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Science Technology

IBM Develops Quantum Computer 180

Posted by michael from the whiz-bang dept.
JSC writes: "IBM has developed a quantum computer consisting of five atoms that work as the processor and memory. It's a nice advance of the state of the art...unfortunately, we won't see them on the shelves for about 20 years." Update: 08/15 06:49 PM by H :Check out the official IBM release - thanks to netMonkey for the update.
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IBM Develops Quantum Computer More

IBM Develops Quantum Computer

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  • Finally something of this development is coming out in a workable format. I heard about this in a Scientific American years ago and it looked very promising.

    Even the samurai
    have teddy bears,
    and even the teddy bears

  • Perhaps IBM along with Ziggy... (Score:4)

    by AntiPasto ( 168263 ) on Tuesday August 15, 2000 @06:11AM (#854641) Journal
    can finally bring Doctor Samuel Becket home with this new quatum leap computer! ;P

    ----

  • I am waiting to see what we are going to get, in terms of cpu's five years from now, with things advancing the way they are....
  • a beowulf cluster of these? :)

    Come on, I deserve karma for posting it on-topic and using my real name :)
  • Man, 20 years? well, I bet we will still be arguing whether it should run Linux on Windows by the time these puppy's hit the market...
  • Can they make it out of Everlasting Gobstoppers instead?

  • Key cracking (Score:3)

    by Mike Schiraldi ( 18296 ) on Tuesday August 15, 2000 @06:12AM (#854646) Homepage Journal
    This will allow the government to crack 5-bit encryption in fractions of a second! Think of the repercussions for privacy! No longer will the NSA have to brute force their way through the entire keyspace (more than 30 possible keys!)
    --
  • Did I read that right? 5 atoms that work as a processor and memory? Geez... I just don't know where I will find room for that on my desk...
  • If people have trouble keeping track of their laptops, I can easily see myself misplacing one of these...


  • At billions of simultaneous calculations (simultaneous means less than one second :) ), that would make a beowulf obsolete I would imagine...

  • 5 Atoms? (Score:5)

    by pigpogm ( 70382 ) <michael@pigpog.com> on Tuesday August 15, 2000 @06:15AM (#854650) Homepage
    5 Atoms? We won't see them on the shelve's at all - unless your eyesight's a lot better than mine...
  • Wow, pocket lint atoms used for computers. An untapped resource?
  • This state would represent both zero and one and everything in between. Instead of solving the problem by adding all the numbers in order, a quantum computer would add all the numbers at the same time.

    Does that mean I'll be able to be everywhere at once? Of course that could work both ways -- being everywhere presents a big target...
  • Will be interesting to see if cryptography can find a way around this...or will this become a technology that only `they` can use?
  • There's much more detailed information from IBM Research [ibm.com] than was included in the press release. It's interesting that apparently Los Alamos has already developed a 7-qubit computer, it's just that they haven't used it to solve a real math problem yet.

    --Chouser

  • Programming Quantum Computers (Score:4)

    by WinDoze ( 52234 ) on Tuesday August 15, 2000 @06:18AM (#854655)
    I wonder what's going to happen to us programmers. I had heard a while ago in Scientific American that programming Quamtum Computers required a radically different approach than those used today. I wonder how much different it will be, and how us "old-timers" will deal with it.

  • ...how clusterable is it? 2000 of them working in parallel...can you say "Exaflop", boys and girls? RC5 might just get cracked pretty damn quick with that thing.
    So when's the PSC [psc.net] getting one?

  • Innovations galore! (Score:3)

    by dbthomas ( 201509 ) on Tuesday August 15, 2000 @06:18AM (#854657)
    Let's hope that by 2020, when quantum computing hits the market, Intel will be close to rolling out the PXIII and promising that within 5 years they will make the jump out of x86 architecture. Of course, I'm probably being impractical...
  • Moore's Law is not an axiom (a law which is accepted without proof). It's more of a rule of thumb.

    Perhaps a quantum processing unit (QPU?) would be more useful as a self-contained accelerator card for a traditional computer.

    Which brings us to something I've always wondered: How does does one (efficientl) program a quantum computer? Wouldn't the time spent configuring the atoms with their billions of values exceed the time saved by the quantum operations?
  • Mass-producing quantum computers would require fabs to completely overhaul the existing equipment that they purchased for the production of Silicon chips. Considering how long it took Intel to merely migrate to hardware that would allow them to produce chips at .18 micron instead of .25 micron, I would not expect existing companies to migrate to the production of quantum computers until well after they have been used as supercomputers for a few years. We may see quantun supercomputers being produced within the next 20 years, but it will probably be far longer before people can purchase them for home use.
  • i'd be more afraid of a criminal who uses it to crack encrypted transmissions containing credit card numbers. of course, by the same token, encryption software cane take advantage of molecular computing to increase the size of its encryption keys. so in the long run this has no effect on encryption.
  • Is it possible that IBM has also developed the world's first Heisenberg compensator?
  • Don't sneeze!

