[HN Gopher] The case against Google's claims of "quantum supremacy"
___________________________________________________________________
The case against Google's claims of "quantum supremacy"
Author : nsoonhui
Score : 157 points
Date : 2024-12-11 04:22 UTC (18 hours ago)
(HTM) web link (gilkalai.wordpress.com)
(TXT) w3m dump (gilkalai.wordpress.com)
| gnabgib wrote:
| Strange timing given the claim was in 2019, guess this post was
| generated because of Willow.
|
| _Google claims to have proved its supremacy with new quantum
| computer_ (256 points, 1 year ago, 229 comments)
| https://news.ycombinator.com/item?id=36567839
|
| _Quantum computers: amazing progress, but probably false
| supremacy claims_ (126 points, 5 years ago, 73 comments)
| https://news.ycombinator.com/item?id=21167368
|
| _Google Achieves Quantum Supremacy. Is Encryption Safe?_ (38
| points, 5 years ago, 21 comments)
| https://news.ycombinator.com/item?id=21100983
|
| _Google claims to have reached quantum supremacy_ (114 points, 5
| years ago, 21 comments)
| https://news.ycombinator.com/item?id=21029598
|
| _Google Engineers Think This 72-Qubit Processor Can Achieve
| Quantum Supremacy_ (91 points, 7 years ago, 42 comments)
| https://news.ycombinator.com/item?id=16543876
|
| _Google plans to reach a Quantum Computing milestone before the
| year is out_ (147 points, 8 years ago, 49 comments)
| https://news.ycombinator.com/item?id=14171992
| bawolff wrote:
| They added a paragraph at the end to address the new
| experiment.
|
| Still nothing really new here. I'm doubtful anything will
| convince the author short of shor's algorithm actually
| factoring large numbers.
| thesz wrote:
| https://eprint.iacr.org/2015/1018.pdf As
| pointed out in [57], there has never been a genuine
| implementation of Shor's algorithm. The only numbers ever to
| have been factored by that type of algorithm are 15 and 21,
| and those factorizations used a simplified version of Shor's
| algorithm that requires one to know the factorization in
| advance.
| adastra22 wrote:
| What's the point of quoting this?
| thesz wrote:
| To me it was eye opening on how skewed is the
| presentation of these quantum computing number factoring
| advances.
|
| It is completely in line of the "The Case Against..."
| adastra22 wrote:
| No one is claiming number factoring advances. That would
| require much longer lived qubits entanglement than is
| currently possible. The tech is clearly advancing forward
| though.
| bawolff wrote:
| That feels like a straw man. Nobody was claiming
| otherwise.
| rcxdude wrote:
| It feels more like the time to develop the tech has
| outlived the hype cycle around the tech, perhaps moreso
| than usual. That doesn't mean it isn't going anywhere,
| just that it's still slow (and in fact, after the hype
| cycle, the average press release is more likely to be
| substantive than during it, even if it's still
| incremental).
|
| (From my reading/understanding of it, for a while there's
| been little point in trying to make a quantum computer
| big enough to do such work, because the individual parts
| would not work well enough for it to have any chance of
| success, while this result primarily is showing that
| they're now at the cusp of the predicted tipping point
| where the qubits have a low enough error rate that
| building a larger system out of them has a hope of
| working. That's the big news in google's recent
| announcement, not them pushing up the numbers in this
| somewhat contrived benchmark)
| sampo wrote:
| > What's the point of quoting this?
|
| To remind us of the large difference between the public
| image vs the reality of quantum computing.
|
| Expectation: From the news, people are getting a feeling
| that quantum computing revolution is almost behind the
| corner, and current cryptosystems will soon become
| irrelevant. People are (here, in Hacker News) asking "is
| our society ready for this", "what could I do if I had
| this chip at home", "existing cryptography technology is
| in danger", "is it time to 100x key length on browsers".
|
| Reality: Using Shor's algorithm to factor 15 = 5x3 is
| still far beyond the reach of current quantum computers.
| We can factor 15 = 5x3 and even 21 = 7x3 if we cheat by
| eliminating those branches from the calculation that are
| not on the happy path the correct answer.
| jppittma wrote:
| What are the chances that the CIA has a manhattan project
| style quantum computer somewhere? I can't believe that if
| the current SOTA could break commonly used encryption
| methods that it would be widely known.
| GTP wrote:
| I think it's still unlikely. In the case of the Manhattan
| project, the USA government wasn't racing against private
| companies but against other governments. Therefore, all
| advances in the field where highly secret. In this case,
| the CIA would be racing against private companies as
| well, which are hiring the best physicists and engineers
| too. So, while it's possible that a governmental agency
| is ahead of what it is publicly know, I doubt that they
| would be _dramatically_ ahead. This is similar to part of
| the argument I would present if someone asks me why I
| believe cryptography in general is secure.
