[HN Gopher] Major Quantum Computing Strategy Suffers Serious Set...
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Major Quantum Computing Strategy Suffers Serious Setbacks
Author : elsewhen
Score : 80 points
Date : 2021-09-30 14:50 UTC (8 hours ago)
(HTM) web link (www.quantamagazine.org)
(TXT) w3m dump (www.quantamagazine.org)
| pedrosbmartins wrote:
| I remember reading a while ago about a group of quantum physicist
| that believe in a fundamental barrier to the construction of
| useful quantum computers. Is that still the case, or is it
| generally believed that a large-scale, useful quantum computer is
| simply a finite number of iterations away from reality?
| zardo wrote:
| I think that view was based on the (probably correct) idea that
| sufficiently reliable physical qubits could not be built. The
| more qubits in the computer, the more reliable the qubits would
| need to be.
|
| Since the discovery of quantum ECC, that's no longer a reason
| to believe a quantum computer can't be built, a reliable
| logical qubit can be built out of a number of less reliable
| physical qubits.
| ignorem3 wrote:
| The picture showing the vast array of cooling tubes and doodads
| say it all for me. This impossibly finicky technology will never
| achieve the promise of beating classical computers. Put it in the
| back of a drawer with the perpetual motion machine and call it a
| day.
| candyman wrote:
| The title should probably be "A Major Quantum Computing
| Strategy..." It's less surprising that way since there are quite
| a few different fundamental paths people are taking towards
| quantum computing. I'm no expert but did an in-depth project
| around "adiabatic" QC and I was satisfied that it could work for
| a number of optimization problems. With IonQ coming public this
| week I expect the level of attention on the sector to keep going
| up. There have been many false starts over the last decade. I
| wonder how close we are to commercial use?
| reikonomusha wrote:
| The people who are seriously saying we are close to commercial
| use are also typically quantum company CEOs or group leads with
| a personal financial stake, bending "commercial use" to be as
| broad as possible. Quantum computing is improving rapidly, and
| the field sees great progress, but no one has demonstrated
| anything that most reasonable people would consider "useful".
| ThePhysicist wrote:
| Honestly, the authors of the retracted paper that the article
| mentions were lucky the whole thing just blew over without
| consequences for them (probably because a very high-profile
| researcher was involved). I think if a less well-known research
| group would've edited experimental data like they did the
| community would not have been this forgiving. To be clear the
| authors didn't fabricate new data but they edited a graph in a
| way that can only be described as highly misleading and possibly
| fraudulent. My advisors would've killed me had they discovered me
| doing something like that. So IMHO interpreting this as a naive
| mistake or overzealousness doesn't do it justice. That said I'm
| no longer working in academia so I don't really care, just
| thought the handling of this incident was odd given previous
| cases of data manipulation in the Physics community.
|
| Anyway, topological quantum computing and Majorana fermions are
| interesting but the research in that area is at a stage where
| we've been with superconducting systems 30-40 years ago, i.e.
| people making the first fundamental experiments and trying to
| assemble the basic building blocks for a qubit. So I don't think
| anyone seriously bets on topological quantum computers to win the
| race.
| [deleted]
| inasio wrote:
| There must have been consequences from the Microsoft side of
| things. This issue essentially killed the main candidate in
| their quantum computing program.
| reikonomusha wrote:
| They've pivoted to a huge software play to make "the one
| quantum programming language to rule them all"--which is a
| pie many are grabbing for. IBM is similarly doing huge and
| protracted marketing campaigns to attract software developers
| to their platform, not unlike Java in the past 25 years.
| reikonomusha wrote:
| Inevitably, this article (and implications about quantum
| computing) is going to be vastly misinterpreted due to the title.
| It would be like saying "Major Shuttle Strategy Suffers Serious
| Setbacks" but the strategy is using slingshots to get us into
| orbit, ignoring the work of, say, NASA and SpaceX.
