Re: COMPUTERS; Quantum Computers

Anders Sandberg (nv91-asa@nada.kth.se)
Thu, 26 Dec 1996 14:13:35 +0100 (MET)


On Wed, 25 Dec 1996, John K Clark wrote:

> The short answer is that although a conventional computer could (probably)
> solve any problem a Quantum Computer could if it had enough time, a small
> Quantum Computer, if a practical one could ever actually be made, could solve
> problems almost instantly that would take a conventional computer, even a
> Nanocomputer, many billions of years to solve. I hope you're not asking me
> what changes this would bring to the world because I have no idea, but I
> don't see how a machine of such cosmic power could leave the Universe
> unchanged.

My guess is that beside the obvious uses for high-performance computing,
molecular modelling (there are many obvious nanotech applications for
this, and it might provide a strong impetus to develop nanotech just to be
able to build good quantum computers) and code cracking, I think the truly
awesome application might be AI. I haven't got the faintest idea of how to
implement AI in a quantum computer, but I think it could be tremendously
more efficient than on a conventional computer. Hmm, I wonder what
happens if we move to quantum neural networks...

> Most of the following is a rehash of stuff I sent to the list
> in the past year.

Hmm, maybe this is a good time for us to do this on other subjects too? A
kind of 'end-of-the-year' summary for all of us?

> It gets even wilder, because the quantum mechanical state of the matter in
> the machine's memory determines the output, Seth Lloyd of MIT thinks you
> could run the machine in reverse, feed in information and change the state
> of the memory, the result would be a quantum mechanical micromanipulator.

But it might be a rather limited micromanipulator, since most likely the
state will be stored as electron spins or atomic excitations, not
anything like molecular structures. Still, it might form an useful
interface to nanotech.

> I find all this very exciting, it must have been like this in the late 1930's
> when reports trickled in about nuclear fission and the idea occurred to
> people that a bizarre device like a nuclear bomb might actually be able to
> exist in the real world.

And in neuroscience, more and more people are beginning to think that
neural interfaces are a possibility... Happy new year!

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Anders Sandberg Towards Ascension!
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