| zelon88 wrote:
| > In this case, the CIA would be racing against private
| companies as well...
|
| You mean like Skunkworks when they designed the SR-71?
|
| Or DARPA with Atlas?
|
| Or the DoD with the global GPS network?
|
| Or the NSA's ANT catalogue?
|
| Yeah, the government has never had any issues outpacing
| the private sector. You only ever find out about it when
| they want you to. Usually that happens 5 to 30 years
| after the market has already caught up.
| XorNot wrote:
| All your examples consist of things no company has any
| commercial incentive to do.
|
| Airlines don't want high altitude supersonic spy planes,
| for example.
|
| And GPS is a collective action problem: no one wants to
| pay for it, but we do all benefit from it being ambiently
| around.
| fidotron wrote:
| It is basically a certainty that the CIA and NSA have
| their own projects, and also keep very close tabs on
| those outside - it is their exact remit.
|
| The great quantum computing nightmare, from the NSA point
| of view, is someone sidestepping out of nowhere with a
| viable machine that works in an unexpected and easy to
| reproduce way.
|
| Edit to add: see also
| https://en.m.wikipedia.org/wiki/DNA_computing which while
| bounded in the same sense as conventional machines would
| still be a game changer.
| Der_Einzige wrote:
| For similar reasons, if you do anything interesting in
| AI, you're very much the type to be targeted with
| additional targeted surveillance.
|
| It's sad to imagine the amount of smart nerds out there
| whose only actual experience with women is from the fking
| honeypots that Langley or ft mead et al use to make sure
| that some prospective AI talent on discord isn't about to
| release a bioweapon. Clearly a lot of AI talent overlaps
| with incels and adjacent communities (see civit.ai as an
| example of this), It's common knowledge that field agents
| skew female since they're less suspected by patriarchal
| idiotic targets (they tout this in recruiting for DEI
| reasons). It's probably smart for AI startups to tell
| their male coworkers to be on the lookout for random
| attractive women trying to talk to you. The US military
| and foreign service et al specifically warns its members
| about this and it is a clear and present danger.
|
| And FYI, if the glowies aren't doing this, they're not
| doing their jobs, since the risk of some crazy open
| source AI person deciding to lone wolf society is rather
| high, at least according to the less wrong folks (that
| community I bet is also crawling with spooks). AI is so
| full of industrial and business espionage that I get
| scared just being in the space.
|
| I know this is happening too because the private version
| of it, expert networks, are extraordinarily lucrative and
| rely on basically laundering of material non public
| information with plausible deniability. The "experts" on
| an "expert network" are basically private business
| spooks, ackin to a private investigator targeting a
| business.
| dekhn wrote:
| I saw a lecture from the author of the first DNA
| computing paper (
| https://en.wikipedia.org/wiki/Leonard_Adleman) in '94. We
| pulled him into a room after the talk (because he was
| talking about scaling up the computation significantly)
| and walked him through the calculations. BEcause the
| system he designed required a great deal of DNA to
| randomly bind to other DNA in a highly parallel fashion,
| you'd need enormous vats of liquid being rapidly stirred.
|
| Like other alternate forms of computing, the systems we
| build on CPUs today are truly hard to beat, partly
| because people are trained on those systems, partly
| becaus the high performance libraries are there, and
| partly because the vendors got good at make stupid codes
| run stupid fast.
|
| At this point I cannot see any specific QC that could be
| used repeatedly for productive work (material
| simulations, protein design) that would be more useful
| than a collection of entirely conventional computing (IE,
| a cluster with 20K CPUs, 10K GPUs, 100PB of storage, and
| a fast interconnect). Every time I see one of these "BMW
| is using a quantum computer to optimize logistics" and
| look more closely, it's obvious it's a PR toy problem,
| not something giving them a business edge.
| naasking wrote:
| > What are the chances that the CIA has a manhattan
| project style quantum computer somewhere?
|
| Possible, but I think zero chance they have anything more
| practical than Google Willow, which is itself completely
| impractical for anything except quantum computing
| research.
| dekhn wrote:
| The NSA maintains a fleet of oddball devices that give
| them unique capabilities. Usually these are built by big
| vendors, but sometimes by smaller companies with a unique
| feature (IBM Harvest, Connection Machine CM-5, Cray
| Various Models of *MP) It seems reasonable they have some
| small number of quantum computers that a limited number
| of researchers use to explore new ideas, but it's harder
| to imagine their production operations use QM for
| cryptologic or other computing.
