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Science

New Advance In Quantum Dot Technology 80

Posted by timothy from the think-small dept.
sacremon writes: "An article in EETimes describes research at the University of Nebraska on the development of an improved method for the generation of quantum dots. The researchers invoke the infamous 'five years away from having a small-scale quantum computer in the lab,' but the technique looks promising, particularly for generating a large array of quantum dots."
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New Advance In Quantum Dot Technology More

New Advance In Quantum Dot Technology

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  • So, I've become a kharma whore, I guess. Or, you could look at it like this... 3 different ideas, 3 different posts. Since there isn't a good way to comment on part of a post without forcing the reader to parse the whole thing, figure out what's referenced, etc... I figured I'd do what I'd like... and break it up.

    Personally, I'd like to be able to do something like annotation, or the like, to mark up someone's comments, so there isn't the continually need to re-parse things.

    I'd also like to be able to note in my link somewhat automatically that I agree or disagree with the author (a color code)?

    Those are some of my thoughts, all put into once nice package.... if you prefer it that way.

  • Oooh.... let's think of something new, post it to slashdot, and wait and see how long it takes someone to say oohhh... i wish i could have a beowolf cluster of those....
  • It doesn't make much of a difference how small/fast you make the processor if you can't push the data at it fast enough. So far, there isn't even much theory-ware that can keep up with the speeds of processing this is hinting about.

  • Re:Collapse of Civilization? (Score:4)

    by e7 ( 117450 ) on Monday December 04, 2000 @07:56PM (#581805) Homepage Journal
    Quantum money? Is that like, the more accurately you know how fast you're spending it, the less accurately you can know how much you have left?
  • I'll give Craig Bohl one more year to put a decent defense on the field. They need linebackers and defensive backs... now!

    NU should do better next year with a nice crop of fast I-Backs. No more of this big, slow, powerful, can't-get-to-the-outside crap.

    Jesus, they lost to Kanas State. Yes, Kansas State. How embarassing. KSU, the worst team of all time. But the KSU fans are so stupid, they tore down the goalposts like they've never won a game before.
  • These guys are not full of shit! The people working on this stuff are way ahead of their time (20 years or so). This is stuff that can be the future if no other things are invented. It doesn't necessarily have to be the future but right now it is what we believe will be the future. Bandy is one of the smartest men I know and his work with Ianno and the other professors is pretty amazing. This research is not bullshit, this is legit and these guys are some of the best in the field.
  • It's called a "running joke".
  • "He can make is spontaneously appear where he wants. I know him and Bandy is not shitting you."

    Cool! If they can put a quantom dot on the spot (no pun intended)... then I do indeed congratulate them. It would be a good way to start building things like gates, and my favorite...RAM. If they can get them to be low noise, and stable, imagine having RAM cells without capacitors... the size could go way down. If they can make them non-volitle (sp?) (as a quantum dot should be able to be)... then that's even better! (I hope I'm not hyping things too much)

    Like I said later... (#3)... focus on the positive. (I hope they weren't the victims of a bad reporter looking for hype).

    --Mike--

  • Yes, Bandy is a genius... although when he rattled off some equations in his principles of semiconductors class us up and coming geniuses would've liked more than just "and it's obvious" for an explanation. There is more to UNL than football, thank god.

    Mike
  • That's pretty funny. Someone mod him up.
  • Is a large array of quantum dots like a small array of normal sized dots, only fiddlier?
  • You might check out this article: http://xxx.lanl.gov/pdf/quant-ph/9910032 [lanl.gov]

    Is looks to me like this guy Supriyo Bandyopadhyay really is doing some good work.

  • I'm a computer science guy, and I'm interested in quantum computers. I'd really like it, though, if people stopped talking about dots and collapsing waves and gives me an example of the O(n) time for an algorithm on an electric computer vs a quantum computer. The lower bound for a sort on an electric computer is O(n log n). What's it on a quantum computer? O(1)? O(log n)? O(n)? Or am I looking at things in the wrong way?

  • http://xxx.lanl.gov/pdf/quant-ph/9910032 [lanl.gov] is a link posted by user freeinformation. This is a redirect to a 19 page PDF file by Dr. Bandyopadhyay.
  • I just saw the "Quantum Dot Technology" and thought oh god not another stupid sun commercial about the great 'dot'.