  • Just don't sneeze.

  • Predictions (Score:5)

    by pigpogm ( 70382 ) <michael@pigpog.com> on Tuesday August 15, 2000 @06:21AM (#854664) Homepage
    PigPog's Law: The number of atoms in a quantum computer will double every 18 months.

    PigPig Gates says: We'll never need more than 640 protons.

    PigPog's Uncertainty Principle: We may know where the computer is or which direction it just blew off the table, but never both at the same time.

  • Yeah but... (Score:3)

    by Xentax ( 201517 ) on Tuesday August 15, 2000 @06:22AM (#854665)
    Note that the 3dfx video card is 4 of the 5 atoms, and 2 of the 4 are atomic fans. Otherwise, the whole thing would split from the heat. You thought melting was bad -- imagine your computer going critical and wiping out the city! Dang overclockers....

    Xentax
  • It mentions that quantum computing will be incredibly useful for key-cracking, web-searching etc, but does anyone know what difference this will make to the end-user?

    Also, how are we going to program these baby's? Surely current techniques, languages etc. will all be insufficient?

    Questions, questions.

    Also, while I'm at it, This [qubit.org]is a good place for a quantum computing primer.
  • This is true. The American government are going to pump money into this and reap the rewards by being far ahead of other groups when useful sized quantum machines appear. They could feasibly monitor everything that goes on online. Hopefuly legislation concerning data privacy will have been improved by then. Oh but wait a minute they ultimately control that too.
  • Will Quantum Computers be the smallest computers ever build?
    So after Quantum Computers, Computers would only get bigger and bigger.
    It sounds like a strange idea.
    The distance between insanity and genius is measured only by success.

  • This will allow the government to crack 5-bit encryption in fractions of a second! Think of the repercussions for privacy! No longer will the NSA have to brute force their way through the entire keyspace (more than 30 possible keys!)

    Seriously, though, if this follows the usual track of computer hardware development, sooner than most expect, there will be an operating model. This would enable the NSA to crack 128 bit encryption fast enough to seriously change the state of privacy.

    I have enough sense to make 4096 bit keys whether it's currently necessary or not, but for most people, 128 bit is all they see as needed. This is coded into security apps too much already. In ten years how many people will still be using 128 bit as the "accepted standard", especially with the NSA standing in the way every chance it gets.

  • This thing can do billions of calculations at once.. It can crack RSA in the blink of an eye.. figure out nuclear simulations, DNA decoding and predict the weather.. Can't wait until someone compiles PERL on it.. Onion
  • "Where do you want to go today | tomorrow | yesterday?"
  • I thought the Slashdot readership (regardless of intelligence level) was generally opposed to wanton commercialization. Now we're talking about commercializing QUANTUM COMPUTERS? Get off it already.

    Why the hell would any normal person ever need something like this? "Ooooh daddy, can I get the QZ-5900 please?!?! I want to calculate solar radiation flux! I want to simulate nuclear detonations! I want to solve the traveling salesman problem for 29 billion routes!"

    These are the kinds of problems that quantum computers are geared to compute. Not for playing games, not for doing spreadsheets, and definitely not anything for the store shelves. The only thing that might even tangentially intersect with the common interests is decryption, and I assure you the government will take care of preventing that kind of technology from ever getting into our hands. If we ever see quantum computers in commercial hardware, it will be in very specialized devices that do tasks that 95% of civilization doesn't care about.

  • I would think that a chip like this would be great for PDA's, laptops, just about anything. Really fast, very tiny, and I doubt it consumes any power at all... good deal. I wonder if in even twenty years it will be affordable though. IBM will have to pay off over 20 years of development!
  • See the Perl module Quantum::Superpositions [cpan.org].

    Anyone who went to the Perl conference and saw Damian Conway speak about this will appreciate the phrase "IN CONSTANT TIME!"...

  • Re:Key cracking (Score:1)

    by Anonymous Coward
    i think you're confusing two different key sizes and their meanings.
  • How do you even go about getting the answer of a calculation w/o changing the result?
  • Simultaneous does NOT mean less than one second.

    They could do billions simultaneously, but still take a week (or more) to do it. E.g. if you can walk and chew gum simultaneously, doesn't mean you are walking or chewing any faster.

