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Where are the discussions on this topic? https://hn.algolia.com/?query=quantum%20google&sort=byPopularity&prefix=false&page=0&dateRange=pastMonth&type=story ht

by 55555 11y ago

Where are the discussions on this topic? https://hn.algolia.com/?query=quantum%20google&sort=byPopularity&prefix=false&page=0&dateRange=pastMonth&type=story https://hn.algolia.com/?query=quantum%20google&sort=byPopula... I would expect, of all places, people on HN to be smart enough to help me understand these news stories. I have no idea what quantum blahblah really means and want to know if this is a real breakthrough or just a news story.

DavidSJ 11y ago
There is real progress on quantum computing: for example http://www.nature.com/nature/journal/v526/n7573/full/nature15263.html http://www.nature.com/nature/journal/v526/n7573/full/nature1... (arXiv preprint for those without Nature subscription: http://arxiv.org/abs/1411.5760 http://arxiv.org/abs/1411.5760), but mostly it's about sustaining quantum entanglement between a handful of qubits. The Google/D-Wave stuff is largely without substance, but makes for nice, breathless media reports. See http://www.scottaaronson.com/blog/?p=2555 http://www.scottaaronson.com/blog/?p=2555 for an explanation of the latest report.
- eru 11y ago
  In contrast to the Google/Martinis stuff, which is full of substance.
fmstephe 11y ago
My understanding is that it is both. This really is a real breakthrough in quantum computing. Specifically for an approach called 'quantum annealing' which is one of many (there is at least one other) possible approaches to quantum computing. This result is a breakthrough in two ways. 1: It demonstrates real quantum effects in the D-Wave computer. It had been hotly debated, by experts in quantum computing, whether the D-Wave actually used quantum effects in its computations. 2: It shows a real speedup for a very specific instance of a very specific algorithm. This is great news, and a very good result, for the people working on the D-Wave. This is just a news story because 1: The D-Wave is much, 100 million times!, faster than the same algorithm running on a conventional computer. But there are algorithms you can run on a conventional computer which are equivalent (If someone could clarify how equivalent they are that would be great) which are as fast as the D-Wave. So they chose an algorithm which is good for the D-Wave and terrible on a classical computer. 2: The problem instance they chose is very artificial and it isn't clear that the speed up wouldn't disappear if they tried to run actual real world instances of the problem. I would conclude that this is a great result. It increases the understanding of quantum computing. That is very exciting. The D-Wave doesn't appear to be practically useful. Yet. (I am not even the beginning of an expert in this, everything I wrote above comes from the link below) http://www.scottaaronson.com/blog/?p=2555 http://www.scottaaronson.com/blog/?p=2555
- hcf 11y ago
  It's probably still time to be dusting off lamport signatures.
  - refset 11y ago
    Ha, yes definitely. Thankfully the state-of-the-art in hash-based crypto has progressed a fair bit since the original lamport signature. The stateless "SPHINCS" signature scheme is looking quite mature already: http://sphincs.cr.yp.to http://sphincs.cr.yp.to Although if you are working with an Event-Sourced architecture you may as well just implement with OTS (One-Time Signature) chains.
- thomasahle 11y ago
  My understanding: The D-Wave machine isn't general quantum computing, but hardware supporting one specific algorithm: quantum annealing. Quantum annealing is similar to Simulated annealing, and if you compare the D-Wave machine to simulated annealing implemented on normal, non specialized, hardware, the D-Wave is 100,000,000 times faster. In principal, even if the hardware only supports one algorithm, this could tell us something about whether quantum computers are really better than normal computers. Unfortunately the D-Wave machine/algorithm is still not much better than simply simulating a quantum machine in normal hardware (Quantum Monte Carlo) and worse than the conventional algorithm by Alex Selby. It's interesting, but it still doesn't shed much light on the important questions.
  - InvisibleCities 11y ago
    One more thing that you didn't mention, which I think is important: if you run simulated annealing on specialized hardware and compare it to the performance of D-Wave's machine, there is virtually no speedup for D-Wave's machine.
  - nickpsecurity 11y ago
    Sort. A counterpoint I read on this topic indicated it might be rigged a bit. The comparison was to an emulation of D-Wave's own annealing process on a single-CPU machine. That's... already an unfair representation of simulated annealing's performance on classical hardware. I'd compare the solution of a problem to optimized algorithms on NUMA machines, GPU clusters, and FPGA clusters that cost whatever D-Wave costs. Given that's all one knows about how it really works past their claims: input X dollars to get Y performance and Z energy-use. ;) Note: One could also compare to performance of single machine with CPU's, GPU's, FPGA's, and/or ASIC's to be more fair. Just needs to be optimal, classical implementation on HW designed for it vs optimal use of D-Wave.
tacos 11y ago
Previous discussion here: https://news.ycombinator.com/item?id=10707442 https://news.ycombinator.com/item?id=10707442
eveningcoffee 11y ago
Here https://news.ycombinator.com/item?id=10698317 https://news.ycombinator.com/item?id=10698317 and also more importantly here https://news.ycombinator.com/item?id=10707442 https://news.ycombinator.com/item?id=10707442 TL;DR: Google researchers demonstrated that DWAVE2X quantum annealing against one classical (i.e. normal computer) algorithm (on one CPU core) - simulated annealing, was asymptotically (i.e. more than just by constant factor) better, but was not against another classical algorithm quantum monte carlo (QMC) that is, the difference was constant. In fact, it was 10^8 times faster and that is generating all the hype. Now, it was mentioned in the paper that Selby algorithm on classical computer would actually produce better results than DWAVE2X but it was not compared against it (maybe because it would minuscule the amazing 10^8 times difference). Also it is worth mentioning that special solutions in silicon (ASIC) are demonstrated to produce about 10^6 faster results compared against the same algorithm on a single CPU core (it does not follow that such speed up is possible for every classical solution).
marcosdumay 11y ago
A mainstream media article about quantum computer that starts with a reference to D-Ware can be safely ignored. Quantum computers (the real kind) are still impractical. People are still working hard to make them bigger, but this still gets harder and harder as the computer size increase. And people still don't know if that's an inherent difficulty of the problem, of if some breakthrough will suddenly make quantum computers easy to make. Or, in other words, there's no visible change for people that is not closely following the area.
stefantalpalaru 11y ago
> I have no idea what quantum blahblah really means and want to know if this is a real breakthrough or just a news story. This should help: http://news.mit.edu/2015/3q-scott-aaronson-google-quantum-computing-paper-1211 http://news.mit.edu/2015/3q-scott-aaronson-google-quantum-co...
lawpoop 11y ago
Believe it or not, the science subreddits often contain high-quality comments that range from beginner/simplest to probably peer-level language.

