4 ms·

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

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.

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.