X-Message-Number: 12327
From: "John Clark" <>
Subject: Quantum Computers
Date: Wed, 25 Aug 1999 13:03:26 -0400

In message #12304, Thomas Donaldson wrote:

    >nanotech computers and quantum computers are two quite
    >different animals and should not be equated.

"George Smith" < in #12317

    >If being able to "fix" the spin on an atom such that it can then
    >be used to digitize information (per Heisenberg's Uncertainty Principle)
    >isn't a "quantum computer" and if working at the molecular level isn't
    >"molecular nanotechnology" (per E. Drexler), I give up!

Don't give up, but Thomas is quite correct. In a nanotech computer the basic
design and the logic of operation might not be much different than in
the machines we have today, they'd just be a lot smaller and faster.
The individual components of the machine might make use of quantum effects
and you might only need one atom to store one bit of information, but at a
higher level the logical flow of information and the programming would be just

as it is now. That's not the case with a quantum computer, it's far more exotic.

When a conventional 64 bit computer, even a 64 bit nanotech computer,

performs an operation it does it on one 64 bit number, when a 64 bit (called 
quantum computer performs an operation it does it on all 64 bit numbers, all
2^64 of them, more than a billion billion.  Nobody has made a quantum computer
yet and unlike a nanotech computer it's not even certain that it's possible,
some still think it would violate the laws of physics, but the idea is making
converts and each day it looks more likely. I think the tide is turning.

I can't really blame the skeptics, the idea is certainly crazy but it's possibly
enough to be true; you'd sure have to throw away all your programming
books and forget a lot of conventional logic.

  John K Clark     

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