|
| This quantum computing strategy neither was nor is practiced by
| the vast majority of quantum institutions--commercial or
| otherwise. It was attempted by a group at Microsoft (and a small
| collection of other university groups) and was known from the
| start that it would be a search for essentially fundamentally new
| observations.
|
| Other quantum computing players, like Rigetti, Google, HRL
| Laboratories, IBM, Amazon, Honeywell, and others are doing an
| approach that is nothing like the article, and have demonstrated
| significant results.
| rdtsc wrote:
| Yeah probably a bit of an exaggeration. "Major" ... "Majorona
| particle" I can see how one can make a subconscious connection
| there :-)
|
| I guess I wouldn't call it major but rather "exiting" strategy.
| The theoretical result from Kitaev [1], from Microsoft
| research, was certainly interesting. Having a way not deal with
| error corrections would be really great.
|
| [1] https://arxiv.org/pdf/cond-mat/0010440.pdf
|
| > Thus an isolated Majorana site (usually called a Majorana
| fermion) is immune to any kind of error!
| HPsquared wrote:
| It should really be "A quantum computing strategy suffers..."
| amelius wrote:
| Or: "One idea in quantum computing bears no fruit"
| westurner wrote:
| "Quantized Majorana conductance not actually observed
| within indium antimonide nanowires"
|
| "Quantum qubit substrate found to be apparently
| insufficient" (Given the given methods and probably
| available resources)
|
| And then - in an attempt to use terminology from
| Constructor Theory
| https://en.m.wikipedia.org/wiki/Constructor_theory :
|
| > In constructor theory, a transformation or change is
| described as a _task_. A _constructor_ is a physical entity
| which is able to carry out a given task repeatedly. A task
| is only possible if a constructor capable of carrying it
| out exists, otherwise it is impossible. To work with
| constructor theory everything is expressed in terms of
| tasks. The properties of information are then expressed as
| relationships between _possible-_ and _impossible tasks_.
| _Counterfactuals_ are thus fundamental statements and the
| properties of information may be described by physical
| laws.[4] If a system has a set of attributes, the set of
| permutations of these attributes is seen as a set of tasks.
| A _computation medium_ is a system whose attributes permute
| to always produce a possible task. The set of permutations,
| and hence of tasks, is a _computation set_. If it is
| possible to copy the attributes in the computation set, the
| computation medium is also an _information medium_.
|
| > Information, or a given task, does not rely on a specific
| constructor. Any suitable constructor will serve. This
| ability of information to be carried on different physical
| systems or media is described as _interoperability_ , and
| arises as the principle that the combination of two
| _information media_ is also an information medium.[4] Media
| capable of carrying out quantum computations are called
| _superinformation media_ , and are characterised by
| specific properties. Broadly, certain copying tasks on
| their states are impossible tasks. This is claimed to give
| rise to all the known differences between quantum and
| classical information.[4]
|
| "Subsequent attempts to reproduce [Quantized Majorana
| conductance (topological qubits of arranged electrons)
| within indium antimonide nanowires] eventually as a
| (quantum) computation medium for the given tasks failed"
|
| "Quantum computation by Majorana zero-mode (MZM)
| quasiparticles _in indium antimonide nanowires_ not
| actually apparently possible "
|
| ... "But what about in DDR5?" Which leads us to a more
| generally interesting: "Rowhammer for qubits", which is
| already an actual Quantum on Silicon (QoS) thing.
| StatsAreFun wrote:
| This is interesting! My thinking is that quantum computing is
| shaping up to be similar to fusion in the sense that it will
| steadily march toward usability but a commercial fusion reactor
| will forever be several years away from production. Is this the
| case or am I just really ignorant of the QC field?
| mikewave wrote:
| I work on a real, cold-as-space production quantum computer and
| its cloud service that you can sign up and use for free today -
| the D-Wave Advantage system, with 5000+ qubits, that you can
| use via D-Wave Leap.
