9 ms·
Turn down the quantum volume
- nrclark 7y agoNot trolling, but curious - do quantum computers do anything useful yet?
- obi1kenobi 7y agoThere are some interesting ideas around using quantum computers for verifiably-random numbers, including a proposal from Scott Aaronson himself: https://www.quantamagazine.org/how-to-turn-a-quantum-computer-into-the-ultimate-randomness-generator-20190619/ https://www.quantamagazine.org/how-to-turn-a-quantum-compute...
- fsh 7y agoI just don't get why you would want to use a quantum computer to generate random numbers. Hardware-RNGs are cheap and have existed for decades. Your CPU probably has one built-in. Some even rely on quantum effects such as shot noise, but where is the advantage over using say thermal noise of a resistor? Both are completely unpredictable.
- obi1kenobi 7y agoIf you want random numbers just for yourself, all of the approaches you mention are fine to use. The difference is that by using a quantum computer, one could generate random numbers and convince others that the numbers are actually random and not rigged.
- baddox 7y agoMy impression is that we've recent just maybe gotten to the point where someone has proven that they have a computer that actually is doing quantum computing for something that would be exponentially slower to do on a classical computer. My understanding is that this is what Google has recently claimed to have done, and before that no one had published any serious claims that they had done real quantum computing. As always, Scott Aaronson has a solid article, some of which I can understand: https://www.scottaaronson.com/blog/?p=4317 https://www.scottaaronson.com/blog/?p=4317
- dekhn 7y agoNo. There have been some interesting quantum simulation papers but nobody has shown anything yet that is revolutionary. This is promising work that may be interesting in the future: https://arxiv.org/pdf/1902.10171.pdf https://arxiv.org/pdf/1902.10171.pdf This also looks like it could be interesting: http://meetings.aps.org/Meeting/MAR20/Session/W17.7 http://meetings.aps.org/Meeting/MAR20/Session/W17.7 (Gurobi is a CPU solver for integer and linear programming problems, which are some of the most useful to solve quickly. There is also: https://ai.googleblog.com/2016/07/towards-exact-quantum-description-of.html https://ai.googleblog.com/2016/07/towards-exact-quantum-desc...
- kaiabwpdjqn 7y agocan you give an example of a linear programming task that is not currently practical to solve on classical computers but could become so with a huge speed up?
- MrK93 7y agoRouting, TSP, scheduling, they all benefit from huge speed ups.
- kaiabwpdjqn 7y agoI guess. But we already optimize these things. Without any specific domain in mind, I wonder how much better we could get. Like maybe amazon could find the global minimum cost to route, but right now it’s getting pretty darn close. Or maybe that’s entirely naive and the potential for finding faster solutions to real time problems is huge
- dekhn 7y agoit is huge. that's the only reason people are motivated to implement QC- because in principle then we can break crypto, do QM much faster, solve intractable problems, etc. Day-to-day, we're not really blocked on QC to get important work done.
- 6nf 7y agoAlmost but not yet
- lisper 7y agoAlmost? What have they done that you would consider "almost" useful?
- 6nf 7y agoThey have proved that it's physically possible for quantum computers to do things that classical computers can not. In other words, they have proved that quantum supremacy is real.
- lisper 7y agoNo, they haven't. There is nothing that a QC can do that a CC cannot. CC's are universal. They can compute any computable function. What QC's can do in theory is perform some computations much faster than a CC can. One QC has actually done that, but the computation was of a function that cannot reasonably be called "useful". The potentially useful things that QCs can do is speed up factoring, protein folding analysis, simulation of chemical reactions... no QC has come anywhere near doing any of those things.
- 6nf 7y agoYou don’t agree with Google’s November paper then I guess? You KNOW what quantum supremacy means. Please don’t nit pick my layman’s description we are all adults here. You know what I meant.
- lisper 7y agoI'm not taking issue with your definition of quantum supremacy, I'm taking issue with your (implied) definition of "almost useful". Personally, I don't consider the demonstration of quantum supremacy in and of itself to be useful. It is very interesting, but IMHO it is not (yet) fair to say that QCs have done anything useful, even if you hedge with "almost".
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- klingonopera 7y agoI have absolutely no clue about quantum computing, but I remember this from two years ago. Haven't heard anything since. Is this relevant? Does anyone have thoughts on this? https://spectrum.ieee.org/tech-talk/telecom/security/china-successfully-demonstrates-quantum-encryption-by-hosting-a-video-call https://spectrum.ieee.org/tech-talk/telecom/security/china-s...