  • Total Bullshit! - Count #2 (No interconnects) (Score:3)

    by ka9dgx ( 72702 ) on Monday December 04, 2000 @07:24PM (#581817) Homepage Journal
    "The patent covers an inexpensive construction method for vast arrays of quantum dots, involving an easy-to-perform electrochemical process on an aluminum substrate. Quantum dots are described as "spontaneously" forming atop the aluminum substrate in a regular array suitable for processing information. "

    So what we really have here is a process that just "spontaneously" happens to make a pattern that looks good for storing bits. This is not a process for putting a quantum dot at location X. Stand alone quantum dots certainly have their uses, such as laser diodes, but if there are no interconnects, it's not going to be a computing device.

    In order for this to be useful, you have to be able to put a quantum dot where you want it, and be able to get data into and out of it. You also have to be able to do this and to get at least 1% yield for the entire die, in production quantities. This is not the ballpark this research is headed for.

  • Slashdot Poll Idea (Score:4)

    by Glowing Fish ( 155236 ) on Monday December 04, 2000 @10:06PM (#581818) Homepage

    what do you believe you will actually use in the next five years:

    • A quantum computer
    • a flexible CD
    • a one handed keyboard
    • Mouse marrows to grow brain cells
    • Any of Jon Katz's visionary political or social ideas
    • legos to build a 40 foot tall replication deathstar
    • A stable version of Windows

    Okay, that last one was a little too farfetched... but I do declare Slashdot, you have the vapors!

  • This will make an awsome mp3 player (Score:1)

    by Anonymous Coward
    Imagine a RIO Quantum, storing every song made in existance over time, plus also every dvd , plus every Ebook.

    Mmm, I can just see the HK pirates planning.
  • these dots can be very powerful indeed.

    tcd004 Tired of Election Coverage? How about some Uncoverage? [lostbrain.com]

  • I've also noticed that the flow here seems to be:
    • Story Posted
    • 1st post seekers
    • People who didn't read the story trying to get karma
    • Wouldn't it be nice to have a Beowolf cluster of these?
    • Some intelligent discussion, usually in long threads that weren't first, and therefor never get read because a new story has happened

    I figured I'd try to get at least one of my points into play before the party moved on.

    I really like Slashdot, but I think it can be even better... not quite sure how... but I know it can.

    --Mike--

  • Well, assuming quantum data transmission gets anywhere, the opposite will occur. All transmissions will be totally secure. Quantum data transmission would prevent sniffing. It relies on the Hesenberg Uncertanity principle which states we can't observe certain quantum phenomena without changing them. Thus all packet-sniffers and the like would be detected instantly - the message on the other end would be garbled.

    So if I encrypt my session key and send it along a quantum channel (encrypted with RSA) it's true that someone can intercept the message and easily decrypt the session key with a quantum computer. But the recipient will know that something's up, and I will never send the actual data.

    That's a whole different problem.
  • void breakdown(int somenumber){
    while(!done){
    /* find factors of somenumber */
    /* check to see if both numbers are prime */
    /* repeat until halfway to number */
    }
    }

    Considering a quantum machine can do a huge number of these checks at one time, breaking down a large number into its two prime constituents is trivial.

  • It wont affect steganography, or one-time pad based encryption.
    It may make a mess of public key encryption though. You`d need to secretly communicate to your correspondants the page/offset/password you are using for the publicly posted message you are sending. If you could do that then you may as well send the message secretly anyway!
  • I think this troll has a good point. At least the word "might" should be in there somewhere.
  • I doubt that it would be released by the NSA... why should they? If the NSA does have quantum computers, they definitely wouldn't tell anyone. Just think of what enemy nations would say: "Oh, they can crack any cipher in current use. I guess we just won't send any secret information for a while", and the NSA doesn't get any information.

    Probably more likely is that it's starting to be re-discovered by the public (assuming that the NSA has QCs), just like RSA. If so, we probably won't be hearing anything about it from the NSA for a while.


    -----

  • Well, I assumed we were looking at the word "instruction" in a new light. Algorithms are lists of instructions. Under a quantum computer, we might have new instructions, such as "pick highest from list" which would be O(n) on an unsorted list in a non-quantum computer, but might be O(1) (doable in one step) on a quantum computer. That's what I'm getting at, I guess.

