Can anyone recommend a few videos, papers, or books that "start at the beginning" for how quantum computing works--the physics parts like entanglement. I'm a computer scientist, so I'm good with the algorithm/programming aspects. Should I start with quantum annealing? Ideally I guess I'd like some pointers to good approachable resources on the ways qubits are made, maintained, written to and read from--start me off at the quantum version of the transistor. Thanks HN.
Google claims to have proved its supremacy with new quantum computer
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Re: Google claims to have proved its supremacy with new quantum computer
#132Earlier quoted context omitted.
Quantum computing feels like nucleair fusion. Been hearing about how its going to change the world since I was kid.
Well, in fairness, I could say the same about solar, improved batteries, etc.
> solar, improved batteries
Neither of those sounded as sexy (i.e hyped) to me a nuclear fusion and quantum computers.
Re: Google claims to have proved its supremacy with new quantum computer
#133Earlier quoted context omitted.
You really just answered this yourself: > Assume a computer would need several minutes to simulate everything that would've happened in the stick. I clearly got the output faster than a computer (and with more precision), so does this imply I'm doing anything particularly fascinating? You assert that you have output faster than a computer with more precision. However, you do not have any empirical data, just observab…
I don’t think you guys are tackling this right. You can observe the stick breaking to absurd precision, even using an electron tunneling microscope, and produce immense amounts of data about the sticks state at every point in the breaking and afterwards faster than a computer can simulate breaking the stick. The key is the stick breaking and it’s observation at any level of detail happens in parallel with all aspects…
But the comparison is not fair.
Yes the electron microscope can image a lot of details "in parallel" but not all details from all angles, all internal microfractures. You can't easily measure all temperature gradients in all cubic nanometers of the material etc etc.
The simulation is slow because it works at that level and thus as a side effect will also give you that output.
Obviously if you don't need all that information you may find another route to arrive at the results you want
Re: Google claims to have proved its supremacy with new quantum computer
#134Google's and IBM's previous "quantum supremacy" demonstrations were quickly crushed by improved classical simulations. Let's see if it survives this time.
The main issue I had with their demonstrations were that the problems they chose were essentially "let's show that a quantum computer is better at being a quantum computer than a classical computer". Obviously they are, just like I'm better at being a human than ChatGPT is. I'm not saying they suck, but to proclaim that "quantum computers are superior" you need an actual use-case, IMO.
It's absolutely non-obvious, I'm dead serious. As far as I've understood keeping up over the years, there's a credible argument from a respected academic in the QC community that quantum computing is impossible.
Re: Google claims to have proved its supremacy with new quantum computer
#135Dumb question: Say I have a wooden stick and I break it in half in less than a second. Assume a computer would need several minutes to simulate everything that would've happened in the stick. I clearly got the output faster than a computer (and with more precision), so does this imply I'm doing anything particularly fascinating? I assume the same scenario is possible to concoct for a quantum computer. I assume it wou…
Your wooden stick is dedicated hardware for computing the behavior of wooden sticks. Fascinating? Pretty subjective—but one of the best concrete proxies we have for "fascination" is "economic value" (cf OpenAI's AGI definition). Is it going to make (or save) you a lot of money to quickly find out how that stick broke? Probably not.
I think you can make the case that, for example, going out, taking a stick from a forest, breaking it and record the sound will be much more economical than trying to simulate a realistic stick breaking sound -- in particular in developer time trying to model sticks and wood breaking sounds in a convincing way (suppose we need say an art asset for a game).
It's something complexity theory isn't well prepared to tackle, at least on first look. Complexity theory doesn't take into account the cost of devising an algorithm itself. And complexity theory usually only is interested in asymptotic behavior -- different in both ways from what we have (n=1 and algorithm cost). I think simulations win only when there are significant gains to be had over just doing it in real life, i.e. when you are only interested in a simple aspect that can be summarized by a model, or when for some reason the real life event uses a lot of energy or costs significantly. An extremely accurate simulation of wood and wood breaking, and sound, I think would be quite computationally costly -- the wood is already very complex (not as complex as the base atomic reality -- you probably don't need to model every single atom -- but still very complex). Sticks are cheap, and breaking a stick is easy. Breaking the stick doesn't seem to take much energy, and realistically stick breaking itself (although perhaps not stick collecting) comes out ahead energetically!
