20031016, 23:51  #1 
Bemusing Prompter
"Danny"
Dec 2002
California
2^{3}×3^{3}×11 Posts 
quantum particles (and computation)?
This is to anyone with much knowledge in quantum computation. I'm wondering, what makes qubits and classical bits so different? I know that they're largely differentm, but I just don't really know. For example  why do algorithms like Shor's factoring algorithm only work on quantum computers?
Also, is it possible to simulate quantum particles on a classical supercomputer and carry out lowlevel quantum computations? Just wondering. 
20031017, 00:27  #2 
Aug 2002
Ann Arbor, MI
433 Posts 
I wouldn't say I have "much" knowledge, but I have a basic idea. The advantage of qubits over classic bits is that qubits are able to hold multiple states at once. Instead of just being "on" or "off" like classic bits, a qubit can be "on/off", "up/down", and "right/left" at the same time. As far as computing goes, this means one unit of storage (in quantam computing a particle, in classic computing a switch) can hold something like 8 times as much information as in the classical model.
Also, I may be confusing this with how the brain works, but quantam computers should be able to process in parallel. Classic computer's switches need to receive information from a previous switch before acting, so essentially the computer is limited to one string of operation at a time. Quantam computers could theoretically have multiple strings of data working at once. In terms of, let's say factoring, classic computers can only really test one factor at a time, in rapid succesion, where quantam computers could check multiple factors at the same time. Hopefully somebody with a bit more knowledge can step in and solidfy or fix what I've said 
20031017, 01:55  #4 
Jan 2003
North Carolina
2·3·41 Posts 
I found this to be an interesting article: http://www.sciam.com/article.cfm?art...88EEDF&catID=2 and it mentions Shor's algorithm, describes a 7qubit machine and it techonolgy limitation(s) for creating a 100qubit machine. If you search on "quantum computing" you'll find other articles. enojy.

20031017, 07:48  #5 
"Gang aft agley"
Sep 2002
2·1,877 Posts 
I found this page to easier to read than most others and it has nice references:
http://www2.latech.edu/~dgao/CNSM/quantumcomput.html 
20031017, 21:18  #6 
Aug 2002
2^{6}×5 Posts 
Classical bits can only store 1 state, while a qubits can hold a supposition of many, many states at once. Performing a computation on these qubits is like performing a computation on many sets of classical bits at once.

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