Espozo wrote:
So by some freak chance, the computer could actually get the wrong answer for a problem? This seems like it would be extremely problematic...
The possibility of error is inherent in every computing application. There is nothing special about quantum computing in this regard.
There is noise and interference and chosen levels of certainty in all computer engineering. A combination of materials and process is chosen to be as accurate as your application needs.
Internet traffic, hard drives, CDs, transmissions from mars, these things all have error correction schemes, because we
expect some amount of corruption.
In a CPU, usually it's not done with an error correcting algorithm, I don't think (though there is such a thing as
error correcting RAM), but error tolerance level is still a big factor in design. How close can components be put together, how fast can they switch, etc. all of this affects the reliability of its operation, and there is an engineering decision to allow some % of error to happen. (Yes, the computer you're using DOES make mistakes some amount of the time.)
Quantum computing is exactly the same in this regard, do the operation until you meet your target % of confidence.
On the NES, if we're using DPCM while reading the controller, we simply re-read the controller until we're confident we have valid input.
The potential for error is not really that unusual a problem with quantum computing; at the high level, it's the same problem as other kinds of computers; you engineer the tolerance for what you need, create redundancies, checksums, etc. whatever is appropriate for your application.
The thing that is very unusual about quantum computing is just this potential for exponential growth of power, provided we can ever find a practical way to implement it. (I'm not terribly confident we'll ever get there, but I'm glad that people are looking into it, just in case.)