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

Google claims to have proved its supremacy with new quantum computer

telegraph.co.uk

Post reply on HN
Print view View original

191–200 of 237 posts

Re: Google claims to have proved its supremacy with new quantum computer

#191

Post by bawolff »

pclmulqdq wrote: post #188
bawolff wrote: post #186

Earlier quoted context omitted.

When people are hyping something that is probably still 20 years out, i think its safe to say they are trying to sell you something. Quantum computers will be a real (albeit not earth shattering) advance, but we are still far off. Still rather people pump money here than crypto bs.

Quantum computing has been 10 years away for the last 30 years.

I don't think that is true, i imagine most people thought it was much more than 10 years away 30 years ago. I think 30 years ago people still weren't sure if it was physically possible at all.

In the mean time real progress has been made. If we continue at this rate (big if) we will eventually have quantum computers. Just not tomorrow.

Re: Google claims to have proved its supremacy with new quantum computer

#192

Post by fsh »

gaze wrote: post #185
alpineidyll3 wrote: post #120

Earlier quoted context omitted.

No you are missing the fact that if the qubits are coupled the systems fundamental gap has shrunk demanding a lower temperature for the same error rate. You should think more about why your rosy scheme hasn't worked yet if you can't explain that empirically maybe you don't quite understand.

The qubits aren't all coupled all the time. The whole point of a 2-qubit gate is the coupling is controllable. Also -- why is the gap of the bare system important? The whole point of QEC is the creation of a decoherence free subspace. Your model is wrong and you don't understand quantum error correction.

The qubits aren't meant to be coupled, but in practice everything is coupled at some level. I find it plausible that having a system with tons of degrees of freedom on a limited energy scale might make it difficult to isolate all the degrees of freedom from each other.

Re: Google claims to have proved its supremacy with new quantum computer

#193

Post by api »

bawolff wrote: post #191
pclmulqdq wrote: post #188

Earlier quoted context omitted.

Quantum computing has been 10 years away for the last 30 years.

I don't think that is true, i imagine most people thought it was much more than 10 years away 30 years ago. I think 30 years ago people still weren't sure if it was physically possible at all. In the mean time real progress has been made. If we continue at this rate (big if) we will eventually have quantum computers. Just not tomorrow.

I think it’ll be like AI: perpetually 50 years away until some big discovery is made and everyone stops laughing.

For AI it was the “attention is all you need” paper. I’ve been told that for QC it might be error correction that scales but I’m not knowledgeable enough to know if that’s true.

I expect that nuclear fusion will follow the same trajectory of being 50 years away until it’s suddenly 0 years away.

The reality for all these is that steady progress is constantly being made but isn’t visible outside experts in the field. Then it reaches a critical mass and you have the “chatgpt moment.”

Re: Google claims to have proved its supremacy with new quantum computer

#194

Post by mistermann »

Dylan16807 wrote: post #176
mistermann wrote: post #166

Earlier quoted context omitted.

I'm talking about the mind's ability to generate what "is", and "is not". It is a curso no doubt, but it is also sometimes a blessing. But usually it runs unnoticed (or even: denied ) in the background, duffing things up. And when it gets noticed, sometimes really weird things happen.

> And when it gets noticed, sometimes really weird things happen. ....such as? If you have any proof you can probably get a nobel prize.

Everyone "already knows" these things, so no awards or even surprise awaits one.

Re: Google claims to have proved its supremacy with new quantum computer

#195

Post by EvgeniyZh »

deepburner wrote: post #137

Quantum Computing/Information researcher here. This article is largely garbage, the original (~2 month old) paper is surprisingly readable [0] and I suggest you to check it out. Here's my $0.02: The efforts of the Google team is commendable in that they're trying to squeeze as much out of their noisy systems as possible until error correction is here (they need to, to justify their existence after all) and they are a…

I don't agree. I do a bit of QC in my PhD, but my advisor works specifically on error mitigation, and from what I see, we'll soon (maybe a couple of years) be there: we'll have state-of-the-art simulations on quantum computer. There will be classical simulations that will improve on a specific claim, but eventually they'll die out.

But even if it is not true, think how good can be QC without being good enough for quantum error correction. You're saying orders of magnitude improvements are needed to be able to do EC, but I'm sure useful and interesting things can be done with log(QV) of 100, only 5 times more than current record.

Re: Google claims to have proved its supremacy with new quantum computer

#196

Post by typon »

avsteele wrote: post #171
deepburner wrote: post #137

Quantum Computing/Information researcher here. This article is largely garbage, the original (~2 month old) paper is surprisingly readable [0] and I suggest you to check it out. Here's my $0.02: The efforts of the Google team is commendable in that they're trying to squeeze as much out of their noisy systems as possible until error correction is here (they need to, to justify their existence after all) and they are a…

Grover's algorithm seems quite useful, though I'd guess it requires an enormous number of qubits (large unordered database) to be useful.

What class of actually useful algorithms are limited by unordered search?