  • No. Have you ever even read the literature on quantum computation? Sure, it's small, it uses very little power, and it's incredibly powerful.

    But how do you propose we program a quantum device to do everyday tasks? Do think it's as simple as writing some C code? No way in hell. Go read the literature.

  • How the hell am I supposed to overclock this one?

    -ct
  • I should have said billions of operations, not calculations. Thank you for the correction.
  • I understand that a quantum computer can solve a problem in a single step, but how is this possible? Especially if one involved multiple variables or possible outcomes? Would it require multiple problem variants, or something to the effect?

    How is it possible for a quantum computer to do this, but not a conventional one?

  • While it is true that it does take some time, and quite a bit of money to move fabs, it is something that the semiconductor buisness has had to deal with for a long time. The simple fact is, a new fab is really only state-of-the-art for a year or so. It may start out cranking out the money makers, but within a few years they are usually reduced to making either embedded or memory, or something equally non-taxing. And by ten years, all of there equipment has been donated to some university or other, and they are redisgned as office buildings.

    So yeah, it might take sometime for the research, but I would say it would only take a few years after that(assuming Intel/AMD/whoever is in control of chips at the time decides to) before fabs spring up to mass produce these chips.
  • The potential of quantum computing cannot be argued against - the example given shows that it would revolutionize both databases and cryptography.

    I guess that my big question is this: Are these huge benefits only available in these areas, or could this be used to create a faster general purpose machine?

    I know that algorithmic research for these machines is very different than standard CS. Is it just that we've only found good quantum algorithms for these applications? Or is it just that the quantum properties lend themselves to incredible speedups for these specific problems?

    I don't know if anyone here can answer these questions, but I'm sure that some of you know more than I do about it! :)

  • Now who is going to come up with the coolest case for this computer? I was thinking some PVC pipes and a glowing skull...

  • help (Score:1)

    by omay ( 192614 )
    my quantum computer and my cat were in the same box and now the cat is dead. I know because I looked.
  • Even your 4096 bit keys won't be worth anything if this technology scales...

    The significance of Quantum Computers in the field of Cryptoanalysis is that they work differently! For a "normal" computer the time taken to decrypt a PGP messages increases rapidly with the length of the message (was it exponentially?). So a 4000 bit key will not take 4 times as long to decrypt as a 1000 bit key, but many many times as long!

    The Quantum Computer built by IBM however, does it in 1 (ONE!!!) step. So if they can scale it to several thousand atoms, your 4000 bit key is worth nothing... because it will still only take ONE step!!! The only thing they need is a computer with a register long enough to hold your key (4096 bit, possibly they need a bit more..). I imagine however, that this will be quite difficult and that our keys should be safe for the near future :)

    If you wonder how PGP relates to finding the period of a function (which is what IBM found) have a look at this [qubit.org]. I don't understand all the maths... but it seems someone has shown that finding the period of a function can be used to determine the factors of a large number, precisely the problem you face when trying to decrypt PGP!

  • Re:Predictions (Score:3)

    by pigpogm ( 70382 ) <michael@pigpog.com> on Tuesday August 15, 2000 @06:36AM (#854687) Homepage
    Schroedinger's Thinkpad: There is a 50/50 chance that the machine is working or not working each time you open the lid.

    No, wait, that's a Compaq Armada...
  • Well, there are a couple of problems with this...
    1) There have been MULTIPLE critical Windows updates in the past 6 months...one off the top of my head is the "Outlook Sercurity Fix" that was supposed to do away with the ILOVEYOU virus that happend recently...
    2) Just because there are no updates does not mean there are not any problems...what kind of logic is that? It also doesn't mean things are improving. You can't tell me there are no problems with Windows.
    3) While I was busy imagining how long it would be before a *stable* version of Linux came out for it, I thought..."Hey...how long has it been since A *stable* version of Windows came out PERIOD???"
    I would argue more but my computer is about to crash and needs to be rebooted...
  • So is anybody working on a Linux port yet?
  • It is because a quantum bit ("qubit") can be in multiple states simultaneously. This is almost synonymous with simulating "multiple problem variants" simultaneously.

    Here's a good starting point for the non-physicist:

    Quantum Computation: A Tutorial [bangor.ac.uk]

  • Unfortunately, since the task of creating workable and useful algorithms for quantum computers is still in its infancy, I very much doubt present day programmers will ever be able to sit in front on one and hack away at a piece of code. Quantum algorithms are very different from those we use in current computers.

    See QUIC [caltech.edu] at CalTech or the Centre for Quantum Computation [qubit.org] at Oxford for more information on quantum algorithms.

