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What you say is true, but apparently, in the case of quantum computers there seem to be some fundamental issues. I remember reading two-three years ago an argum
by GTP 2y ago
What you say is true, but apparently, in the case of quantum computers there seem to be some fundamental issues. I remember reading two-three years ago an argument by a professor of Mathematics against the feasibility of having quantum computers able to break classic public key cryptography (so, admittedly, not against quantum computers in general but only against a specific, but very important, use case). Unfortunately, I already tried finding it again on the Internet but couldn't.
What I vaguely remember among the points he was bringing to the table, was an argument about the amount of shielding you need to have the required amount of qbits to break current RSA to remain coherent long enough for the factorization to complete. He somehow (I don't remember how) showed that this translated to having a result with precision up to a certain decimal place. Meanwhile, the most accurate laws of physics that we know of have a precision that stop a couple of decimal digits before that. Therefore, in his argument, having a quantum computer that is able to break RSA (I don't remember if it was for 2048 or 4096 bit keys) would enatil improving our understanding of physics by two orders of magnitude.
Now, this doesn't mean that this is impossible, and new error correction techniques can change the situation. But, this is to say that here we are at a very different level than having a better version of vaccum tubes or drums.
Personally, I don't say that we will never ever have quantum computers. But I think that some skepticism is granted. Expecially when we hear claims that those are around the corner.
- pjs_ 2y agoThese kind of arguments - that physics will somehow magically forbid us from scaling up quantum computers - are exactly why Google does these experiments on larger and larger chips. If the skeptics are right, we expect their systems to reach some kind of wall where the machine does not behave as anticipated by quantum computing optimists. So far we have not hit any such wall, the machine behaves exactly the way it is supposed to (with predictable error rates etc) and the Google results are on the far side of various thresholds that were believed challenging or impossible by the more skeptical end of the community.
- GTP 2y ago> physics will somehow magically forbid us from scaling up quantum computers Not magically >with predictable error rates etc This isn't my field of expertise, but my understanding is that this is precisely the issue: these predictable error rates are predicted to be a deal-breaker for the amount of qbits that are needed to break RSA with today's commonly-used key lengths. In my view, the fact that the error rates appear to match predictions so far, only sustain this point. A reason to be optimistic could be that sometimes we get to hear about new promising error-correction techniques though. We'll see how future development goes, in the end it is hard to predict what will happen. But this is also why I think we should be more careful in claiming that quantum computer will break classical cryptography in the short to medium term.
- fluoridation 2y ago>So far we have not hit any such wall On the contrary. The wall in question is "can the computer compute the result we need correctly and efficiently?" So far no QC has climbed over that wall.