|
| One of their big needs for production operations is
| having 24/7 support through christmas break, which favors
| companies like IBM.
| adastra22 wrote:
| It is just around the corner though! We're not able to
| make long lived qubits able to survive multiple gate
| operations necessary for Shor's algorithm. But the issue
| here is error rates and decoherence time, and these
| decreasing at a geometric rate. We are getting very close
| to the tipping point enabling practical crypto breaks.
| fluoridation wrote:
| That reminds me of when galvanic batteries were
| discovered, and it was thought that the corrosion on the
| electrodes was something that could be worked on and
| eliminated. If you don't have a prototype that
| demonstrates all the properties that you're trying to
| develop, you have not demonstrated the viability of the
| technology. It could be that it's possible to achieve
| those properties with a little more work, or that a
| device that combines all of those properties
| simultaneously is simply impossible.
| drpossum wrote:
| A big part of all these discussions is "why should you trust
| any computational result you can't verify?"
| evandrofisico wrote:
| A big problem in science in general is reproducibility.
| There are thousands of papers being published every month
| with peer review, which prunes out the most obvious errors,
| but the whole system is built on trust.
|
| Very few labs around the world are tasked with testing
| results instead of trying to produce new science, and in
| this specific case, only google has access to the device
| being built and the computation tested by them impossible
| to verify with classic computers, unlike Shor's algorithm
| which is trivial to test with known primes.
| bawolff wrote:
| Because you can verify it part of the way there.
|
| The point is to ensure that researchers are actually doing
| what they think they are doing and not deluding themselves.
| Its not meant to prevent outright fraud.
| thesz wrote:
| Yes, it contains "I) Update (Dec. 10): The Wind in the Willow"
| sampo wrote:
| > Strange timing given the claim was in 2019
|
| In 2024 Google used 67 quantum bits to solve the same/similar
| random circuit sampling benchmark, that they used 53 bits in
| 2019. The discussion from 2019 on what is the relevance (if
| any) of solving random circuit simulation problems, is equally
| valid today.
|
| Maybe in 2030 Google or someone will use 200 or 400 bits to
| solve an even bigger instance of the random circuit simulation
| benchmark problem, and then we get to have this same discussion
| once again.
| bigbacaloa wrote:
| When plate tectonics was first proposed the low quality of the
| original models of the underlying mechanism led many very good
| geophysicists and geologists to reject it or to express well
| founded skepticism of the model. They knew the details and
| subtleties and the original models didn't deal well with them the
| proposal was nonetheless correct grosso modo and with time more
| adequate models of the underlying mechanisms were proposed and a
| more nuanced view of the model came into place. Now it is
| considered well established.
|
| One should consider the possibility that Gil Kalai is a similar
| sort of skeptic making well founded objections to weak arguments,
| but that nonetheless in the long run the extraordinary claims
| will turn out to be more or less correct. It's true that those
| involved in plate tectonics didn't have Bitcoin to sell you, but
| they were looking for oil.
| KK7NIL wrote:
| No theory can stand on steady ground without the critics
| checking its foundations.
|
| It's a shame we cast their role in the history of science in
| such a negative light, as if science was a game to be won or
| lost instead of a collective process where a clear path forward
| only appears in hindsight (only to be proven wrong again
| sometime later) .
|
| Oh yeah, and that anecdote you told about tectonic plates
| screams survivorship bias; that's the problem with anecdotes.
| IshKebab wrote:
| I think his point was essentially that it's possible to have
| technically correct nitpicks that are irrelevant. You see
| this all the time from naysayers.
| Veen wrote:
| You also see institutions and researchers exaggerating and
| confabulating all the time, so the sceptics are a useful
| corrective, especially if they happen to be right.
| KK7NIL wrote:
| I understood that. My point is that they aren't irrelevant,
| they help drive the new theory forward.
|
| Galileo's initial results could not predict many things
| that the old geo-centric models could predict for
| centuries.
|
| This is almost inevitable with a groundbreaking new
| framework, but the skeptics aren't wrong to point it out,
| it's up to the supporters to show it can do what old model
| can do and more, which Galileo was never quite able to show
| in his lifetime, if I recall correctly.
|
| Again, it's easy to look back and talk about how these
| "irrelevant nitpicks" of tectonic plates and helio-centrism
| were "wrong" or "irrelevant", but that's just not how
| science works, you don't get to skip over the details when
| you present a theory that undermines everything we know,
| that's just crackpot behavior.
