[extropy-chat] diffraction limit

[Brent Neal]

 (5/31/04 15:34) Dan Clemmensen <dgc at cox.net> wrote:

>I don't know much about spintronics, but in one aspect it appears to 
>enable quantum computing. In another aspect is appears to permit each 
>electron in a flow to carry a bit.   My gut feeling is that electron 
>spin is even more uncertain (in the Heisenberg sense) than electron 
>position, but I'm willing to be educated on this. If my intuition is 
>correct, spintronics will cannot be scaled smaller than electronics., 
>because electron spins will merge when the electrons get too close to 
>each other. If this is correct, electronics will win, because it is 
>easier to simply keep improving electronics than it is to shift to 
>spintronics.

That's what I think as well, however, as I understand it, the energy (and thus time) it takes to change the state of a spin-based device is less, which is one of the nice things that people are interested in.



>
>Quantum computing (with or without spintronics) allows for fast parallel 
>processing for a certain class of algorithms. AFAIK it is not a general 
>substitute for binary computation. This means that it cannot substitute 
>for electronics in most cases, and that a large new software 
>infrastructure will be required. Contrary to popular belief, software 
>design effort generally overwhelms hardware design effort at  the system 
>level. I doubt that quantum computing will have much impact except in 
>specialty areas before we reach the CMOS density limit.

When people ask me about quantum computing and what it means, I usually say that it makes hard computing problems easy and easy computing problems hard. That's a gross generalization, but its pretty accurate. QC in and of itself is not really useful. Combining QC with traditional computation is interesting. But, its all moot at the current stage of the game because we cannot quickly and reliably entangle more than 7-8 qubits. I'm a few years out of the loop in QC, though, so its possible that the tech has gotten better. But not -that- much better. :)


B
-- 
Brent Neal
Geek of all Trades
http://brentn.freeshell.org

"Specialization is for insects" -- Robert A. Heinlein