|
| The difference here is that we produce a quantum annealer,
| which is useful for optimization problems instead of for
| database searches + factoring. It's already delivering some
| real-world value for early applications.
|
| While gate model machines are interesting, D-Wave took the tack
| of implementing the model of QC most likely to lead to actual
| useful applications within our lifetimes. Gate-model QC does
| seem to be very useful, but until it reaches millions of
| physical qubits it's not going to be producing any results
| beyond pet laboratory projects, and it remains to be seen if
| that's even physically possible. In contrast, quantum annealing
| has been able to grow at a good rate both in terms of qubit
| count, degree of connectivity between qubits, and also in terms
| of reaching lower noise and better quality results.
|
| We also have hybrid solvers that combine the state of the art
| in classical algorithms with QPU sampling to get the lowest
| energy state possible with a much larger graph than we can do
| in hardware.
|
| I think it's a very interesting field to follow, there are huge
| investments being made and real progress is happening on a
| number of fronts. Our competitors are trying to bring live
| systems to market, too, but it's harder to see them being much
| more useful than simulators for the foreseeable future.
| ogogmad wrote:
| What do you think of Scott Aaronson's previous scepticism
| towards D-wave computers? I think it boiled down to them not
| doing a comparison with the best classical algorithms running
| on the best classical computers. Are your comparisons apples
| to apples?
|
| I think what you wrote makes sense as a way of maximising the
| chances of producing a viable product. I suppose there aren't
| any guarantees that it will be competitive with bog-standard
| computers, but it might be a reasonable gamble.
| mikewave wrote:
| I work on the classical computers around the exotic stuff,
| so I'm not really qualified to comment. Either way,
| Aaronson's negative commentary - which is many years out of
| date, at this point - is not something that anyone pays
| very much mind to, because at the end of the day one can't
| allow a mere critic on the sidelines to get in the way of
| actually producing real machines.
|
| > maximising the chances of producing a viable product
|
| That's the goal. The annealing QPU is a co-processor, like
| your GPU, like vector processors, or a DSP, etc. It doesn't
| need to compete with classical compute on the things
| classical compute is good at; it needs to compete on the
| things classical compute is bad at, or at the very least,
| bad at without throwing massive piles of money at it. There
| is a crossover point for optimization problems where we
| will be able to show a price/performance advantage over
| classical compute, which we term Quantum Advantage (vs. the
| more divisive term of Quantum Supremacy).
|
| The trick at this point is formulating problems in such a
| way as to be something you can run on our hardware, which
| still requires a deep mathematical skillset. This is
| something we're building on... perhaps pay attention to our
| Qubits conference coming up next week -
| https://www.qubits.com/ - there should be some interesting
| announcements!
| seibelj wrote:
| Considering the much-touted "quantum supremacy" achievement was
| extremely contrived, it seems like the hype has gotten far
| ahead of the reality.
| reikonomusha wrote:
| Just so nobody is misinterpreting what you're saying (that
| somehow the quantum supremacy result was a farce): Quantum
| supremacy is a very important milestone in quantum computing.
| Being contrived or academic is fine because it's intended to
| be fundamental science. The term "supremacy" was already long
| a part of the quantum computing lexicon before the result was
| achieved, and it has essentially a precise mathematical
| definition. I think it's an unfortunate term, but it
| certainly _wasn't_ invented for the occasion.
|
| Some people blew the result out of proportion, making claims
| that finally quantum computers are provably useful/the
| best/etc. Google (who got the result) know these claims are
| not true, but in their typical character, turned a blind eye
| to the hype that ensued, because who doesn't want free press?
| kvathupo wrote:
| Don't we have a provable guarantee in the case of the
| traversal of glued trees via oracle, i.e. no classical
| algorithm has lower query-complexity? (Granted, the same
| can't be said for Grover's)
|
| See section 16.4 of these notes (pdf warning) [1].