| rcxdude wrote:
| Indeed. Galileo was up against a model that was much more
| useful and matched better with the available evidence and
| understanding: Often it's described as Copernicus vs
| Ptolemy, but while Galileo's observations conclusively
| destroyed Ptolemy by showing the other planets rotated
| around the sun, Brahe had a model where that was true,
| but the sun revolved around the earth, and it was
| functionally identical to the Copernican model except
| that it didn't require the earth to rotate and it was
| easier to calculate because it used fewer epicycles. It
| was Kepler that actually fixed the problem (before
| telescopes, even!) with epicycle-based models by making
| the paths ellipses, and it took the modern understanding
| of velocity, acceleration, and momentum which Newton
| perfected (neatly deriving Kepler's ellipses as well),
| along with experiments by a few other scientists
| demonstrating the coriolis effect on dropped objects to
| actually produce direct evidence of the earth's rotation
| and address the objections of Galileo's detractors (And
| Foucault hammered it home with his pendulum). Some of
| Galileo's contemporaries attempted similar experiments
| but failed because the effect was too small.
| ilya_m wrote:
| > Oh yeah, and that anecdote you told about tectonic plates
| screams survivorship bias; that's the problem with anecdotes.
|
| Very good point. For every tectonic plates theory or
| heliocentric system or H. pylori causing ulcers there are
| thousands of claims that are plain wrong. Statistically
| speaking, knowledgeable critics acting in good faith (eg, not
| having strong conflict of interests) are correct with the
| overwhelming probability.
| Lerc wrote:
| I'd add to this and say the probability being against a
| theory creates a risk of less than thorough dismissals of
| claims.
|
| You get this all the time with perpetual motion machines.
| The near certainty of the claim being false leads to
| confident dismissals that go 'blah, blah, laws of physics,
| blah blah thermodynamics, therefore can't happen'
|
| The real question to be asking about a claim of a perpetual
| motion machine is 'Where does the new energy come into
| being?'.
|
| Citing laws of physics won't help you because any claim to
| have made a perpetual motion machine is implicitly claiming
| to be a proof by counterexample that one of those laws is
| wrong.
| nkrisc wrote:
| > Citing laws of physics won't help you because any claim
| to have made a perpetual motion machine is implicitly
| claiming to be a proof by counterexample that one of
| those laws is wrong.
|
| Citing the laws of physics in this case is the shorthand
| way to point the overwhelming number of proofs by example
| that the laws are correct.
| Lerc wrote:
| It doesn't matter how many examples you have for a law. A
| single genuine counterexample counts as a disproof.
|
| If your law is all liquids flow off a ducks back. Water
| off a ducks back does not prove it. Acid off a ducks back
| disproves it. https://i.imgflip.com/7waajp.png
|
| I don't think it is a matter of a shorthand. I think it
| is because humans have a tendency to express a strong
| opinion when they intend to express that a weaker opinion
| is strongly held. Citing laws of physics does not say
| "Your perpetual motion machine won't work" but rather "I
| am confident that your perpetual motion machine will be
| shown to not work".
| nkrisc wrote:
| Yes, that's fair and I was sloppy with my phrasing. What
| I meant was that if you have 1,000 practical applications
| that function on the assumption the law is true and they
| behave as predicted, and then you have a single example
| that appears to disprove, then extraordinary claims
| require extraordinary evidence.
|
| A single device, made in some garage, that appears to
| disprove it is simply not rigorous enough to prove
| anything and isn't worth third party investigation until
| the creator has shown they've ruled out possible
| explanations.
| nuancebydefault wrote:
| Still, most laws of physics found by humans are wrong,
| every so many years they get refined by laws that are a
| bit less wrong.
| hooverd wrote:
| Nobody wants to seriously engage with the perpetual
| motion cranks who CC the entire department on a novel
| length email.
| GTP wrote:
| I still see a difference here: the blog post author isn't
| claiming that we will never have quantum computers. What he is
| disputing, is Google's claim that a specific quantum device
| that they have is already able to perform several orders of
| magnitude better than classical computers. Arguing that this is
| false, is different from arguing about what will happen in the
| future.
| gizmondo wrote:
| > I still see a difference here: the blog post author isn't
| claiming that we will never have quantum computers.
|
| He's very much claiming this, e.g. https://www.math.ucdavis.e
| du/~deloera/TEACHING/VIDEOS/Kalai-...
| GilKalai wrote:
| Hi everybody, my post summarizes an on-going 5-year research
| project and four papers about the 2019 Google experiment. The
| timing of the post was indeed related to Google's Willow
| announcement and the fantastic septillion assertion. It is not
| clear why Google added to the announcement of nice published
| results about quantum error correction a hyped undocumented
| fantastic claim. I think that our work on Google's 2019
| experiment provides useful information for evaluating Google's
| scientific conduct.