  • Well now if they can just develop some quantum dashes, they can build a quantum telegraph!

    Quantum morse code...ahhh... It could revolutionize the railroad industry!

  • Quantum Comps replacing binary computers (Score:3)

    by the_alkaloid_w_kick ( 258584 ) on Monday December 04, 2000 @08:56PM (#581829)
    Don't quite throw out that "old" binary computer yet - there are certain data types that fit quantum computers, and others that don't. Since QCs work differently, binaries still kick butt in certain areas. If you really want the skinny, try this url - http://www.newscientist.com/nsplus/insight/quantum /genious.html. It's very idiot-friendly (I've seen some of these fp's).
    Another bit - I was reading the NSA website today, and noticing that they state something about "strategically limiting certain key technologies" in the interests of nat'l security. I have also noticed a lot of recent quantum related breakthroughs (quantum decoherence-free states, quantum cryptography, and easy methods of making entangled states). Not to be paranoid, but could this be a NSA release of technology? Who knows? :) Just a random thought. Must be getting tired.

    Matt

  • How it all works... (Score:4)

    by intmainvoid ( 109559 ) on Monday December 04, 2000 @07:00PM (#581830)
    Information about how quantum computers work, from a competing team also hoping to build a quantum computer, is here [unsw.edu.au],

  • Re:Collapse of Civilization? (Score:3)

    by GMontag451 ( 230904 ) on Monday December 04, 2000 @08:57PM (#581831) Homepage
    Simple...
    while (!confessed) {
    beat prime number over the head
    tell prime number its partner already confessed
    offer prime number a shorter sentence if it
    confesses
    // add other techniques here as you see fit
    }
  • I think Quantum technology will take the biggest step when big scientific computer will get a "boost module", where Quantum calculations could be programmed to do quantum work, as factorisation. As long as the new techlogy will be kept in labs (or at the NSA), the real power of quantum will not give us any power. I suspect first companies like IBM that could loan some quantum cpu time for a lot of companies, for some governement agencies that could not afford one.

  • Imagine the possibilities! (Score:3)

    by quantax ( 12175 ) on Monday December 04, 2000 @07:01PM (#581833) Homepage
    This has all probably been said before:

    1. Distributed.net: Crack the encryption before you can actually hit the key

    2. 3D: Real time rendering in the palm of your hand.

    The power of this technology is friggen sick. I hope we put it to a good use, like porn hosting... You can never get enough porn. No such thing as too much porn. Usually.
  • I stand by my word. But this algorithm you link to cannot factor a prime number. Nobody can factor a prime number. I posted that because the original poster referred to factoring a prime number and I was just making the point that RSA actually uses composite numbers that are a multiple of two large prime numbers. And the only way you can factor a prime N is N*1, but this doesn't count.

  • well (Score:1)

    by deft ( 253558 )
    that 7up guy may come back then.
  • isn't that the new kind of ice cream being marketed as "the ice cream of the future"? maybe i'm thinking of something else...

    -----
    # cd /
  • Researches in Silicon Valley today announced that, within five years, they would be able to produce any number of quantum dot-coms in a small laboratory, at little or no cost. "This redefines the nature of cool," say John Q. Hoper, director of product developement at XOREX, "solving the urgent need for new, turnkey business solutions developed at the quantum pace."
  • Sadly, I think the lego idea is the most feasable ;(
  • Quantum dots is just the first step in making a quantum computer, which is why the 20 years till desktop line in the article. What is demonstrated is far more modest than the press release SEEMS to say. What was demonstrated is the ability to massively manufacture quantum dots. The next step would be some kind of mask like technology to control exact patterns of the quantum dots. It seems that should be possible since their process require very fine control, a mask should be enough to selectively prevent the growth of quantum dots in places. The next step would to build a quasi-quantum computer, that is a computer whose operation is stilled based on classical information theory, but the physical principals is entirely quantum. Such computer would still be vastly supperior to current computeres in term of power consumption and speed, that is because computers based on quantum dots does NOT need interconnects, because everything is through field effect. The state of a quantum dot affects the one next to it in similar way a atom affect atoms near it. In fact quantum dots often being called artificial atoms because the quantum mechanics of an electron inside a quantum dot is so similar to that of a atom's electrons that they are pratically identical. Only after the quasi-quantum computer is bulit are we likely to be able to deal with the next challenge (unless some surprise discovery/invention changes things) which is coherrance. Quantum computers right now are extremely fragile. After you put the device in a superpositioned state, it doesn't take much to destroy it and have it decay into classical states. However from what I hear the most robust superposition state was achieved in a quatum dot which do raise the hopes. I hope the best luck to these researchers but I am weary of the fact that they patented the process which pretty much prevents others with shallow pockets from perfecting their technique, and slowing down the process of innovation. Hopefully their licensing agreements are generous.
  • Ok... here's the beef.... "You could build a quantum computer that has 2 to the 1,000th bits of data, which you could never do with a binary computer, because the number 21,000 is larger than the number of atoms in the known universe. But a quantum computer could store that many bits with just 1,000 atoms," said Bandyopadhyay.