Re: Google claims to have proved its supremacy with new quantum computer

#197

Post by deepburner »

EvgeniyZh wrote: post #195
deepburner wrote: post #137

Quantum Computing/Information researcher here. This article is largely garbage, the original (~2 month old) paper is surprisingly readable [0] and I suggest you to check it out. Here's my $0.02: The efforts of the Google team is commendable in that they're trying to squeeze as much out of their noisy systems as possible until error correction is here (they need to, to justify their existence after all) and they are a…

I don't agree. I do a bit of QC in my PhD, but my advisor works specifically on error mitigation, and from what I see, we'll soon (maybe a couple of years) be there: we'll have state-of-the-art simulations on quantum computer. There will be classical simulations that will improve on a specific claim, but eventually they'll die out. But even if it is not true, think how good can be QC without being good enough for qua…

You're talking in very vague terms here, what does """interesting""" mean?

Let me give you some numbers. Factorising RSA is order 10^6 logical qubits (and I'm being charitable here), simulating FoMoCo is around 10^7. The state of the art error correction is around (again, charitably) 10^3 physical qubits per logical qubit at the moment, that gives us 10^9-10^10 qubits necessary for the simplest quantum application. We're at order 100 right now.

Peter Shot thinks that error correction can go down to 100 physical-per-logical, that's an order of magnitude shaved off there, but the algorithm itself is pretty basic, i don't see it getting any better there. Simulation algorithms have much better odds in seeing improvements as I think the gates used there are rather non-standard and have avenues for better gate compilation techniques.

Re: Google claims to have proved its supremacy with new quantum computer

#198

Post by gaze »

fsh wrote: post #192
gaze wrote: post #185

Earlier quoted context omitted.

The qubits aren't all coupled all the time. The whole point of a 2-qubit gate is the coupling is controllable. Also -- why is the gap of the bare system important? The whole point of QEC is the creation of a decoherence free subspace. Your model is wrong and you don't understand quantum error correction.

The qubits aren't meant to be coupled, but in practice everything is coupled at some level. I find it plausible that having a system with tons of degrees of freedom on a limited energy scale might make it difficult to isolate all the degrees of freedom from each other.

Yeah but these are the most basic of basic problems in QC and people would be discarding approaches that didn’t have potential solutions to this issue. In superconducting QCs, neighboring qubits are not necessarily even resonant, and are in their own little metal boxes. With neutral atoms, you have extremely long lived internal states that barely couple to the environment, and the atoms are macroscopic distances from each other.

Re: Google claims to have proved its supremacy with new quantum computer

#199

Post by jabbany »

dataflow wrote: post #89
jabbany wrote: post #19

Earlier quoted context omitted.

One would be the direction of entropy. Breaking the stick is not "particularly fascinating" because you're going in the direction of increasing entropy. However, _putting it back together_ is. In the simulation it takes no more effort to go one way or the other, while you probably cannot put the stick back together no matter how hard you tried. A quantum question that is "interesting" would also be similar to finding…

I really love this comment -- it "feels" like the right criterion -- but I guess I'm wondering what criteria (if any) researchers actually use right now. Do they have any criteria for this?

I'm not a quantum computing researcher but I have friends who work on it. The way they've described this to me (answering a question around "how does one know what quantum stuff is bs") was that it's largely a set of known "hard" questions where we've empirically found hard for classical computing but we maybe could solve with quantum. In a way it's been described as similar to crypto primitives or P?=NP problems where we don't know for certain why it's harder one way vs the other but it seems to be the case based on our current knowledge. It could possibly (but unlikely) be the case that we eventually find classical solutions that are just as fast.

They don't seem worried about this though, since at least research-wise just working with quantum as a new tool to solve problems itself is intellectually interesting (and the "solves classically challenging problems" is a good way to frame the work's potential impact to general audiences). Also, there's other supposed uses of quantum beyond just computing, like for communication etc.

Re: Google claims to have proved its supremacy with new quantum computer

#200

Post by ted_dunning »

erikaww wrote: post #177
deepburner wrote: post #137

Quantum Computing/Information researcher here. This article is largely garbage, the original (~2 month old) paper is surprisingly readable [0] and I suggest you to check it out. Here's my $0.02: The efforts of the Google team is commendable in that they're trying to squeeze as much out of their noisy systems as possible until error correction is here (they need to, to justify their existence after all) and they are a…

I'm not educated on QC. But wouldn't Grover's algorithm be very useful? I believe it provides a sqrt(n) time search. For QC to be useful,it just needs to make common utilities very fast. I should look more into QC. It would be cool if it could speed all computation up. I understand there are algorithms that it could execute that a classical composer could not, but I wonder if it could eventually he like just faster h…

Most general purpose computing is based on algorithms that are essentially O(n).

What that means is that they are a constant times the cost of simply reading the input. Often, the computation is actually cheaper.

Quantum computing might make some computations have a smaller theoretical constant, but it is almost certain that the practical constant ($/bit of input) will be much, much worse due to scale.

Right now, only very specialized computations look like they will ever have any speedup. And even that is only maybe, in practice.

Post reply on HN