|
| [1] - http://www.cs.umd.edu/~amchilds/qa/qa.pdf
| simiones wrote:
| These are two somewhat separate problems:
|
| 1. Do theoretical quantum computers have different
| properties than theoretical classical computers? (or, QBP
| = P? )
|
| 2. Does some particular physical device show the
| properties associated with a theoretical quantum
| computer?
|
| Of course, if 1 is false, than 2 is more or less
| irrelevant. However, even if 1 true, that still leaves
| the question of 2 for any particular device.
|
| The Google and Chinese experiments have proven 2 for
| their own particular devices.
|
| This is an important milestone not just for these
| particular devices, but also because, prior to this,
| there was also a question 3: do QM systems actually
| exhibit the properties of a theoretical quantum computer?
| After the Google result, this has been almost entirely
| put to rest: the answer is yes.
| reikonomusha wrote:
| Excellent explanation and separation of concerns.
| simiones wrote:
| The quantum supremacy milestone was still extremely
| important, even if it doesn't in any way mean that we are
| close to a working QC.
|
| Before this milestone, there were still reasons to believe
| that quantum computers could not, in principle, beat
| classical computers, that there is some fundamental
| limitation of the universe that would actually prevent
| quantum effects from making a QC work.
|
| After this milestone, the only "hope" for such a fundamental
| limitation lies in the area of quantum error correction - the
| possibility that, somehow, you would lose the theoretical
| speed-up from QC by having to re-run the algorithm enough
| times to get an accurate enough response. As Scott Aaronson
| explains, while disappointing in terms of QC, this would also
| be extremely exciting for quantum mechanics itself and for
| our understanding of the universe.
|
| So, the Google and Chinese quantum supremacy demonstrations,
| while useless as actual computations, serve a very important
| role in showing that actual quantum computers have properties
| that can't be replicated by classical computers, which was
| not proven before these experiments were run.
|
| Equivalently, you can say that these experiments have proven
| that the physical systems being called "quantum computers"
| have at least some properties of the theoretical mathematical
| concept of a quantum computer - something that no previous
| systems had proven conclusively. In this way, this can also
| be seen as a new test of Quantum Mechanics' predictions,
| since it proves once again that real physical systems do
| exhibit some of the complex behaviors predicted by the maths.
| sampo wrote:
| > Before this milestone, there were still reasons to
| believe that quantum computers could not, in principle,
| beat classical computers
|
| The laws of Quantum Mechanics clearly allow quantum
| computers. So those beliefs must have included something
| that goes beyond known physics i.e. the assumption of some
| supernatural effect?
| reikonomusha wrote:
| The laws of Newtonian physics also "allow" frictionless,
| spherical cows.
|
| The laws of relativity and nuclear physics "allow" a
| tablespoon of salt to provide 453 GWh of energy.
| fooker wrote:
| The quantum supremacy demonstrations were effectively
| showing that a quantum computer can simulate a quantum
| computer better than a classical computer. That is sort of
| meh...
| reikonomusha wrote:
| That is not an accurate reduction. They showed they can
| sample from a particular probability distribution which
| is hard to do classically.
|
| And fundamental developments in physics or theoretical
| computer science aren't concerned with what's "meh". It
| was a logical next step to determining whether these
| machines do something they're theoretically supposed to
| be able to do.
| xxpor wrote:
| I think for a lot of people the real question is how far
| ahead the intel agencies (really, the NSA) are. How many
| years will there be a super mega top secret quantum computer
| sitting in the basement of Ft. Meade breaking DH before
| someone figures it out?
| daxfohl wrote:
| Not yet. The way this kind of stuff usually works is that,
| as we get closer we'll see some high-profile researchers
| suddenly quit their jobs to go work on "something else".
| xxpor wrote:
| Yeah that'd make sense. Thinking about it, that's exactly
| what happened with the Manhattan Project.