  • And, in fact, has had a working 7qubit computer since March (2000)...

    This article is an easy read with a GREAT summary of the history, applications, and iswsues in quantum computing: http://www.techreview.com/articles/may00/waldrop.h tm

  • As long as it doesn't require any exotic power source, they are welcome to move in. If there is some remote chance in destroying the universe, I'm moving away from Pittsburgh.
  • Think back to the 50's when the semiconductor field was just "some wacky research" that never amounted to anything. In reading about this quantum research, I'm very much reminded of Bob Noyce and Gordon Moore doing their ground breaking work at Fairchild semiconductors. This interview with Gordon Moore [stanford.edu] talks in great detail about the early research years.

    Gordon Moore from the interview:
    Anyhow, while we were making these first mesa transistors, completing development of the process and putting them into production, we had a person whose background was as a theoretician, as part of the original group, by the name of John Hoerni. And particularly when we setting up the initial equipment, John was writing in his notebook and coming up with ideas of things to try, and he came up with a proposal... of instead of making a 'mesa,' which exposes the sensitive area of the transistor to the outside world, that one should just do more of these diffusions--oxide mask diffusions--and leave the oxide over the top of the junction, the sensitive part. Well, that was something that previously had been considered a bad idea because Bell Labs' conventional wisdom was that the oxide was dirty and you wanted to get rid of it.

    But we couldn't try John's idea right away because it took four index masking operations in order to make the structure he was proposing and Bob Noyce only bought three lenses!

    [Laughter.]

  • I thought the Slashdot readership (regardless of intelligence level) was generally opposed to wanton commercialization. Now we're talking about commercializing QUANTUM COMPUTERS? Get off it already.

    Then why isn't it being developed by the government? Why IBM?

  • More Info (Score:4)

    by Trinition ( 114758 ) on Tuesday August 15, 2000 @06:39AM (#854696) Homepage
    Quntum computers aren't terribly new, in the technolgoy timeline anyways. There's beena lot fo development on them, both theoretical and real, in the past 20 years.

    For quite some time, it was just a mind game. That was until real algorithms were discovered/invented to take advantage of these curiosities. With powerfully fast algorithms for factoring large integers (the source of encryption's security), searching, etc. they stand poised to change the face of computing. Imagine things such as cracking 1024-bit encyrtption or searching the entire phone-book in one operation.

    Of course, the tricky part is to build one. Since they rely on quantum properties, they are easily bumped into a real state. But this is the source of their power too. If one particle can be in two states, then a string of particles can represent every n-bit binary number combination possible!

    There are several different ways to go about quantum computing. Some use lasers to cool individual atoms to an energy-level where theyt can be controlled reliably. Others use the bulk-effect of quantum states dtected with nuclear magnetic resonance (ironaically, the caffeine molecule prooves to be particulary useful in this setup).

    As of yet, they've been able to do some pretty simple arithmetic with only a few bits of information.

    As for how it will change computing and programming, the best guess I've heard is that there might be quantum coprocessors someday (much like the old math-coprocessors). You see, quantum computers are thus far very good at certain kind of operations and not so good at others. This is very similar to traditional CPUs (which suck at factoring numbers in a reasonable amount of time). The two compliment each other.

    I knew that information I gleaned while writing that college paper on Quantum Computing would come in handy!

    On a similar note, Quantum Encryption is a related field where quantum-entanglement is used to transmit information securely. If someone were to try and eaves-drop on the system the system would collapse into a real state and the information would not be intercepted.

  • Quantum crypto-cracking (given, say, a 40qubit system) makes cracking traditional crypto insanely easy. IIRC from the defcon quantum crypto talk, it is SQRT(Original keypsace) in difficulty to crack, instead of (Original keyspace).

    This means, longer keys, and eventually quantum computing to enable OTPs (One-Time Pads -- yes, with Quantum computing they're possible, and, better yet, functional!)
  • This looks like it is extending moores law, the amount of qbits is doubling every 18 months or so from 1 to 3 now to 5 then to 10 "in about 2 years or so" Its interesting that technology can keep up with this observation, and whats more amazing was that it was made in the 60's and has held pretty much true for all these iterations.

