| ▲ | dekhn 3 days ago |
| quantum computers can (should be able to; do not currently) solve many useful problems without ever being able to factor primes. |
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| ▲ | xscott 3 days ago | parent | next [-] |
| What are some good examples? The one a few years ago where Google declared "quantum supremacy" sounded a lot like simulating a noisy circuit by implementing a noisy circuit. And that seems a lot like simulating the falling particles and their collisions in an hour glass by using a physical hour glass. |
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| ▲ | dekhn 3 days ago | parent | next [-] | | The only one I can think of is simulating physical systems, especially quantum ones. Google's supremacy claim didn't impress me; besides being a computationally uninteresting problem, it really just motivated the supercomputer people to improve their algorithms. To really establish this field as a viable going concern probably needs somebody to do "something" with quantum that is experimentally verifiable but not computable classically, and is a useful computation. | | |
| ▲ | SAI_Peregrinus 3 days ago | parent [-] | | That is equivalent to proving BQP ≠ P. We currently don't know that any problem even exists that can be solved efficiently (in polynomial time) by quantum computers but not by classical computers. |
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| ▲ | EvgeniyZh 3 days ago | parent | prev [-] | | I wrote a long-ish comment about what you can expect of QC just yesterday https://news.ycombinator.com/item?id=42212878 | | |
| ▲ | xscott 2 days ago | parent [-] | | Thank you for the link. I appreciate the write-up. This sentence though: > breaking some cryptography schemes it not exactly the most exciting thing IMHO You're probably right that we'll migrate to QC-resistant algorithms before this happens, but if factoring was solved today, I think it would be very exciting :-) | | |
| ▲ | EvgeniyZh 2 days ago | parent [-] | | I think it would be very __impactful__, but it is not really useful for humanity, rather opposite. | | |
| ▲ | xscott 2 days ago | parent [-] | | Who knows. "It's difficult to make predictions, especially about the future", but it might be a good thing to accelerate switching to new crypto algorithms sooner, leaving fewer secrets to be dug up later. |
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| ▲ | Eji1700 3 days ago | parent | prev [-] |
| Yeah I think that's the issue that makes it hard to assess quantum computing. My very layman understanding is that there are certain things it will be several orders of magnitude better at, but "simple" things for a normal machine quantum will be just as bad if not massively worse. It really should be treated as a different tool for right now. Maybe some day in the very far future if it becomes easier to make quantum computers an abstraction layer will be arrived at in some manner that means the end user thinks it's just like a normal computer, but from a "looking at series of 1/0's" or "looking at a series of superimposed particles" it's extremely different in function. |