| vitus wrote:
| Hi! I am under the impression that you're one of the better-
| known skeptics of the practicality of QEC. And to my untrained
| eye, the recent QEC claim is the more interesting one of the
| two.
|
| (I am inclined to ignore the claims about quantum supremacy,
| especially when they're based on random circuit sampling which
| as you pointed out made assertions that were orders of
| magnitude off because nobody cares about this problem
| classically, and so there is not much research effort into
| finding better classical algorithms. And of course, there's a
| problem with efficient verification, as Aaronson mentions in
| his recent post.)
|
| I've seen a few comments of yours where you mentioned that this
| is indeed a nice result (predicated on the assumption that it's
| true) [0, 1]. I worry a bit that you're moving the goalposts
| with this blog post, even as I can't fault any of your
| skepticism.
|
| I work at Google, but not anywhere close to quantum computing,
| and I don't know any of the authors or anyone who works on
| this. But I'm in a space where I feel impacts of the push for
| post-quantum crypto (e.g. bloat in TLS handshakes) and have
| historically pooh-poohed the "store now, decrypt later" threat
| model that Google has adopted -- I have assumed that any
| realistic attacks are at a minimum decades away (if they ever
| come to fruition), and very little (if any) of the user data we
| process today will be relevant to a nation-state actor in, say,
| 30 years.
|
| If I take the Willow announcement at face value (in particular,
| the QEC claims), should I update my priors? In particular, how
| much further progress would need to be made for you to abandon
| your previously-stated skepticism about the general ability of
| QEC to continue to scale exponentially? I see a mention of one-
| in-a-thousand error rates on distance-7 codes which seems
| tantalizingly close to what's claimed by Willow, but I would
| like to hear your take.
|
| [0] https://gilkalai.wordpress.com/2024/08/21/five-
| perspectives-...
|
| [1]
| https://quantumcomputing.stackexchange.com/questions/30197/#...
| giancarlostoro wrote:
| > very little (if any) of the user data we process today will
| be relevant to a nation-state actor in, say, 30 years.
|
| The NSA is most likely interested in all data let's be
| honest. At a bare minimum, in all foreign actor data.
| pera wrote:
| > _If I take the Willow announcement at face value (in
| particular, the QEC claims)_ [...]
|
| Considering that Google's 2019 claim of quantum supremacy
| was, at the very least, severely overestimated
| (https://doi.org/10.48550/arXiv.1910.09534) I would wait a
| little bit before making any decisions based on the Willow
| announcement.
| marcinzm wrote:
| > very little (if any) of the user data we process today will
| be relevant to a nation-state actor in, say, 30 years.
|
| 30 year old skeletons in people's closets can be great
| blackmail to gain leverage with.
|
| edit: As I understand it this is a popular way for state
| actors to "flip" people. Threaten them with blackmail unless
| they provide confidential information or do some actions.
| dboreham wrote:
| I'm confused by this line of thinking. Are there really
| actors who a) do have the entire internet traffic since
| forever stored, but b) lack the resources to just go get
| whatever targets' sensitive data they want, right now?
| 542354234235 wrote:
| The data this actor wants may be in an air gapped secure
| facility, for example Iran's nuclear facilities.
| Decrypting old social media messages that show that a
| scientist at that facility had a homosexual relationship
| while he was in college in Europe would give you access
| in a way you didn't have before.
|
| That is an extreme example but high value information is
| often stored and secured in ways that are very resistant
| to theft. Using less secure and/or historical data to
| gain leverage over those with access to that data is
| exactly how spies have been doing things for centuries.
| WhitneyLand wrote:
| Would be interested to hear your response to Scott Aaronson's
| comment:
|
| "Gil's problem is that the 2019 experiment was long ago
| superseded anyway: besides the new and more inarguable Google
| result, IBM, Quantinuum, QuEra, and USTC have now all also
| reported Random Circuit Sampling experiments with good
| results."
| supernewton wrote:
| You know he's been responding directly on Scott Aaronson's
| blog, right?
| fluoridation wrote:
| You know people sometimes don't know things, right?
| VirusNewbie wrote:
| he stopped responding when Scott told him how his
| prediction was wrong.
| GilKalai wrote:
| I think that I responded over Scott's blog but I can respond
| again perhaps from a different angle. I think it that is
| important to scrutinize one (major) experiment at a time.
|
| We studied the Google 2019 claims and on the way we also
| developed tools that can be applied for further work and we
| identified methodological problems that could be relevant in
| other cases (or better could be avoided in newer
| experiments). Of course, other researchers can study other
| papers.
