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> there are also no real signs that a quantum computer will beat a "classical" computer at anything any time soon John Martinis' group is planning to do that w

> there are also no real signs that a quantum computer will beat a "classical" computer at anything any time soon John Martinis' group is planning to do that within the next two years [1][2]. Ten years might be realistic for solving useful problems faster and cheaper, but the esoteric speedups are right around the corner. 1: https://arxiv.org/abs/1608.00263 https://arxiv.org/abs/1608.00263 2: https://www.youtube.com/watch?v=kgMWommXxU8 https://www.youtube.com/watch?v=kgMWommXxU8

YZF 10y ago
Just watched the talk. Definitely an interesting direction. One question I'd have is whether quantum simulation is indeed the fastest way to solve the quantum speckle problem on a classical computer. The other related thing to think about is whether the output of a quantum speckle computer can only be explained by the large state space and quantum mechanics or whether there are alternative explanations. So definitely an interesting direction but even if they're successful we're still not quite there. When we have a quantum computer doing useful work with exponential speedup over classical computers that would be something and even then we only have a very limited set of algorithms at the moment.
- Strilanc 10y ago
  > whether quantum simulation is indeed the fastest way to solve the quantum speckle problem on a classical computer. They give arguments for this in the paper. Intuitively, if there's some fast way to classically sample a random quantum circuit then that means most quantum circuits should be easy to simulate classically. But that doesn't seem to be the case: we don't have algorithms that go fast on most circuits but go slow in highly specialized cases. It's the other way around. > whether the output of a quantum speckle computer can only be explained by the large state space and quantum mechanics or whether there are alternative explanations. Given that all the engineering was based on quantum mechanics, it would be very surprising if the machine worked based on something else. It's quite difficult to make things accidentally work like that. It'd be like trying to build a car, confirming it can take you from place to place, then realizing that actually you made a hang-glider by accident.

YZF 10y ago

Just watched the talk. Definitely an interesting direction. One question I'd have is whether quantum simulation is indeed the fastest way to solve the quantum speckle problem on a classical computer. The other related thing to think about is whether the output of a quantum speckle computer can only be explained by the large state space and quantum mechanics or whether there are alternative explanations. So definitely an interesting direction but even if they're successful we're still not quite there. When we have a quantum computer doing useful work with exponential speedup over classical computers that would be something and even then we only have a very limited set of algorithms at the moment.

Strilanc 10y ago
> whether quantum simulation is indeed the fastest way to solve the quantum speckle problem on a classical computer. They give arguments for this in the paper. Intuitively, if there's some fast way to classically sample a random quantum circuit then that means most quantum circuits should be easy to simulate classically. But that doesn't seem to be the case: we don't have algorithms that go fast on most circuits but go slow in highly specialized cases. It's the other way around. > whether the output of a quantum speckle computer can only be explained by the large state space and quantum mechanics or whether there are alternative explanations. Given that all the engineering was based on quantum mechanics, it would be very surprising if the machine worked based on something else. It's quite difficult to make things accidentally work like that. It'd be like trying to build a car, confirming it can take you from place to place, then realizing that actually you made a hang-glider by accident.