The road towards quantum computers have so many obstacles, which are deeply different and more challenging than the problems that we had with the development of classical computers. There are reasons to believe that quantum computers with a "large enough" number of qubits and low decoherence to be actually useful.

Yet, there are so many investments and there's so much research around that to suggest that the whole community believes that it's certain that we will have quantum computers sooner or later.

Where does this belief come from? Are there factual, scientific arguments to support that?

  • $\begingroup$ Love the question! Somewhat of a tangent, but I also think it's fascinating how the theory of quantum computers has advanced classical algorithms. Even if a large quantum computer is never physically realizable, the insights gleaned from studying quantum algorithms will improve classical ones $\endgroup$
    – C. Kang
    Sep 20 '20 at 15:37
  • $\begingroup$ Isn't this a bit circular? If you spend money and do research you will naturally make quantum computers practical to some extent. If you don't spend that money, then they will never be practical. $\endgroup$
    – user157879
    Sep 21 '20 at 2:03
  • $\begingroup$ if it works there is a big payoff, and there are no widely accepted compelling reasons to think it won't work, eventually. I'd say quantifying whether the current hype/amount of investments in the subject is justified by the science is quite hard and probably largely opinion-based (and based more on sociology than physics/math). $\endgroup$
    – glS
    Sep 21 '20 at 14:24

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