Thursday, December 10, 2015

Not yet truly a quantum computer

I just re-iterated my claim that we have no quantum computer showing a quantum speedup, and now Scott Aaronson comments on the latest hype:
As many of you will have seen by now, on Monday a team at Google put out a major paper reporting new experiments on the D-Wave 2X machine. (See also Hartmut Neven’s blog post about this.) The predictable popularized version of the results—see for example here and here—is that the D-Wave 2X has now demonstrated a factor-of-100-million speedup over standard classical chips, thereby conclusively putting to rest the question of whether the device is “truly a quantum computer.” ...

Thus, while there’s been genuine, interesting progress, it remains uncertain whether D-Wave’s approach will lead to speedups over the best known classical algorithms, ...

But to repeat: even if D-Wave makes all four of these improvements, we still have no idea whether they’ll see a true, asymptotic, Selby-resistant, encoding-resistant quantum speedup.  We just can’t say for sure that they won’t see one. ...

I still have no idea when and if we’ll have a practical, universal, fault-tolerant QC, capable of factoring 10,000-digit numbers and so on.  But it’s now looking like only a matter of years until Gil Kalai, and the other quantum computing skeptics, will be forced to admit they were wrong — which was always the main application I cared about anyway!
It is funny how he is perfectly happy spending his life on quantum computer complexity theory, when there is no proof that there is any such thing as a quantum computer. But when someone like me argues that quantum computers are impossible, then suddenly he wants research to prove me wrong.

It is almost as if he wants to work on something of no practical value, but he does not want anyone saying that it has no practical value.


  1. Roger,

    The explanation is quite simple really. He is merely following his funding and will contort himself into any shape necessary to make certain it continues.

    Now, if he actually HAD to produce any results to stay most normally employed people outside of government funding.. well, that would be an actual motivation to arrive at some kind of conclusion.

    Scarcity is the actual true mother of invention, and fat cats don't chase too many mice. The perpetual motion machine of government funding does not encourage coming to a conclusion, only continuance.

    1. Without all the government funding, he would be stuck asking: "You want cream cheese with that bagel?"