|
| I don't see in what sense the new results by Google,
| Quantinuum, QuEra, and USTC are more inarguable and I don't
| know what experiment by IBM Scott refers to. And also I don't
| see why it matters regarding our study.
|
| Actually in our fourth paper there is a section about quantum
| circuits experiments that deserves to be scrutinized (that
| can now be supplemented with a few more), and I think we
| relate to all examples given by Scott (except IBM) and more.
| (Correction: we mention IBM's 127 qubit experiment, I
| forgot.)
| nickpsecurity wrote:
| I appreciate you doing peer review of their claims. I have a
| few questions about the supremacy claim.
|
| Are there good write-ups on the random, sampling problem that
| would help implement its get started?
|
| What are the top classical algorithms, esp working
| implementations, for this problem?
|
| Have the classical implementations been similarly peer reviewed
| to assess their performance?
| amirhirsch wrote:
| Welcome to Hacker News Gil! I'm a big fan of your work in
| complexity theory and have thought long and hard on the
| entropy-influence conjecture revisiting it again recently after
| Hao Huang's marvelous proof of the sensitivity conjecture.
|
| To answer your question on why the hyped fantastic claim, as
| you must know, the people who provide the funds for quantum
| computing research almost certainly do not understand the
| research they are funding, and need as feedback a steady stream
| of fantastic "breakthroughs" to justify writing the checks.
|
| This has made QC research ripe for applied physicists who are
| skilled in the art of bullshitting about Hilbert Spaces. While
| I don't doubt the integrity of a plurality of the scientists
| involved, I can say with certainty that approximately all of
| the people working on Quantum Computing Research would not take
| me up on my bet of $2048 that RSA2048 will not be factored by
| 2048 --- and would happily accept $204,800,000 to make arrays
| of quantum-related artifacts. Investors require breakthroughs
| or the physicists will lose their budget for liquid gases --
| certainly exceeding $2048.
|
| While there might be interesting science discovered along the
| way, I think of QC a little like alchemy: the promise of
| unlimited gold attracted both bullshitters and serious
| physicists (Newton included) for centuries, but the physical
| laws eventually emerged that it is not scalable to turn lead
| into gold. Similarly it would be useful to determine the
| scaling laws for Quantum Computers. How big of an RSA key is
| needed before even a QC exceeds the total number of particles
| in the universe to factor it in reasonable time? Is 2048 good
| enough that we can shelf all the peripheral number-theory
| research in post-quantum-cryptography? Let's not forget the
| mathematicians too!
| sgt101 wrote:
| I think Shor's scales lineally, if it's possible to do the
| fine grain control of the most significant bits. Some people
| don't think that's a problem, but if it is then growing keys
| will be an effective defense.
| amirhirsch wrote:
| The argument is that error correction doesn't scale.
| adgjlsfhk1 wrote:
| that's a tough argument given that there are already
| known algorithms to scale it. it's possibly QM is just
| broken, but it it's not, it's hard to see how error
| correction wouldn't work
| amirhirsch wrote:
| But we're literally having this discussion with Gil Kalai
| in the next room.
| sgt101 wrote:
| There's a specific view (as I understand it) that QFT's
| don't scale https://arxiv.org/abs/2306.10072 but some
| folks seem to dismiss this for reasons I just don't grok
| at all.
| tmvphil wrote:
| You are too certain. Polls of working quantum researchers put
| significant credence on breaking RSA within 20 years.
| https://globalriskinstitute.org/publication/2023-quantum-
| thr...
| light_hue_1 wrote:
| You should not put any weight on surveys like this.
|
| I'm an ML/AI researcher. I get similar surveys regularly. I
| don't reply, neither do my colleagues. The people who reply
| are a self selected group who are heavily biased toward
| thinking that AGI will happen soon. Or they have a
| financial interest in creating hype.
|
| Most of the experts from that report have a direct
| financial benefit from claiming that this will happen
| really soon now.
| sgt101 wrote:
| Thank you for your work and perspective - it's important that
| science is carefully reviewed and that doing the review is well
| regarded.
| noqc wrote:
| I have a silly question, and I'm going to shamelessly use HN to
| ask it.
|
| In Kitaev's construction of the high purity approximation to a
| magic state, he starts with the assumption that we start with a
| state which can be represented as the tensor product of n mixed
| states which are "close enough". I don't understand where this
| separability property comes from. My (very) naive assumption
| would be that there is some big joint state which you have a
| piece of, and the information that I have about this piece are
| n of its partial traces, which are indeed n copies of the "poor
| man's" magic state.