    Bullshit! Every time you add a bit of information to a quantum state, you double the number of possible states available, at the cost of doubling the time it takes to determine the state. I don't know about you, but I don't want to wait around for the lifetime of 2^100+ universes just to save a few bits of memory. If anyone gives me grief, I'll be happy to do the math, and show just how absurd the hype is.

  • > "...but the technique looks promising, particularly for generating a large array of quantum dots."

    That's what we really needed - after what Sun did, a large array of quantum dot-com s :)

    --

  • "fp" creativity (Score:1)

    by Anonymous Coward
    the lack of "first post" [slashdot.org] creativity has been bothering me lately. Why, when getting the first post, do slashdotters just settle for the standard:

    subject=fp

    body=fp

    quite honestly, it's getting boring. In the time it takes you to constantly reload the slashdot page waiting for a new story to be posted, you could be looking around the internet for something more creative to post. I'm bored, so when browsing at -1 I'm looking for the funny, creative troll. Is anyone else bothered by this, or is it just me?

  • This article in eetimes.com is terrible.

    Just the type you see in newspapers and magazines all the time: Presenting some major "500%" advance in some area or the other and the corresponding scientists being "20 years ahead of their time". Now I don't say this is all made up, but being a scientist myself I am not ready to believe anything without further proof.

    So I am asking: Where can you find more information on the work described in this newspaper article? Have the scientists published their results in one of the well-known journals like PhysRev, APL, etc.?

    The second weak point about this article is that the author is mixing different applications of quantum dots without distinguishing them in any way. At least three properties of quantum dots can be made use of - and they are very different:
    1) Optical --> Lasers and Detectors
    2) Electrical --> Single-electron devices
    3) Quantum --> Quantum computers
    And each of these properties needs special tweaking for the desired application. It's not like you can produce the perfect quantum dot sample that can be used any application.

    So I am asking: What properties are the named scientist actually working on?

    My final summary: Unfortunately this article is not presenting anything of value as different aspects are freely intermixed and no clear information is given. Very sad - quantum dots/cryptography is actually an interesting subject.

    knutbert
  • Well, that might be a bit extreme, but wouldn't this render most encryption obselete overnight? This would mean that bank records, cell phone calls, e-business, and who knows what else will be comprimised. I've heard a bit here about "quantum cryptography" but does anyone have any links to info about it?
  • When I first read the headline, I thought I saw "New Advance In Quantum Dot Com Technology." And I was remarkably confused when I read the caption thereafter.
  • I will give you $100 billion if you post an algorithm to "breakdown a prime number" below:
  • > I just saw the "Quantum Dot Technology" and thought oh god not another stupid Sun
    > commercial about the great 'dot'.

    Nope - nothing "great" but "quantum" :) - still rather close to the reality :) Quantum Dot-Coms :) Same size, eating same amount of money :) do you sense a pattern here? :)

    --

  • This guy's got the right idea. Why put all your good ideas in one post, when you can distribute them among *three* posts so as to maximize karma harvest? Brilliant!

    [Want to read more about why I think this is a good idea? See my next post]

  • What is the point of falsely claiming a goatse.cx link?
    It's not funny, fools no moderators, and is trivially tested.

    I just don't get it. Shouldn't there at least be some small bit of cleverness involved?