It gets quite complicated quickly, and it really depends on what you want to model, but I think it's interesting to see when and if simulations are advantageous (for example, you could take the cost of raising a tree into account, or not! is the stick "free" because it would grow and decay anyway?). I think in the long term many things can be simplified into what we're interested, so models increasingly win. But realistically (in our limited lives and limited universes :)) I think there will always be a place for physical experimentation, taking pictures of sticks and recording the sound as they break. (and hopefully our relationship with trees and sticks itself still lasts for a long time...)
I say that as someone who really enjoys modelling nature! :) I think modelling and trying to recreate natural process (sometimes with an artistic touch as well) is a great way to understand and appreciate the wonders of the universe.
Note: Also, even with ideal reversible 0-cost computation, there's likely to be some kind of polynomial time overhead to 1:1 simulation of reality. This can be enough to justify experimentation instead of simulation, in some cases, when your model itself isn't a significant simplification over reality.
Re: Google claims to have proved its supremacy with new quantum computer
#136> He said: “This is a very nice demonstration of quantum advantage. While a great achievement academically, the algorithm used does not really have real world practical applications, though. > “We really must get to utility quantum computing – an era where quantum computers with many thousand qubits actually begin to deliver value to society in a way that classical computers never will be able to.” This seems to be t…
Quantum computing feels like nucleair fusion. Been hearing about how its going to change the world since I was kid.
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Re: Google claims to have proved its supremacy with new quantum computer
#137Quantum 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 aware of the shortcomings of the paradigm. But personally I don't see anything useful coming out until error correction and number of qubits are improved many orders of magnitude to have fault tolerant QC. The jury is still out on their utility once realized; Shor's algorithm is an obvious one followed by quantum simulation algorithms that might benefit chemistry and fundamental physics, but it's not as big of a silver bullet as we thought before for simulation. Maybe someone can tell me what fast prime factorization is good for besides breaking encryption.
Also IBM released a paper[1] recently making similar claims ("quantum advantage without complete error correction") which got obliterated by 2 back to back papers [2,3] that did what they did for much cheaper on a classical computer.
[0]: https://arxiv.org/pdf/2304.11119.pdf
[1]: https://www.nature.com/articles/s41586-023-06096-3
Re: Google claims to have proved its supremacy with new quantum computer
#138I know nothing about quantum computing, but when I read "does X instantly when rivals need 47 years", I immediately think about it being abused for brute forcing passwords and encryption keys. Would it be possible?
Government institutions have already been instructed to start using quantum computer safe encryption algorithms. Internationally, governments have been storing tons of encrypted data that they can’t currently decrypt because they expect to be able to decrypt it soon using quantum computers. There are already quantum computer safe encryption algorithms that have been released to the public. I don’t know exactly how th…
sha256 is a hash algo. you probably meant something else?
Re: Google claims to have proved its supremacy with new quantum computer
#139So it can generate lots of random numbers very fast... cool. /s
Re: Google claims to have proved its supremacy with new quantum computer
#140Earlier quoted context omitted.
Your wooden stick is dedicated hardware for computing the behavior of wooden sticks. Fascinating? Pretty subjective—but one of the best concrete proxies we have for "fascination" is "economic value" (cf OpenAI's AGI definition). Is it going to make (or save) you a lot of money to quickly find out how that stick broke? Probably not.
I think you can make the case that, for example, going out, taking a stick from a forest, breaking it and record the sound will be much more economical than trying to simulate a realistic stick breaking sound -- in particular in developer time trying to model sticks and wood breaking sounds in a convincing way (suppose we need say an art asset for a game). It's something complexity theory isn't well prepared to tackl…
Complexity theory doesn’t handle it, but that’s why I didn’t use complexity theory. Economics handles it fine: no one’s ever paid you or anyone else to do a wood-breaking simulation at a sufficient physical level of detail to capture the sound accurately, so the comparative savings on it aren’t economically valuable.