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Light-Based Computers Using Quantum Principles
Maddog2030 cites a story at Science Daily, writing: "Here's an interesting twist to all the news on quantum computing. A computer running similarly to a quantum based computer, except it runs on light at similar speeds for particular tasks. It also rids itself of the many complications introduced by quantum computing."
This sounds more like holographic computing, rather than quantum computing. In QC, a search would involve manipulating the system until one state is left. In this article's example, you still have to iterate over the frequencies to find the frequency that changed. As I am given to understand QC, were this a true analog to QC you'd simple have one color standing alone, with no searching.
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Another example is finding the bounding convex polygon for a set of n points. I don't remember the runtime for the algorithm, but for the real world it's O(n): you get a board, nail in the n points, then find a rubber band and wrapp it around the nails.
The article describes another one of these problems that is solved faster with a physical process, in this case looking up a record in a database. By physically encoding data differently, you can find a record in a large set in a single step (well, maybe not since you still have to FFT the light to find the frequency, so I'm still not sure how this is faster than the O(log n) of an index, remember FFT is also O(log n) where n is the number of frequencies, and you need the number of frequencies to be the same as the number of records so it seems equivelent to me, but there may be some other way of determining the frequency of the altered light).
This can't be used to crack RSA, and it's not a general method of algorithmically running through a large number of possiblilities concurrently, which we get with quantum computers. There may be a way to crack RSA generically with a physical process (didn't Shamir come up with an optical process for 512 bit RSA). But this has nothing to do with that.
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That article was insipid to the point where I couldn't finish it. A few points in the first few paragraphs are worth mentioning:
1) Quantum speeds? WTF is that? There's no such unit, not even associated with quantum computing.
2) The device "mimics quantum interference". No, it's light; it displays quantum interference. Light is photons, quantum particles. Dur.
3) "performs some tasks a billion times faster". This is what I call a 'crazy number' since it's not based on any sort of measurement and thrown in only for show-value.
Don't get me wrong, I'm active in QC research and I like what the folks at Rochester are doing, so, too, the folks in an optics group at Los Alamos. But whoever wrote that Science Daily article is whacked out. It cheapens everything.
Disclaimer/shameless plug: I've recently compiled a semi-technical paper on some of the theory behind quantum computing, as a project in our undergraduate physics course.
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Yes but quantum computing Sounds So Much Cooler....
In all seriousness, this is the sort of situation where the Internet is more a hinderence than a help. Over time discussions such as this will polarize the lay community either for or against a particular area of research, wher two areas of research strive to achieve similar goals.
Public Opinion greatly influences funding of research, so I hope that premature dabates of which technology is superior, won't shape decisions to fund one or the other, since ther is the possibility that one or the other area of research might hit a brick wall at some time in the future, at which point it wll be nessecery to pursue the other area of study. It would be bennefitial to all to have continued both areas of research in parrelel.
Don't get me wrong. I don't believe that discussions like this alone will influence the course of research, but merely that the colaborative enviroment the Internet offers will promote (suprisingly) colaboration to the point where only one research path will be pursued by both teams, working together, rather than competing, as it were.This is an area whewre competition is a positive thing in academic research. I merely question the degree to which the Internet actually contributes to this.
--CTH
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*smirks*
Let's look at the story for a second here folks.
The scientist set up a data-storage device (in this case an acoustically massaged medium), then an information retrieval was carried out against the medium. This retrieval was carried out in parallel. Now this is fairly exciting news, but it has some serious distance to go before it manages to become something general enough to threaten the intellectual-share of true quantum-entaglement computing schemes.
The promises for the device so far seem to be in determining data returns along mulitple paths. In effect, the thing is performing the many many calculations (in this case actually only data-retrievals). However, it's performing them in parallel.
In addition, I'm curious as to how the data is retrieved. If the recombinant beam must be compared to the original beam along all the frequency divisions, there's another indivisible operation requiring some length of time.
But....
It is an interesting method of encoding/decoding data from a medium to a laser without transducers. I'd say that this technology has great promise as a method to be derived from to create all-optical switching fabrics that are actually data-sensitive (how'd you love it if you could decode, process, and filter packet data from the very laser transmission that carried it down the fat fiber pipe...?)
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sn; at god ba g
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