryptocurrency like monero have the advantage of wallets and transactions being private so you would need to crack without even knowing if they are worth it or exist.

Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware

#248

Post by acdha »

__MatrixMan__ wrote: post #212
acdha wrote: post #191

Earlier 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…

I can't remember which chain it was but I'm sure I've seen stats on in-progress rollouts of protocol changes where the network took something like weeks or months to all get upgraded to the new version. You can design for tolerating both for a time.

Yes - definitely not impossible, just something which requires coordinated deployment as opposed something the two parties to a connection can do themselves.

Re: Willow quantum chip demonstrates verifiable quantum advantage on hardware

#249

Post by tsimionescu »

IAmGraydon wrote: post #194
tsimionescu wrote: post #187

Earlier 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…

I hadn't watched the video, but I cam away even more confused by your comment. The video, while very alarmist about the threat of QC, is also very explicit that switching to PQE is very easy. The whole point of the talk is "switching is easy, the costs are huge, start doing it today".

I also think the talk vastly overestimates the urgency of this, based on little more than marketing projections. The reality is that many of those claims are hugely optimistic, and ignore some fundamental difficulties. Mainly, the qubits / quantum gates being produced today are not at all as programmable as the logical qubits used in the theoretical results presented in those papers. So, even if they do achieve the projected marketing numbers, it's likely that they won't be able to run Shor's or Grover's algorithm on those QCs.

Not to mention, we've had many periods of flimsy encryption being used for important infrastructure, and it has not resulted in wide scale disasters. Of course we should be responsible and avoid this, but I think the doomsday scenario suggested is way overblown, even if it were true that a 1500 logical qbit programmable QC would be available in 2030.

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