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Quantum computers: amazing progress, but probably false supremacy claims

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Re: Quantum computers: amazing progress, but probably false supremacy claims

#51

Post by johncolanduoni »

the8472 wrote: post #34
undersuit wrote: post #11

My level of expertise on quantum computing is low. The announce of the imminent advent of the Quantum Computer seems to be recurring every few months these last few years because it's a moving target. HN recently featured an article about a supposed quantum-only algorithm being applied to normal computing. Algorithms are a vastly larger space to explore than general computing paradigms. Computer hardware is still adv…

> The announce of the imminent advent of the Quantum Computer seems to be recurring every few months these last few years because it's a moving target. That's mostly misreporting by the media and perhaps d-wave overselling their capabilities. If you actually listen to experts they're far more guarded in their statements.

Yes, there has been a lot of animosity in the quantum information community for a long time against D-Wave for this very reason, as researchers are worried about them over-promising and ushering in an analogue of the AI winter as a result.

Re: Quantum computers: amazing progress, but probably false supremacy claims

#52

Post by johncolanduoni »

rolltiide wrote: post #35

Am I understanding correctly that the whole idea is to get a bunch of qubits in one machine and then have them evaluate every possibility in a super dumb way but count on them to get the desired result faster than a transister based machine that knows what its looking for? And that we currently just can’t coordinate that many qubits at once and also cant keep them cool long enough to function?? This seems kind of rid…

This is not the case and is a constant frustration researchers have with how quantum computing is represented in the media. So much so that Scott Aaronson (who works on computational complexity theory, particularly as it relates to quantum computing) has a statement telling you that’s not the case in the heading of his blog: https://www.scottaaronson.com/blog/

Re: Quantum computers: amazing progress, but probably false supremacy claims

#53

Post by GistNoesis »

quanticitya wrote: post #12

If quantum supremacy was not possible, wouldn't that mean that something is wrong with our physics understanding? So when people say quantum supremacy is impossible, do they say that the device itself is extremely complicated to build (like an earth to moon elevator for example), or that quantum supremacy isn't allowed not even in principle?

Quantum computing is a typical example of taking a model (QM), further than it was ever intended to.

Instead of recognizing the fallacy, they blindly accept its promises : cramming an infinite computational power using very little mass.

They then uses the excuse that it's extremely complicated to build to cover for the lack of results demonstrating the model is holding its promises.

After a few decades, they will achieve at tremendous cost a "success" where quantum computer are typically faster by a factor 10^6 than a classical computer, and with better energy efficiency, and recognize then that the model had indeed its limits, and that quantum supremacy was never about delivering an exponential speed-up (who would be stupid enough to believe such fallacies, of course all models have their limits) but just a better way of computing.

Re: Quantum computers: amazing progress, but probably false supremacy claims

#54

Post by FartyMcFarter »

shroedingaway wrote: post #18
reikonomusha wrote: post #14

Earlier quoted context omitted.

They are truly programmable computers.

No that's the funniest aspect of the Google result. They barely have any control over what their gates do. Gil makes this point, but doesn't call it out: they're claiming supremacy by turning the challenge around. "You can't classically simulate our device (which largely does it's own thing because of issues)." A kid shoots an arrow at a target. The arrow hits the haybale, but not the target. Suddenly the kid yells "…

> They barely have any control over what their gates do.

I don't understand this, could you explain?

My understanding is that the gates are perfectly normal quantum gates, which they use to connect qubits in a programmable way. Due to the probabilistic nature of quantum computing, running this circuit generates samples from a random distribution.

Re: Quantum computers: amazing progress, but probably false supremacy claims

#55

Post by FartyMcFarter »

bjornsing wrote: post #20
lawrenceyan wrote: post #4

The usage of the word “supremacy” is probably the primary thing that rubs people the wrong way. When I first heard of it myself, it did feel a little strange. Doing some research into it though, it seems like the phrase and usage of quantum supremacy is pretty well defined and accepted by and large within the physics community. Supposedly the coiner of the term believed “quantum advantage” wouldn’t emphasize the poin…

If the points raised by the OP are nitpicks, then I guess it doesn’t matter to you that the sampled (D’) distribution is very close to some easily definable theoretical distribution (D)? If so I can easily illustrate this “good enough quantum supremacy” in my own home and on a very limited budget. The simple reason is that it is absolutely trivial to set up a physical experiment (quantum or not) where it’s very hard…

But is your low budget experiment programmable with a known sequence of well defined quantum gates? Can you statistically verify that your distribution is very close to D?

