Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The Case Against Quantum Computing

spectrum.ieee.org

Post reply on HN
Print view View original

81–89 of 89 posts

Re: The Case Against Quantum Computing

#81

Post by xpuente »

mathgenius wrote: post #32

This is a lame article, bordering on click-bait. It is totally reasonable to predict a quantum computing winter, but all the supporting arguments here seem to be about how "hard-headed engineers" know best. > So the number of continuous parameters describing the state of such a useful quantum computer at any given moment must be at least 2^1000, which is to say about 10^300. That’s a very big number indeed. Yes this…

>I do imagine it, every day. But I'm a professional, so maybe that doesn't count?

Can englight us?

Re: The Case Against Quantum Computing

#82

Post by xpuente »

tezthenerd wrote: post #51
tezthenerd wrote: post #35

Here is a way to see the fallacy of the OMG, its 10^300 variables, thats crazy style of “argument”. Consider a probabilistic classical algorithm on 500 bits. Perhaps a Monte Carlo simulation of an Ising model for example. Note first that the most general probability distribution over the 500 classical bits takes 2^500 real numbers to specify. (You have to specify P(000…0) and P(000…1) and… P(111…1)). [You should comp…

Let me present it a different way. Someone comes to you with two formal models of computing. Both models involve representing the state of the computer as a vector of real numbers, they both involve finite dimensional subsystems combined with a tensor product, both involve gates defined over the reals also combined via the tensor product and so on. That is, both models are just about evolution of a vector in some (ve…

> ... as a vector of real numbers...

Using IEEE754?

Re: The Case Against Quantum Computing

#83

Post by pavelrub »

sp332 wrote: post #65
pavelrub wrote: post #50

Earlier quoted context omitted.

It’s not particularly important how you define the term “quantum computer”, nor have I presented any definition of a "quantum computer" that you can disagree with. The point is that, as I wrote before, regardless of your definition - currently there is no discernible advantage of quantum computers over classical computers in the only metric that matters: computational power. This is what people refer to when they tal…

Grover's algorithm runs faster than any classical algorithm can https://en.wikipedia.org/wiki/Grover%27s_algorithm and it was first run on quantum hardware in 1998 according to the timeline I posted above. Literally the only difference between the state of the art and quantum supremacy is scale.

Now you are simply posting incorrect or misleading information. There is no existing implementation of Grover's algorithm on quantum hardware that demonstrated any speedup over classical computers. In fact the largest implementation of Grover's algorithm to date, on ibmqx5, has an unusable error rate.

> Literally the only difference between the state of the art and quantum supremacy is scale.

This is simply incorrect. At the moment it's unclear that quantum supremacy can be achieved at any scale whatsoever, and it's certainly possible that it's unachievable even in principle.

Re: The Case Against Quantum Computing

#84

Post by kisstheblade »

mathgenius wrote: post #32

This is a lame article, bordering on click-bait. It is totally reasonable to predict a quantum computing winter, but all the supporting arguments here seem to be about how "hard-headed engineers" know best. > So the number of continuous parameters describing the state of such a useful quantum computer at any given moment must be at least 2^1000, which is to say about 10^300. That’s a very big number indeed. Yes this…

I think your reply is knee-jerk and "lame". Why don't you enlighten us, instead of taking it so personally when somebody criticizes your field.

I thought the article was excellent and made good arguments.

Re: The Case Against Quantum Computing

#85

Post by kisstheblade »

lewisinc wrote: post #77

Shame on this article. We should be researching everything within moral limits. Everything. Research all of it so hard that there's no long any debate about whether this point or that has any standing because it's so well understood that we can just fucking move on. Regardless of the topic, if we aren't sure if it's of value - we learn as much as we can until we can allow ourselves as a species to move on. That's the…

He said that the experimental research was useful, so shame on you. What kind of a silly strawman are you trying to build.

I can see from the responses here that the field is obviously quite volatile and full of big egos with practicioners taking criticisms so personally :)

Re: The Case Against Quantum Computing

#86

Post by eigenspace »

kisstheblade wrote: post #84
mathgenius wrote: post #32

This is a lame article, bordering on click-bait. It is totally reasonable to predict a quantum computing winter, but all the supporting arguments here seem to be about how "hard-headed engineers" know best. > So the number of continuous parameters describing the state of such a useful quantum computer at any given moment must be at least 2^1000, which is to say about 10^300. That’s a very big number indeed. Yes this…

I think your reply is knee-jerk and "lame". Why don't you enlighten us, instead of taking it so personally when somebody criticizes your field. I thought the article was excellent and made good arguments.

How much working knowledge of quantum computing do you have? I can see why someone not connected to the field might think the article makes good arguments but if you are connected at all to the literature, one can see the article is bullshit.

Many of the criticisms they’re levying here are either made up or misunderstood.

Re: The Case Against Quantum Computing

#87

Post by krastanov »

feanaro wrote: post #78
krastanov wrote: post #47

Earlier quoted context omitted.

Amusing historical note: The same arguments were made about classical computers and a similar theorem (by Von Neuman) exists there.

Do you have a more precise citation of this theorem? I'm curious.

Here is PDF of a lecture he gave on the topic http://www.sns.ias.edu/pitp2/2012files/Probabilistic_Logics....

Re: The Case Against Quantum Computing

#88

Post by mathgenius »

mathgenius wrote: post #32

This is a lame article, bordering on click-bait. It is totally reasonable to predict a quantum computing winter, but all the supporting arguments here seem to be about how "hard-headed engineers" know best. > So the number of continuous parameters describing the state of such a useful quantum computer at any given moment must be at least 2^1000, which is to say about 10^300. That’s a very big number indeed. Yes this…

It looks like Dyakonov has been at this for a while:

https://www.scottaaronson.com/blog/?p=1211

Re: The Case Against Quantum Computing

#89

Post by tarboreus »

WillPostForFood wrote: post #33
tarboreus wrote: post #11

Earlier quoted context omitted.

Sulfa. White swans do come along, they're just incredibly rare.

Are they rare, or do they just happen over longer timeframes than we want? Just about any mainstream technology today would appear to be too good to be true to someone ~100 years ago. Air travel, television, computers, phones.

The telephone was invented in 1876, practically old hat a hundred years ago. Air travel was 1903, was around longer than Facebook has been around in 2018. I guess it comes down to your definition of rare, but it's certainly rare enough.
Post reply on HN