    Pete

  • Aside from the misfortune of having a moron run off with your date, what you did back to him was fuckin beautiful.

    Oh yeah, nano technology. Very, very cool. It sucks that it's going to take 20 years to get commercial versions of the things that are discovered today.
  • Yeah, we all miss McBride but what does this have to do with quantum mech. Unless somehow we can get 5 linebackers to occupy the same state at the same time (superposition) and bring our defense up to par with... ahh never mind.
  • Spontaneous is not the same as random. He can make is spontaneously appear where he wants. I know him and Bandy is not shitting you. These guys are way ahead of their time and their research is going to bring new ideas to the field.
  • This is real and not bullshit. Bandy, Dillon, Ianno, Snyder, and Williams are extremely bright and are not out to try to pull the wool over peoples eyes. This stuff is real and ahead of it's time. You do the math then run it by Dr. Bandyopadhyay and he'll show you the truth. Don't go trolling without the in depth knowledge of the papers they present. It says in the article (done by somebody that might not be as knowledgable) that it is "far from perfect". But don't question the knowledge of the people working on it.
  • I am a graduate student studying quantum dot formation for my doctoral thesis. As someone else pointed out, the current application of quantum dot self-assembly is for devices like lasers and photodetectors, not quantum computation. So, development of high quality "quantum dots" should not be confused with the practical production of "quantum computers". Still, I think the ability to engineer these structures is a great step in that direction.

    For anyone who's interested in the physics of quantum dot self-assembly, I've posted some papers and presentations on my website [umich.edu]. My recent research proposal [umich.edu] deals with a physical simulation of quantum dot growth. I try to write without jargon, so they should be understandable to anyone with a science or engineering background.

    Rick Wagner
    Department of Chemical Engineering
    University of Michigan

  • This article is pretty bad. I was working on this stuff in graduate school nearly two years ago. The info about special current gradients and voltages over time are well known and reasonably well explored.

    The patent covers an inexpensive construction method for vast arrays of quantum dots, involving an easy-to-perform electrochemical process on an aluminum substrate. Quantum dots are described as "spontaneously" forming atop the aluminum substrate in a regular array suitable for processing information.

    Yes, the electrochemical process is easy. Industry has been doing it for many years -- it's called anodization. Make the aluminum substrate an anode, pass current through it and some sulphuric acid, and you have your quantum dots. Nothing spontaneous there. And they are not formed atop the substrate, but within. Also, the quantum dots are periodically spaced.

    This is excellent technology. The application I was working on was ultra-high resolution display technology.

    Too bad they are going to tie all of this up with a patent. Maybe some publications can prove prior art!
  • ARRGGGHH!!!

    Someone explain this to me! I'm reading this article and it goes into detecting bombs that are supersensitive. It goes like this:

    Someone tells you there's a bomb in the room that goes off if a photon hits it. You can't detect it using normal means because you'll set it off.

    Enter Quantum Mechanics! You have a room with two mirrors that are perfect. A photon will just bounce back and forth forever. Stick a near-perfect mirror in the middle of the room. Now a photon has a %.000001 chance of going through to the other side every time it hits the mirror. I'm fine with the quantum theory up until here.

    Now they say that because of the uncertainity principle, you won't know if a photon has gone through to the other side until you actualy measure the photon and see if its gone over! The article states that if you have still have a photon on the left side, then there must be a bomb in the right side. WTF?!?!

    Just because you don't measure the photon doesn't mean it's not doing anything!! My question is, why is it not possible that the photon went over to the other side and set off the bomb while you were waiting?????? Just because I didn't measure the photon, doesn't mean it didn't bounce over!!!

    Are they saying that the photon doesn't do anything UNTIL I measure it? Then it determines which path it's going to take??? If they want me to accept it on faith, I can do that. But I just cannot see that happenening!!! So in effect, I'm going back in time measuring this photon!!

    They're actually making computers based on this shit?!?!?!!

    Trains stop at a train station. Buses stop at a bus station.

  • ...that they are still working on Quantum Yakko and Wakko technology.

    ---

  • Theory. (Score:3)

    by Matt2000 ( 29624 ) on Tuesday December 05, 2000 @06:45AM (#581858) Homepage

    I've been reading with interest for some time now the developments in Quantum computing, and it seems that researchers are now faced more with engineering problems rather than theoretical ones. No one is really questioning the computing abilities of quantum devices in theory, we're just waiting to see how they could be built.