by 55555 11y ago

DavidSJ 11y ago

There is real progress on quantum computing: for example http://www.nature.com/nature/journal/v526/n7573/full/nature15263.html http://www.nature.com/nature/journal/v526/n7573/full/nature1... (arXiv preprint for those without Nature subscription: http://arxiv.org/abs/1411.5760 http://arxiv.org/abs/1411.5760), but mostly it's about sustaining quantum entanglement between a handful of qubits. The Google/D-Wave stuff is largely without substance, but makes for nice, breathless media reports. See http://www.scottaaronson.com/blog/?p=2555 http://www.scottaaronson.com/blog/?p=2555 for an explanation of the latest report.

eru 11y ago
In contrast to the Google/Martinis stuff, which is full of substance.

fmstephe 11y ago

My understanding is that it is both. This really is a real breakthrough in quantum computing. Specifically for an approach called 'quantum annealing' which is one of many (there is at least one other) possible approaches to quantum computing. This result is a breakthrough in two ways. 1: It demonstrates real quantum effects in the D-Wave computer. It had been hotly debated, by experts in quantum computing, whether the D-Wave actually used quantum effects in its computations. 2: It shows a real speedup for a very specific instance of a very specific algorithm. This is great news, and a very good result, for the people working on the D-Wave. This is just a news story because 1: The D-Wave is much, 100 million times!, faster than the same algorithm running on a conventional computer. But there are algorithms you can run on a conventional computer which are equivalent (If someone could clarify how equivalent they are that would be great) which are as fast as the D-Wave. So they chose an algorithm which is good for the D-Wave and terrible on a classical computer. 2: The problem instance they chose is very artificial and it isn't clear that the speed up wouldn't disappear if they tried to run actual real world instances of the problem. I would conclude that this is a great result. It increases the understanding of quantum computing. That is very exciting. The D-Wave doesn't appear to be practically useful. Yet. (I am not even the beginning of an expert in this, everything I wrote above comes from the link below) http://www.scottaaronson.com/blog/?p=2555 http://www.scottaaronson.com/blog/?p=2555