Re: Quantum computers: amazing progress, but probably false supremacy claims

#57

Post by bjornsing »

FartyMcFarter wrote: post #55
bjornsing wrote: post #20

Earlier quoted context omitted.

If the points raised by the OP are nitpicks, then I guess it doesn’t matter to you that the sampled (D’) distribution is very close to some easily definable theoretical distribution (D)? If so I can easily illustrate this “good enough quantum supremacy” in my own home and on a very limited budget. The simple reason is that it is absolutely trivial to set up a physical experiment (quantum or not) where it’s very hard…

But is your low budget experiment programmable with a known sequence of well defined quantum gates? Can you statistically verify that your distribution is very close to D?

I don’t really understand... My claim started with “if so”. Now you’re (if I understood you) asking if I’m willing to make the unconditional claim (without “if so”)?

(No. If I was I wouldn’t have used the qualifier “if so”.)

Re: Quantum computers: amazing progress, but probably false supremacy claims

#58

Post by chr1 »

GistNoesis wrote: post #53
quanticitya wrote: post #12

If quantum supremacy was not possible, wouldn't that mean that something is wrong with our physics understanding? So when people say quantum supremacy is impossible, do they say that the device itself is extremely complicated to build (like an earth to moon elevator for example), or that quantum supremacy isn't allowed not even in principle?

Quantum computing is a typical example of taking a model (QM), further than it was ever intended to. Instead of recognizing the fallacy, they blindly accept its promises : cramming an infinite computational power using very little mass. They then uses the excuse that it's extremely complicated to build to cover for the lack of results demonstrating the model is holding its promises. After a few decades, they will ach…

Is there a way to find how far a model stays valid other than taking it further than it was ever intended to? I personally like to think that physics can be explained by a discrete finite automaton so quantum computers are not possible, but believing this would be more stupid than believing the opposite. Whichever alternative is true, there is a good reason to try to build quantum computer, because the process itself will improve our understanding. And implying that there is some conspiracy to pretend quantum computers are real, is strange to say the least.

Re: Quantum computers: amazing progress, but probably false supremacy claims

#59

Post by computerex »

lawrenceyan wrote: post #48
thethirdone wrote: post #16

Earlier quoted context omitted.

> The author raises points in contention, but they largely just seem like nitpicks to me. It doesn't seem just like nitpicks to me. The core issue the author raises is the noise in the final output. If the quantum computer can only produce significantly noisy data (ie not in accordance with the theoretical distribution) whereas the conventional computer produces noiseless data, then that isn't a clear case of quantum…

We can look directly to the paper itself to see how it addresses the issues of error uncertainty that the author premises his blogpost around: “This fidelity should be resolvable with a few million measurements, since the uncertainty on FXEB is 1/√Ns, where Ns is the number of samples. Our model assumes that entangling larger and larger systems does not introduce additional error sources beyond the errors we measure…

> We can look directly to the paper itself to see how it addresses the issues of error uncertainty that the author premises his blogpost around

Can you demonstrate how the author "premises his blogpost around" the "issues of error uncertainty"? I don't think that was the main premise of the paper, at all.

Re: Quantum computers: amazing progress, but probably false supremacy claims

#60

Post by blazespin »

thethirdone wrote: post #16
lawrenceyan wrote: post #4

The usage of the word “supremacy” is probably the primary thing that rubs people the wrong way. When I first heard of it myself, it did feel a little strange. Doing some research into it though, it seems like the phrase and usage of quantum supremacy is pretty well defined and accepted by and large within the physics community. Supposedly the coiner of the term believed “quantum advantage” wouldn’t emphasize the poin…

> The author raises points in contention, but they largely just seem like nitpicks to me. It doesn't seem just like nitpicks to me. The core issue the author raises is the noise in the final output. If the quantum computer can only produce significantly noisy data (ie not in accordance with the theoretical distribution) whereas the conventional computer produces noiseless data, then that isn't a clear case of quantum…

Probably a very ignorant statement, but such noisy data really seems to point to the quantum mind hypothesis doesn't it?
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