| kvathupo wrote:
| Considering government pay and bureaucracy, this is
| probably unlikely today
| ryan93 wrote:
| No. the smartest people work for universities or private
| companies. people would know if top scientists were leaving
| for the NSA
| xxpor wrote:
| That's true generally, but I thought I saw some stat that
| NSA hired some crazy % of the math PhDs in the US (like
| 30%+). I also thought the national labs were considered
| pretty good places to work.
| thehappypm wrote:
| "Why shouldn't I work for the N.S.A.? That's a tough one,
| but I'll take a shot. Say I'm working at N.S.A. Somebody
| puts a code on my desk, something nobody else can break.
| Maybe I take a shot at it and maybe I break it. And I'm
| real happy with myself, cause I did my job well. But
| maybe that code was the location of some rebel army in
| North Africa or the Middle East. Once they have that
| location, they bomb the village where the rebels were
| hiding and fifteen hundred people I never met, never had
| no problem with, get killed. Now the politicians are
| sayin', "Oh, send in the Marines to secure the area"
| cause they don't give a shit. It won't be their kid over
| there, gettin' shot. Just like it wasn't them when their
| number got called, cause they were pullin' a tour in the
| National Guard. It'll be some kid from Southie takin'
| shrapnel in the ass.
|
| And he comes back to find that the plant he used to work
| at got exported to the country he just got back from. And
| the guy who put the shrapnel in his ass got his old job,
| cause he'll work for fifteen cents a day and no bathroom
| breaks. Meanwhile, he realizes the only reason he was
| over there in the first place was so we could install a
| government that would sell us oil at a good price. And,
| of course, the oil companies used the skirmish over there
| to scare up domestic oil prices. A cute little ancillary
| benefit for them, but it ain't helping my buddy at two-
| fifty a gallon.
|
| And they're takin' their sweet time bringin' the oil
| back, of course, and maybe even took the liberty of
| hiring an alcoholic skipper who likes to drink martinis
| and fuckin' play slalom with the icebergs, and it ain't
| too long 'til he hits one, spills the oil and kills all
| the sea life in the North Atlantic. So now my buddy's out
| of work and he can't afford to drive, so he's got to walk
| to the fuckin' job interviews, which sucks cause the
| shrapnel in his ass is givin' him chronic hemorrhoids.
| And meanwhile he's starvin', cause every time he tries to
| get a bite to eat, the only blue plate special they're
| servin' is North Atlantic scrod with Quaker State.
|
| So what did I think? I'm holdin' out for somethin'
| better. I figure fuck it, while I'm at it why not just
| shoot my buddy, take his job, give it to his sworn enemy,
| hike up gas prices, bomb a village, club a baby seal, hit
| the hash pipe and join the National Guard? I could be
| elected president."
|
| Good Will Hunting
| daxfohl wrote:
| No, there are a few well understood approaches to physically
| creating a QC, each of which are seeing incremental progress
| every year. That's not to say there's a clear path from here to
| there, but it's a lot closer to clear than fusion. Fusion is
| still (to my understanding) closer to a research topic without
| a clear cut approach.
|
| That's also not to say that these roles will not reverse in the
| future. Perhaps some fundamental problem is found with the
| existing QC approaches, and someone discovers a fusion approach
| that is straightforward and just requires a big engineering
| effort. But right now to me it seems like fusion is closer to a
| Majorana-based QC (though Majorana is slightly more nebulous
| since even the theory isn't completely there) than it is to QC
| in general.
| inasio wrote:
| Relatively recently there has been a ton of funding pouring
| into PsiQuantum ($650M, a bunch of it from Microsoft, perhaps
| reallocating their Majorana investment), which is building a
| photonic QC. There may be something there, or it could be
| another Magic Leap...
| bawolff wrote:
| I think the difference is that nobody except snake oil salesmen
| and people who want investors in their qc company were saying
| that useful quantum computers were only a couple years away.
| titties4fr33 wrote:
| This is really interesting but off-topic.
|
| I come to hackernews for gay sex and covid conversation.
|
| I'm really looking forward to the AMA from Fauci.
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