Researchers Develop Quantum Processor

[TechBear_Seattle]

Researchers Develop Quantum Processor

A computer chip based on the esoteric science of quantum mechanics has been created by researchers at the University of Michigan. The chip might well pave the way for a new generation of supercomputers.

Employing the same semiconductor-fabrication techniques used to create common computer chips, the Michigan team was able to trap a single atom within an integrated chip and control it using electrical signals.

As of yet, the technology is not applicable to typical desktop PCs or servers, but quantum computers are said to be promising because they can solve complicated problems using massively parallel computing.

That is accomplished by the quirky nature of quantum mechanics, said Christopher Monroe, a physics professor and the principal investigator and co-author of the paper "Ion Trap in a Semiconductor Chip." He explained that that chips can process multiple inputs at the same time in the same device.

The article continues at http://news.yahoo.com/s/nf/20060113/bs_nf/40876

A very exciting advance, especially if the process can be made commercially viable. On the other hand, I recall reading in Scientific American a few years ago that the potential power of quantum computing would made current data encryption processes obsolete. Something that would take tens of thousands of years to decrypt by brute force using current technology could be done in a few hours using quantum technology. The last paragraph of the article makes me very uneasy.

[htuttle]

1. I originally read your subject line as 'Researchers Develop Quantum Power'

...and I was about to start celebrating ("We're saved!") when I realized what it really said. I suppose ZPMs are still a few years away, then...

Well, maybe these chips will help us figure out that little 'energy problem' we have -- either that, or more likely allow us to play "Grand Theft Auto" in fully immersive VR 3D at twice the speed....

[Occulus]

5. A Deadalus or Pegasus may be closer than you think, though

http://www.newscientist.com/channel/fundamentals/mg18925331.200

:hi:

[HysteryDiagnosis]

2. Sig.... If you make yourself a sheep, you are probably

God... or Darwin, whichever you prefer.... :)

[murray hill farm]

3. It is a wonderful advance.

for medicine alone, it is wonderful...for the whole human race is wonderful.

[phantom power]

4. I have this mental image...

"Behold! Our quantum semiconductor chip!"

"But... it's one bit."

"Imbecile! It's a quantum bit! It can explore two possible states in parallel! One or zero! HaHaHaHa....!"

[Dead_Parrot]

6. Very cool...

...although I'm slightly puzzled by the opening line: So far as I know, all processors are based on quantum mechanics - it's the underlying science behind semiconductor technology...

Ah well. That's pop science writing for you. :)

[TechBear_Seattle]

7. Actually...

All processors, even the "quantum" ones, use ordinary physics. The difference is that the transistor at the heart of current processors has only two, mutually exclusive states: on or off. The transistor analog in a quantum processor can be on or off, but these states are not mutually exclusive; a quantum transistor can be on, off, somewhere in between, all of the above or none of the above.

I've followed the theory of quantum processors in "Scientific American" for many years. My understanding of how it works is that the quantum processing part of the processor chip is a net of quantum transistors. They are put in an indeterminate state and given the initial input. With only small nudges from a traditional processor outside this net, the quantum transistors "collapse" in to what is more or less the correct answer, tremendously faster than a traditional processor could do the same thing by brute calculation. I don't think the transistors actually rely on quantum uncertainty or the collapse of a wave function, just that they behave as if they did.

[phantom power]

8. A quantum computer does truly invoke superposition

and then decoheres. The trick to making a quantum computer perform a task is to set up the "problem" so that when it does finally decohere (collapse), it's state is the solution to the problem you were trying to solve.

[TechBear_Seattle]

9. Glad I got the important part right

I thought that the analog to transistors in quantum processors only simulated quantum behavior. I would really like to see how the behavior is invoked, but I fear I would need a graduate level physics class to understand it.

[phantom power]

10. I don't really know either. It all seems to be variations on...

preventing interactions with surroundings. Most "normal" interactions cause decoherence, which I suppose is the main reason that nobody does this (yet) with more than a few bits at a time, and it takes a lot of special hardware to do it.

There is an interesting discussion of superposition and decoherence here, by one of my favorite authors (I skimmed over most of the inner product math, although I don't think any of it was real intractable, if you are familiar with vector spaces).

http://gregegan.customer.netspace.net.au/SCHILD/Decoherence/DecoherenceNotes.html

He makes the observation that in the biggest picture, decoherence never actually happens. It's what we "see" as a result of having only incomplete information about a system. So, we are all superposed, all the time, along with the rest of the universe, according to the model of quantum mechanics. We don't see it as such, because we cannot access that much state information about the universe.

I suppose this is another way of saying that our knowledge about the detailed state of the universe is very, very incomplete, since we can only observe superposition in very very small systems :-)