|
| Can I know more than that? There's lots of stuff in the
| preimage of these partial traces. Why am I allowed to assert
| that I have the nicest one?
| ziofill wrote:
| Can it be that he assumes you have some device that produces
| somewhat bad magic states and then you distill them into a
| better one? That would be the typical situation in practice.
| sampo wrote:
| > It is not clear why Google added [...] a hyped undocumented
| fantastic claim.
|
| I think it's clear.
| EvgeniyZh wrote:
| In 2019 you asserted [1] that attempts of creating distance-5
| surface code will fail. Do you think you were wrong? If so,
| what was your mistake and why do you think you made it? If not,
| what's the problem with the Google's results? Have your
| estimations of feasibility of quantum computers changed in
| light of this publication?
|
| [1] https://arxiv.org/abs/1908.02499
| r33b33 wrote:
| Let's talk about things that actually matter - where to invest in
| post-quantum world?
|
| I'll keep this short.
|
| - Google's Willow quantum chip significantly outpaces current
| supercomputers, solving tasks in minutes that would otherwise
| take billions of years.
|
| - Hypothesis: Accelerating advancements in tech and AI could lead
| to quantum supremacy arriving sooner than the 2030s, contrary to
| expert predictions.
|
| - Legacy banking systems, being centralized, could transition
| faster to post-quantum-safe encryption by freezing transfers, re-
| checking processes, and migrating to new protocols in a
| controlled manner.
|
| - Decentralized cryptocurrencies face bigger challenges:Hard
| forks are difficult to coordinate across a decentralized network.
|
| - Transitioning to quantum-safe algorithms could lead to longer
| transaction signatures and significantly higher fees, eroding
| trust in the system.
|
| - If quantum computers compromise current cryptography, tangible
| assets (e.g., real estate, stock indices) may retain more value
| compared to digital assets like crypto.
|
| Thoughts?
| vishnugupta wrote:
| > Legacy banking systems,
|
| From what I know about banking world, though second hand,
| having been working in payment processing systems I can say
| with confidence that it's not the compute that's holding them
| back.
| GTP wrote:
| > Google's Willow quantum chip significantly outpaces current
| supercomputers, solving tasks in minutes that would otherwise
| take billions of years.
|
| This is the point that was disputed in the article, and you're
| instead taking it for granted.
| nightowl_games wrote:
| Quantum computing only solves certain classes of tasks faster,
| not all tasks, not most tasks, only a tiny amount of tasks.
| zeroonetwothree wrote:
| Actually, Grover's algorithm would speed up a wide range of
| tasks. Hardly a tiny amount.
| tsimionescu wrote:
| Only marginally, and it's going to take a loooooooong time
| until you'll have a quantum computer the size of today's
| classical computers to actually see any improvement from
| Grover's algorithm.
|
| Shor's is a completely different matter entirely: the
| difference between exponential and linear time is so huge
| that even a comparatively tiny QC (only a few million
| qubits) would significantly outpace the largest classical
| supercomputers put together on this specific problem.
| fluoridation wrote:
| It doesn't take billions of years to generate a small sampling
| of random (or random-looking) numbers.
| evandrofisico wrote:
| About your first point, "outpaces current supercomputers,
| solving tasks in minutes that would otherwise take billions of
| years.", that is the point of the article. They used their
| computer to model a system that can't be verified with a
| classic computer algorithm, so no, we are not certain that it
| is solving anything.
|
| About the other points, quantum computers are massively
| different from classic ones, so much that there are very few
| algorithms for them. For example, GPUs are faster at matrix
| multiplication because it can be implemented independent
| parallel threads, but they suck at other problemas. A quantum
| computer is good for running quantum algorithms [1], of which
| there are very few at the moment, and most of them are useful
| for simulating quantum physics. It is not a "faster" classic
| computer in any way.
|
| https://en.wikipedia.org/wiki/Quantum_algorithm
| NanoYohaneTSU wrote:
| All of this stuff is so fake. Quantum computing is a vaporware
| scam and I've been saying it for at least a decade at this point.
| Waste of time and money by VCs who wants government money
| forever.
| evandrofisico wrote:
| Quantum computing seems to be in the same realm as nuclear
| fusion as a power source. My Quantum theory professor used to
| say that in the 1960's, when he was a physics student in the
| Soviet Union it was "the energy of the future, in 20 years
| everything will be powered by nuclear fusion".
|
| When i was an undergrad student 20 years ago I did hear that
| "soon, quantum computing will change the world", and yet here
| we are, every year someone builds a new machine but no one has
| yet to factorize that 21 = 7x3 in a general way.