hcf 11y ago
It's probably still time to be dusting off lamport signatures.
- refset 11y ago
  Ha, yes definitely. Thankfully the state-of-the-art in hash-based crypto has progressed a fair bit since the original lamport signature. The stateless "SPHINCS" signature scheme is looking quite mature already: http://sphincs.cr.yp.to http://sphincs.cr.yp.to Although if you are working with an Event-Sourced architecture you may as well just implement with OTS (One-Time Signature) chains.
thomasahle 11y ago
My understanding: The D-Wave machine isn't general quantum computing, but hardware supporting one specific algorithm: quantum annealing. Quantum annealing is similar to Simulated annealing, and if you compare the D-Wave machine to simulated annealing implemented on normal, non specialized, hardware, the D-Wave is 100,000,000 times faster. In principal, even if the hardware only supports one algorithm, this could tell us something about whether quantum computers are really better than normal computers. Unfortunately the D-Wave machine/algorithm is still not much better than simply simulating a quantum machine in normal hardware (Quantum Monte Carlo) and worse than the conventional algorithm by Alex Selby. It's interesting, but it still doesn't shed much light on the important questions.
- InvisibleCities 11y ago
  One more thing that you didn't mention, which I think is important: if you run simulated annealing on specialized hardware and compare it to the performance of D-Wave's machine, there is virtually no speedup for D-Wave's machine.
- nickpsecurity 11y ago
  Sort. A counterpoint I read on this topic indicated it might be rigged a bit. The comparison was to an emulation of D-Wave's own annealing process on a single-CPU machine. That's... already an unfair representation of simulated annealing's performance on classical hardware. I'd compare the solution of a problem to optimized algorithms on NUMA machines, GPU clusters, and FPGA clusters that cost whatever D-Wave costs. Given that's all one knows about how it really works past their claims: input X dollars to get Y performance and Z energy-use. ;) Note: One could also compare to performance of single machine with CPU's, GPU's, FPGA's, and/or ASIC's to be more fair. Just needs to be optimal, classical implementation on HW designed for it vs optimal use of D-Wave.

tacos 11y ago

Previous discussion here: https://news.ycombinator.com/item?id=10707442 https://news.ycombinator.com/item?id=10707442

eveningcoffee 11y ago

Here https://news.ycombinator.com/item?id=10698317 https://news.ycombinator.com/item?id=10698317 and also more importantly here https://news.ycombinator.com/item?id=10707442 https://news.ycombinator.com/item?id=10707442 TL;DR: Google researchers demonstrated that DWAVE2X quantum annealing against one classical (i.e. normal computer) algorithm (on one CPU core) - simulated annealing, was asymptotically (i.e. more than just by constant factor) better, but was not against another classical algorithm quantum monte carlo (QMC) that is, the difference was constant. In fact, it was 10^8 times faster and that is generating all the hype. Now, it was mentioned in the paper that Selby algorithm on classical computer would actually produce better results than DWAVE2X but it was not compared against it (maybe because it would minuscule the amazing 10^8 times difference). Also it is worth mentioning that special solutions in silicon (ASIC) are demonstrated to produce about 10^6 faster results compared against the same algorithm on a single CPU core (it does not follow that such speed up is possible for every classical solution).

marcosdumay 11y ago

A mainstream media article about quantum computer that starts with a reference to D-Ware can be safely ignored. Quantum computers (the real kind) are still impractical. People are still working hard to make them bigger, but this still gets harder and harder as the computer size increase. And people still don't know if that's an inherent difficulty of the problem, of if some breakthrough will suddenly make quantum computers easy to make. Or, in other words, there's no visible change for people that is not closely following the area.

stefantalpalaru 11y ago

> I have no idea what quantum blahblah really means and want to know if this is a real breakthrough or just a news story. This should help: http://news.mit.edu/2015/3q-scott-aaronson-google-quantum-computing-paper-1211 http://news.mit.edu/2015/3q-scott-aaronson-google-quantum-co...

lawpoop 11y ago

Believe it or not, the science subreddits often contain high-quality comments that range from beginner/simplest to probably peer-level language.