From:	"Ojaste,James [NCR]" <James.Ojaste@**.GC.CA>
Subject:	Re: Real-Life Computing ...(OT, obviously)
Date:	Wed, 27 May 1998 14:59:12 -0400

Erik Jameson wrote:
>>There's a whole new angle developing in computing technology though -
>>Quantum Computers. They've actually successfully solved a problem
>>using a device exploiting quantum theory stuff. It's mostly over
>>my head, but the example used involved 4 "operations" to be performed
>>to make a decision. ie: a comparison. The quantum computer
>>solved all four possiblities at once... This is technology that
>>probably won't see the light of day though until....2050? :)
>
>Okay. Can someone, in relatively brief terms, explain what this is? Don't
>get too technical, don't go too long. But this is something that has
>piqued my interest, so I'd love it if someone could offer an explanation
>suited for the layman who has a bit of knowledge about quantum mechanics.

Really basic version:
By using radio signals to twiddle atoms and reading off results using
NMR (getting around uncertainty by doing the same thing to several
"units" and reading only one of them), some researchers managed to
create a 2-bit xor gate out of chloroform. They think that the max
is about 10-11 bits, and they don't seem to have much real knowledge
of actual computers (quoting O(n) for a simple database search, etc).

More complex version:
Basically, each of the atoms used has a spin (they added a neutron
to the C in the chloroform to get it spinning). By exploiting the
difference in spin, they can "set" the hydrogen's initial condition,
flip the whole thing 90 degrees, wait a bit, flip it back. Then they
read off the orientation of the carbon. If the H is spinning one way,
the C returns to its original position. If the H is spinning the other,
the C flips over.

Actual version:
If you're interested in more depth, check out the June Scientific
American, page 66-71.

James Ojaste