    My problem is then with the field of computer science in general and why there isn't much computational theory being done with quantum devices in mind. Coming from a comp. sci. theoretical backgground most of the heads in the field are either ignoring quantum computing or scoffing at it, while keeping their heads stuck in the P=NP sand and hoping it will all go away.

    Does anyone out there have any info, preferrably links, to theoretical work going on with regard to quantum devices?

  • Will start-ups taking advantage of this new technology be known henceforth as `quantum dot coms'?

    <ducks>

  • Simple... Set up an array of pixels of arbitrary resolution, then program the quantum computer to search through all combinations of pixels to produce say 2^16 of the best porn pictures possible. Because quantum computers calculate all possibilities simultaneously, you'd have your porn in a femtosecond. And it would literally be the best porn that could possibly ever be made, because the computer went through every possible solution!!

    The actual possibilities of a decent quantum computer are so vast, that people either have no way to comprehend them yet, or comprehend enough to be frightened by the power.

    Imagine programming a quantum computer to search through every possible combination of a large array of atoms, so that you would have a transwarp engine. Basically, you can set up whatever paramaters you want, and the quantum computer will find for you what you want, or tell you that it doesn't exist.

    The examples I used are a bit off, as how do you define for a computer what good porn is? But if you somehow connected an arousal-sensor to the human brain, it could be trivial... Quantum computers will basically answer any question you ask, as long as you ask it properly, and the computer has enough qbits. Near infinite amounts of brute-force computing power is nothing to sneeze at.

    Ask and ye shall recieve... scary eh?

  • Quantumdot.org [networksolutions.com]: News for nodes. Size matters.
  • i'm still of the belief that we should master our regular computer technology before to moving on to quantum computing-- give ourselves 2 good legs to stand on. but maybe i'm just stuck in the vacuum tube age.
  • Yes, the decoherence time may be awful if you are using exitonic states or if you are trying to use the orbital states of the electrons, but it may (hedge) not be true for the spin degree of freedom for the electrons.

    dabacon
  • A stable version of windows will come before anything Katz has predicted.

    -Chris
    ...More Powerful than Otto Preminger...
  • I think you totally don't get it. It can do a factorisation of a number 2 exp 1000 in one step (or near), simply by testing all the 2 exp 1000 possibilities simultaneously and get the answer right back. Just get it and eat it!
  • i agree. i do feel proud that my univ. is featured on slashdot

  • WOW! (Score:4)

    by cluening ( 6626 ) on Monday December 04, 2000 @07:15PM (#581867) Homepage
    The University of Nebraska really does do research, and interesting stuff at that! All this time I have been going here I thought we were just a front for the football team...

    I guess I can feel proud now. :)
  • I once had a polka-dot bowtie, but being horrendously out of fasion, I burned it and laughed hysterically. Sadly, it never was very good at computing anything. And think of all the dots it had. Such a waste.

    I'm much fonder of Steve Howe's Quantum Guitar... its at least useful, in an asthetic way.

  • Oh lala.... Hard to eat technology, isn't?

  • No quantum computers from this design (Score:3)

    by KIngo ( 168933 ) on Monday December 04, 2000 @11:11PM (#581870)
    I've been working quite a lot on semiconductor quantum dots and let me tell you: Nobody's ever going to make a quantum computer from self-assembled quantum dots. There's a whole lot of reasons why this is highly likely but the primary problem is: you cannot easily address them. There is currently no other way to read and write a quantum dot but by placing a SNOM (scanning near field optical microscope) right above it. And SNOM tips are still far to large to really select a single quantum dot. And by the way, after a few milliseconds, the excited state usually recombines due to decoherence, so you would need to constantly refresh all quantum dots every few milliseconds by a very elaborate mechanical process. Finally, with so much decoherence, it's not really a quantum computer anymore, but just a very expensive memory chip.

    There are promising designs of quantum computers, but they are not based on a semiconductor design. My personal opinion is that quantum computers will be first be realized in ultra-cold systems such as linear ion-chains. Any design that does not include the concept of a data bus is IMHO worthless.

