Comments by "Lawrence D’Oliveiro" (@lawrencedoliveiro9104) on "Current State of Quantum Computing - Computerphile" video.

  1. There might be one in this box. Or there might not. You can’t tell until you open it.
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  2. Remember the old analog computers? Back in the early 20th Century, analog computers could solve certain problems faster than digital machines, but with less precision. They fell out of favour as digital computers became able to match them in speed while maintaining greater precision. Also they were never any good at number-theoretic problems (e.g. factorization, code-cracking). Quantum computers are basically a reboot of the old analog-computer idea. The kinds of problems they can solve are in the same class -- physical simulations and optimization -- where speed is more important than precision. And they are similarly useless at number-theoretic problems.
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  3. Actually, every computer is “quantum”. Consider that the behaviour of the transistor (charges tunnelling across an energy barrier, “holes” (missing electrons) behaving just like positively-charged electrons) can only be explained in terms of quantum theory.
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  4. Triple meaning. “Current”!
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  5. Because the “parallel worlds” idea doesn’t really help explain quantum theory.
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  6. Why parallel worlds is useless: because it just replaces a superposition of states with a superposition of alternative realities. What makes one “plainer” than the other (Which is what “explaining” is supposed to do)?
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