- chrispeel 7y agoQuantum encryption as in the IEEE Spectrum article is not the same thing as quantum computing, which is what the original post is about. So no, not relevant Even so, HN is all about the non-relevant stuff, so I'll give my two bits on quantum encryption, which is that it is dramatically easier than quantum computing for short distances, yet even so its not practical to replace our entire internet such as to enable its use. And until the quantum computers are built, there's no need for it
- dreamcompiler 7y ago> And until the quantum computers are built, there's no need for it. Disagree. One of the coolest things about quantum encryption is that any attempt to eavesdrop a communication is instantly detectable. This is extremely useful for communication between conventional computers.
- brian-armstrong 7y agoSure, they've led to lots of grants and work for grad students.
- kragen 7y agoHi! What do you think the postquantum security story for Bitcoin looks like? That is, if someone starts being able to build big quantum computers, what vulnerabilities does that create in Bitcoin, and is there a way we can solve them in time to keep the whole system from collapsing?
- core-questions 7y agohttps://www.dwavesys.com/applications https://www.dwavesys.com/applications is worth looking at, they quote 200 different applications for their system. Truly useful as in profitable, maybe not yet, but it's still early days - it would be like asking Von Neumann how he plans to handle microtransactions
- iainmerrick 7y agoFrom what I’ve read about Von Neumann, he’d probably take a decent stab at answering that!
- core-questions 7y agoOh, no doubt, and I bet you could get someone from any of the current QC companies to go hog wild with ideas over a beer or two, but in practical reality what matters is execution and manufacturing - something that Honeywell, Google, et. al. have been scant on but seems to be core to what D-Wave is doing.
- amelius 7y agoOr in other words: fire your marketing department.
- shireboy 7y agoWhat he advocates makes sense. Marketing for classical computers used to make hay about how fast the CPU was in Khz, Mhz, Ghz. This is done less now since people recognize that is just one of several factors when comparing devices. It's still mentioned, just alongside the architecture, ram, GPU, etc. It can be hard to compare if you're not up on all the differences.
- vortico 7y agoPeople now buy CPUs and GPUs based on primarily one index: how many fps their favorite games can run at their desired resolution and quality. So manufacturers of QCs should do the same by specifying what problems at what sizes their hardware is best at solving.
- ggm 7y agoI think the function should be something like "number of stable QBits which can demonstrably add to an implementation of Shors algorithm" So it excludes DWave, and the unstable QBits, and focusses on a specific known problem which (I believe) gets closer to e.g. breaking useful real-world unknown value RSA, rather than simply being "how big it is" As long as a graphics card is just painting pixels its mainly about entertainment. When somebody says "this graphics card can now exhaustively search 20 letter password strings against a known hash string and find your passphrase in under 30 seconds" then its a real issue.
- core-questions 7y agoWhy does any reasonable function need to exclude D-Wave by default? Aren't they the only company with an actual, publicly-accessible, realtime production system you can use? I know it's not gate model, but it does compute using quantum effects, and so any reasonable model of performance has to include for this sort of system. IIRC D-Wave doesn't like single digit performance indicators, so they're aligned with Aaronson on this for once.
- fsh 7y agoThere is no indication (not even from the theory side) that the D-Wave approach can achieve any speed-up over a classical computer. This is one of the reasons why Aaronson and many others in the field are not taking them seriously. Sure, they will gladly sell you a system, but the whole architecture will most likely never be useful for anything.
- correlaterdude 7y ago> There is no indication (not even from the theory side) that the D-Wave approach can achieve any speed-up over a classical computer. You're wrong about the theory side of things[1, 2], by the way. The discussion around adiabatic quantum computing is weirdly politicized. It's true that D-Wave's computer isn't a universal quantum annealer; but in theory such a thing is equivalent to a gate-model computer. [1] https://arxiv.org/pdf/1611.04471.pdf https://arxiv.org/pdf/1611.04471.pdf [2] https://iopscience.iop.org/article/10.1088/0256-307X/35/11/110303 https://iopscience.iop.org/article/10.1088/0256-307X/35/11/1...
- darawk 7y agoWhy isn't it defined in terms of the solvable problems? This quantum computer can factor an n-bit composite number seems like a fairly objective test.
- fsh 7y agoIt's a marketing problem. Shor's algorithm seems to be extremely hard to run without cheating by "optimizing" the program on a classical computer that already knows the answer. Nobody wants to announce that they barely managed to factor 21 or something like that, while at the same time trying to convince the public that their system is somehow superior to classical computers.