[DebtDeflation]

>to notice they left out the gates to the wrong answer

Can you explain this a little more? I've seen similar references to this elsewhere. If it means what I think it means, it's kind of a really big deal. But it may mean something else.

[scottlocklin]

http://www.theory.caltech.edu/~preskill/pubs/preskill-1996-n...

[gjm11]

That doesn't explain in what sense this entirely different paper from 20 years later allegedly "left out the gates to the wrong answer".

The paper I linked to says, e.g., the following:

> Subsequent multipliers can similarly be replaced with maps by considering only possible outputs of the previous multiplications. However, using such maps will become intractable, [...] Thus, controlled full modular multipliers should be implemented.

So in at least one case they are explicitly not taking a particular shortcut because it doesn't scale to factorizing larger numbers. If you say they are taking other shortcuts that don't scale by "leaving out the gates to the wrong answer", then I think you owe us an actual explanation of what shortcuts they are taking and how you know you're taking them, rather than just a link to a paper from 1996 that says how to take some shortcuts.

[scottlocklin]

Frankly I don't owe you or the muppets attempting to participate in this thread by zombie-walking "MUH PRESS RELEASES" a damn thing: if you want to believe in pixie dust, you're free to do so. None of the "quantum computing results" factoring the number 15 have done the actual Shor algorithm -they've all used the shortcut described in this paper. Someone below posted another paper pointing out the same thing, as well as some discussion on a forum .... pointing out the same thing.

It's not my fault you believe in press releases without understanding what they mean.

[gjm11]

I haven't said a thing about press releases.

The paper I linked to (1) doesn't cite Preskill et al and (2) explicitly claims not to be taking shortcuts that don't generalize to numbers other than 15; as well as the bit I quoted earlier, they say "for a demonstration of Shor’s algorithm in a scalable manner, special care must be taken to not oversimplify the implementation—for instance, by employing knowledge about the solution before the actual experimental application" and cite an article in Nature decrying cheaty oversimplifications of Shor's algorithm.

I don't see anything in their description of what they do that seems to me to match your talk of "deleting the gates that lead to the wrong answer".

(The Kitaev paper they cite also doesn't cite Preskill et al, unsurprisingly since it predates that, and also doesn't contain anything that looks to me like cheaty shortcut-taking.)

It is, of course, possible that that paper does take cheaty shortcuts and I've missed them. It is, of course, possible that its authors are flatly lying about what they're doing, and trying to hide the evidence by not citing important prior papers that told them how to do it. If so, perhaps you could show us where.

Otherwise, I for one will be concluding from the surfeit of bluster and absence of actual information in your comments so far that you're just assuming that every alleged "factoring of 15" is indulging in the dishonesty you think they are, and that you aren't interested in actually checking.

(You don't, indeed, owe anyone anything. It's just that if you want to be taken seriously, that's more likely if you offer something other than sneering and bluster.)

[scottlocklin]

Again, as I said before: even assuming they didn't take shortcuts (the paper you mention is essentially "we took shortcut X instead of Y" -and of course, no quantum error correction is evident): congratulations, your miracle technology is now capable of factoring the number 15. All they have to do now is add all the things that make quantum computing useful and eventually they will honestly be able to factor the number 21. Should happen ... I dunno, care to make a prediction when?

Pointing this out is apparently necessary; I don't know why it triggers people so to point out that virtually the entire field up to the present day has consisted of grandstanding quasi-frauds. And that you apparently have to understand things and read extremely carefully to notice, because whatever honest workers there may be don't see it as in their interest to point such things out as it may upset their rice bowls.

You have someone else in another thread insisting that annealing can factor giant prime numbers which is equally bullshit. Do you expect me to patiently, precisely and (somehow) dispassionately point out every line of bullshit in every quantum computing paper published? The mere fact that the field is pervasive with bullshit, publishes papers and announcements that are known to be bullshit, and promises all kinds of pixie dust bullshit on a regular basis ought to give you some slight skepticism, some Bayesian prior that the grand pronunciamentos of this clown car should be treated with a bit of skepticism.

[gjm11]

I agree that "can factor 15" isn't terribly impressive. (Well, it's kinda impressive, because making a quantum computer do anything at all is really hard.) I very much agree that D-Wave's quantum annealing stuff is bullshit, especially if anyone is claiming it's any good for factoring large numbers. I don't expect you, or anyone, to point out every bit of bullshit in every paper published.

I'm all in favour of pointing out bullshit. But there's a boy-who-cried-wolf problem if you just indiscriminately claim that everything is the same kind of bullshit without checking it.

Of course that doesn't mean that you're obliged to check everything. You can say "I expect this is bullshit of the usual sort but haven't checked". But if you say "this is bullshit of the usual sort" without checking and it turns out that that isn't the case (it looks to me as if the paper I linked to isn't the kind of bullshit you describe) then you take a credibility hit that makes all your bullshit-spotting much less useful than if you were more careful.