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Google's and IBM's previous "quantum supremacy" demonstrations were quickly crushed by improved classical simulations. Let's see if it survives this time.

• dataflow 3y ago
  Would you have any links handy for those?
• lbourdages 3y ago
  The main issue I had with their demonstrations were that the problems they chose were essentially "let's show that a quantum computer is better at being a quantum computer than a classical computer". Obviously they are, just like I'm better at being a human than ChatGPT is. I'm not saying they suck, but to proclaim that "quantum computers are superior" you need an actual use-case, IMO.
  • deleted 3y ago
    [deleted]
  • refulgentis 3y ago
    It's absolutely non-obvious, I'm dead serious. As far as I've understood keeping up over the years, there's a credible argument from a respected academic in the QC community that quantum computing is impossible.
    • lbourdages 3y ago
      Do you have a link handy? You've piqued my curiosity!
      • refulgentis 3y ago
        Here's an exhaustive covering: https://www.scottaaronson.com/democritus/lec14.html https://www.scottaaronson.com/democritus/lec14.html I would have picked it up in bits and pieces from blogs over years, here's an attempt to render that useful that is surely nitpickable: TL;DR: there's two types of caring about Google's claims of quantum supremacy: 1. HN tends to assume these articles are about breakthrough in _product usefulness_ and then tsk tsk about lack of impact. c.f. top comment currently gravely noting after reading the paper, its too noisy and a long way off. 2. The papers are about demonstrating _there is quantum computing at all_, the interest in the people in the know is about settling that question, the raw strongman feat isn't particularly interesting.
        • nier 3y ago
          From the article linked by parent: «To summarize, I think that arguing with skeptics is not only amusing but extremely useful. It could be that quantum computing is impossible for some fundamental reason. So far, though, I haven't seen an argument that's engaged me in a really nontrivial way.» «Very little of what we do in theoretical computer science is directly connected to a practical application. That's just not what we're trying to do. Of course, what we do has applications, but indirectly. We're trying to understand computation. If you take that as our goal, then it seems clear that starting from the best physical theories we have is a valuable activity. If you want to ask a different question, such as what we can do in the next five to ten years, then, that's fine. Just make it clear that's what you're doing.»
          • refulgentis 3y ago
            This shouldn't leave anyone with the impression they are cranks. Scott's claim in this lecture is he hasn't yet found making a counter argument "really nontrivial" To wit, the article names Leonid Levin and Oded Goldreich as the primary skeptics. Leonid has 10K citations, 2012 Knuth Prize, 37 h-index. Oded has 63K citations, 2017 Knuth Prize, 95 h-index. What Scott Aaronson considers "really nontrivial" is far beyond our comprehension, and he's making a claim about synthesizing an counterargument, not settling the entire argument.
    • dekhn 3y ago
      it's not impossible (from a theoretical, and possibly physical perspective) but it's likely that there are no problems which would motivate the necessary investment to demonstrate a QC doing something useful which we couldn't also do in reasonable time on a classical supercomputer. Kind of like fusors: sure, you can do nuclear fusion in your garage but you're putting in far more energy than you are generating.
  • hiddencost 3y ago
    They're not claiming quantum computers are superior. They're claiming they have a device which can do something that you couldn't do with a classical computer. A very narrow claim. It is a big deal to academics, and a number of people here are close to that world and interested.
• cohomologo 3y ago
  True, but as someone who works on quantum physics using classical computers and loves to see classical computers simulating increasingly hard quantum problems, these "crushings" were still only done on classical computers in a way that would scale exponentially with the number of qubits. Even then, I believe the classical simulations to beat google's 53 qubit device were never actually performed -- it was shown that they could be performed quickly with petascale memory but actually doing it would be a huge expense. Add a dozen more qubits and even the hypothetical classical challengers fall off quickly...