    To conclude, self-assembled quantum dots as described in the article do have their place: in optical devices such as semiconductor lasers, infrared sensors and highly specialized ultra-accurate gauge devices.

    Just my 2 nm ...

  • t the cost of doubling the time it takes to determine the state

    In most cases you can't determine the quantum state - you measure it. And the measurement time does not double whenever you add another qubit. I'm sure you could do the math, not so sure if it would be the right problem
  • My favorites are "it is intuitively obvious", and "left as an excercise to the student/reader".
  • Cool! If they can put a quantom dot on the spot (no pun intended)... then I do indeed congratulate them. It would be a good way to start building things like gates, and my favorite...RAM. If they can get them to be low noise, and stable, imagine having RAM cells without capacitors... the size could go way down. If they can make them non-volitle (sp?) (as a quantum dot should be able to be)... then that's even better! (I hope I'm not hyping things too much)

    Sorry, but you are. I'm actually a grad student working on the theory of these things at UC Berkeley. Coherent quantum states(so that you can do useful things with them) are very fragile and make "volatile" RAM look like a stone tablet. And, even with quantum dot arrays, it's not exactly clear how we should use them to build a QC architecture (see papers by Vincenzo, etc., including a recent one in Nature). And even if you agree to use one of these architectures, how do you manipulate and measure the states? EPR machines are big, and so are lasers for doing optical faraday rotation measurements...saying that it's not quite at the point where you could toss it into a PCI slot is putting it mildly.

    That being said, it's exciting, and quantum dots are probably the best bet we have for making a scalable QC (sorry NMR guys). And in five years, who knows? If we had a quantum computing Manhattan Project, it could happen....

    --js

  • I still don't get it. Roughly speaking Isn't any computation that requires a guess and validation from 2^n possibilibities NP-Complete ?

    I can see how N qbits can "represent" 2^N possibilities. What I can't see is how one reads off the correct result :)

    From my limited "getting it" QC is good for geometrically increasing N problems n^3, n^4, but it doesn't solve NP-completeness.

    I also know there is something I don't understand in Quantum Entanglement, but I don't think this is a help.

    perhaps someone can confirm or disabuse my understanding

    Winton
  • these guys sure seem bent on contributing to military technology. great. just great guys. anything to keep the funding rolling in. To be fair, my impression is based on the article, not the actual research
  • 2. 3D: Real time rendering in the palm of your hand.

    I want the Playstation 9!!!
  • I vote brain cells! Oh wait..it's supposed to be what's likely! Oh. Uhhm, in that case, probably the lego thing, or *maybe* the keyboard, but I doubt it. The flex CD isn't gonna happen and the quantum computer isn't something you'd really want to use for day-to-day computing even if it did work like it was supposed to:
    Programmer1: Hey, how come I can't get this pseudo-random number generator to generate the same numbers it did before?
    Programmer2: Oh that's 'cause you're usin' a `Quantum Computer'. See it uses the principle of quantum indeterminancy to generate, not *pseudo* random numbers, but actual random numbers.
    Programmer1: So I can't make it recreate the same sequence of numbers it did last time?
    Programmer2: No. Also, the computer is capable of generating non-deterministic behavor.
    Programmer1: What kind of behavior?
    Programmer2: Well, just last week, it grew a mouth and ate a programmer who hit it's keyboard too hard.
    Programmer1: I think there's a Dell over there with my name on it. That `bleeding edge' technology stuff is getting a little too weird for me...
  • Seriously...Leave me alone.

  • Re:Collapse of Civilization? (Score:3)

    by Fervent ( 178271 ) on Monday December 04, 2000 @07:18PM (#581879)
    The Code Book [amazon.com] has a great section about quantum cryptography for "normal people". It helps to get the basics down (like quantum money and breakdown of prime numbers using quantum computing) before tackling the more complicated things like actually creating a quantum encryption scheme. Highly recommended.
  • and commercial versions won't be available for at least 20 years I can't wait till the day when these comps come out, it will be nice to have to pay immense amounts for a computing system. Crap, wheres my wallet?
  • It's worse than that, you can build your state with 2^1000 bits of data, you can perform 2^1000 simulataneous calculations, but in the end you get one 1000 bit number and then you have to start again.

    Most of the piece is oversimplified hype (more correctly known as bullshit).

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