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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

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?

seibelj 5y ago
Considering the much-touted "quantum supremacy" achievement was extremely contrived, it seems like the hype has gotten far ahead of the reality.
- xxpor 5y ago
  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?
  - kvathupo 5y ago
    Considering government pay and bureaucracy, this is probably unlikely today
  - ryan93 5y ago
    No. the smartest people work for universities or private companies. people would know if top scientists were leaving for the NSA
    - xxpor 5y ago
      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 5y ago
      "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 5y ago
    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 5y ago
      Yeah that'd make sense. Thinking about it, that's exactly what happened with the Manhattan Project.
- reikonomusha 5y ago
  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 5y ago
    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 http://www.cs.umd.edu/~amchilds/qa/qa.pdf
    - simiones 5y ago
      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 5y ago
        Excellent explanation and separation of concerns.
- simiones 5y ago
  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 5y ago
    > 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 5y ago
      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.
    - jlokier 5y ago
bawolff 5y ago
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.
daxfohl 5y ago
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 5y ago
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...
mikewave 5y ago
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 5y ago
  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 5y ago
    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/ https://www.qubits.com/ - there should be some interesting announcements!

seibelj 5y ago

Considering the much-touted "quantum supremacy" achievement was extremely contrived, it seems like the hype has gotten far ahead of the reality.

xxpor 5y ago
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?
- kvathupo 5y ago
  Considering government pay and bureaucracy, this is probably unlikely today
- ryan93 5y ago
  No. the smartest people work for universities or private companies. people would know if top scientists were leaving for the NSA
  - xxpor 5y ago
    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 5y ago
    "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 5y ago
  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 5y ago
    Yeah that'd make sense. Thinking about it, that's exactly what happened with the Manhattan Project.
reikonomusha 5y ago
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 5y ago
  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 http://www.cs.umd.edu/~amchilds/qa/qa.pdf
  - simiones 5y ago
    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 5y ago
      Excellent explanation and separation of concerns.
simiones 5y ago
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 5y ago
  > 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 5y ago
    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.
  - jlokier 5y ago

bawolff 5y ago

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.

daxfohl 5y ago

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 5y ago

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...

mikewave 5y ago

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 5y ago
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 5y ago
  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/ https://www.qubits.com/ - there should be some interesting announcements!