| kgwgk wrote:
| Fusion is the energy of the future - and it always will be.
| short_sells_poo wrote:
| You could also say we are already using fusion power - via
| solar panels. We have a massive ball of plasma powered by
| fusion in the sky and we are harvesting the energy it
| creates at an ever growing scale.
|
| Whether we'll be able to replicate it profitably at small
| scale is a question.
| fluoridation wrote:
| Of course, by that definition all forms of power
| generation are fusion, more or less removed from the
| fusion reactor in question.
| zeroonetwothree wrote:
| Some part of geothermal energy comes from gravity which
| could be argued is not related to fusion (even if the
| matter undergoing gravity was created in fusion)
| fluoridation wrote:
| Geothermal energy is derived from differences in kinetic
| energy between different layers of the planet (so
| extracting it saps kinetic energy from the planet's
| rotation). The energy stored in the Earth's rotation
| comes from the kinetic energy in the Solar nebula, which
| itself comes from stellar explosions in the primordial
| universe, which themselves were caused by fusion.
| evandrofisico wrote:
| following that definition even fossil fuels would be
| based on fusion, as most of it is comprised of
| photosynthetic life forms.
| red_trumpet wrote:
| Wait, you had a quantum theory Prof in the 60s, but you also
| were an undergrad 20 years ago? That's a ~40 year period in
| between, makes me curious to what happened.
| riku_iki wrote:
| successful quantum transfer experiment.
| lobsterthief wrote:
| Re-read his comment--his professor was recalling something
| from the 1960s. OP did not hear this information in the
| 1960s.
| fluoridation wrote:
| The professor taught GP quantum theory during the '00s, and
| in the '60s that same professor was a physics student in
| the USSR, where it was said that by the '80s fusion would
| power everything.
| RivieraKid wrote:
| What's the most significant useful application of quantum
| computing, in other words, why should we be excited about QC, how
| will it improve people's lives?
| kuschkufan wrote:
| that one dude that has tried since forever to convince that one
| city to allow him to dig up that garbage dump for his lost
| bitcoin wallet password should be able to get the coins without
| digging then.
|
| oh and all other passwords/pass phrases/secrets might get
| broken too, if they're not yet based on quantum save algos.
| n4r9 wrote:
| If we extend the definition of "computing" slightly to include
| "coding and cryptography", then I find superdense coding quite
| exciting [0]. In a hypothetical quantum internet we could
| encode and transmit two classical bits in every qubit, which
| effectively doubles your bandwidth. There's also quantum key
| distribution [1]. In principle, quantum theory allows Alice and
| Bob to establish a shared private key which cannot be broken
| without breaking the laws of physics. You can chat privately
| with people secure in the knowledge that not even the NSA can
| possibly be listening.
|
| [0] https://en.wikipedia.org/wiki/Superdense_coding
|
| [1] https://en.wikipedia.org/wiki/Quantum_key_distribution
| qup wrote:
| > You can chat privately with people secure in the knowledge
| that not even the NSA can possibly be listening.
|
| Well, from one possible attack vector, anyway. They can still
| point lasers at your windows.
| fluoridation wrote:
| >In a hypothetical quantum internet we could encode and
| transmit two classical bits in every qubit, which effectively
| doubles your bandwidth.
|
| Hmm... What exactly are you transmitting in such a scenario?
| What's the physical layer protocol? I.e. what are the wires
| made of and what flows through them?
| evandrofisico wrote:
| Photons, most of the current efforts for quantum
| entanglement pairs transmission is using good old lasers
| over optical fiber
| fluoridation wrote:
| Well, fair enough I suppose. Although a superficial
| reading would suggest this sort of technology is at least
| fifty years away from being deployable at opposite ends
| of a submarine cable to double the capacity without
| doubling the cable-laying. It reads like it's in the very
| early experimental stage, where they're barely
| demonstrating the _plausibility_ , let alone the
| viability.
| n4r9 wrote:
| The question was why is quantum computing exciting, not
| when can we get it.
| fluoridation wrote:
| The "although" wasn't meant to invalidate it as an
| example, it was a link between two separate ideas.
| bgnn wrote:
| Only 2x bandwidth improvement?
| mapmeld wrote:
| Chemistry applications, which may be possible using the current
| or near-future era of quantum computers. It helps to have
| actual quantum effects to compute with. For example (I am not
| affiliated with this company and don't know if it works)
| https://www.quantinuum.com/products-solutions/inquanto
| alphager wrote:
| Optimization problems like placing trains on a network become
| computationally viable. We're currently using unoptimal
| solutions because calculating an optional solution would
| require way too much time.
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