  • I wish the AltaVista article had some more information about the process. A 5-atom quantum computer is great, but what can it do? I'd be impressed with even a simple "hello" application, or the soution of a simple problem, but AFAICT everyone seems to be waiting for the 7- and 10-atom models.
    --
  • It is true that a quantum computer wourld basically render all crypto schemes in use today obsolete. However, along with the advent of quantum computing comes a crypto that is unbreakable.
    It is based on a concept called Quantum Entanglement. It has been shown that twin photons shot opposite directions down a fiber will, when forced to decide their state, choose the same state at the exact same time. Couple your information to this and you get crypto that cannot be broken because its "key" becomes unusable if grabbed by a third party-the photon is forced to decide state out of synch and kills the message.
  • IBM seems to be doing more research and development than anyone else these days yet they don't seem to be focusing one one or two markets. They are already this big bulky monster. Why are they trying to expand like this?

  • I heard a talk on this about six months ago (when the largest quantum computer was a whopping two bits) and I think it should be made more clear that this type of computer does not do procedural computations (it'd have to be reset every time if I understood right) -- its main application would be mathematical algorithms. The example I was given was in prime-factoring numbers (which is where all of the cryptography comes in), and as far as I know, this is the only use anyone has invented for such a computer.

  • My understanding of it is that you start out with a quantum register (made up of quantum bits) in all sorts of different states, do operations to them until only one possible state is left. Then and only then are you allowed to look at the answer (you can tell what an electron's spin is).
  • It's more of a rule of thumb.

    Quite so, and it was originally something that Mr. Moore (I forget his first name) said sort of in passing during an interview.

    Turns out he was rather insightful (hey, too bad we didn't have Slashdot back then, his karma would have ruled! :), but my understanding is he was just making an off-the-cuff remark that has been accepted as gospel by all the 'tech pundits' out there.

    Cheers......

  • Hmm... one right off the top of my head is GAMES. Quantum Quake, graphics so real it makes current cinematic CGI look fake and ugly. Also, the AI applications would be mind blowing, for games and non games alike. [Think Data from Star Trek]

    BTW, you say not for games, but why not? What, because its enjoyable means it doesn't deserve high tech?

    -={(Astynax)}=-
  • Actually, with quantum mechanics there won't be much of a need for cryptography. I forget the details (we brushed over this in one of those upper-level physics classes that nobody really understands), but it's possible to send quantum information in such a way that any attempts at intercepting would destroy the message. (Something about the transmission being dependant on having only one destination, just thinking about it again is making my brain hurt...)
  • There's no such thing as stable. It's like claiming that the human body's temperature remains constant. Sure, average, it stays pretty close. But your extremities (sp?) are usually cooler than your torso region, and there's always localized variation, as your body carries out exothermic and endothermic reactions all over the place, all the time, for your entire life.

    The same is true for software, especially the various OS's application software runs on. There will always be bugs to fix -- you can't write 14 million lines of code without a bug (Windows 9X is about 14 million LOC I believe) -- the odds against it are just too remote to consider. And fixing some bugs will invariably cause a few more. Factor in new software with new features, new hardware components with their own problems, the device drivers for that hardware, and you begin to see the problem.

    A system can't remain stable for long unless it lives in a vacuum. Computers, Operating Systems, Application Software -- none of these exist in a vacuum. Change is inevitable, and "the Problem" of keeping these things in relative harmony will thus always be with us.

    So, if you can accept that any OS will always have to change, improve, adapt, etc., the question remains as to "which is better." Right now, Linux/Unix/***BSD/Whatever open source will remain a better technical solution -- more people looking at the problem means a higher chance of solving it. Closed souce solutions like WinBlows can't hope to keep up in an incremental fashion. They've done ok so far by enjoying and taking advantage of better hardware/driver support and a better application suite (in most respects), and of course better marketing and a lower learning curve. But, if they lose that advantage, they'll be through. If Office 2000 was available on Linux, there's no reason half the desktops in the US couldn't run Linux instead, almost immediately. The receptionist and the HR staff don't care what OS Word runs on, as long as it's reasonably predicatable and stable and fast.

    I'd keep ranting, but lunch beckons...

    Xentax
  • Well all you ahve to do is learn perl then you can use D. Conway's Quantum::Superposition module, a nice OO Module for using quantum computing in everyday code.

  • quote (Score:2)

    by mirko ( 198274 )
    ``A quantum computer could eventually be used for practical purposes such as database searches -- for example searching the Web could be sped up a great deal -- but probably not for more mundane tasks such as word processing,''
    I really appreciate to see that, though quantum computers could help solving problems, they don't denigrate what came before this.
    This will change from "fashion-effects" that make people forget what was sufficient until something new appeared. For example, look at how quick people got rid of the command line when the first GUIs appeared.

    --
  • I don't know about Windows improving. As far as using Windows Update... I'm lucky if I only have to re-install Windows every month or couple weeks. And what makes you think it will take longer to make a version of Linux stable on a quantum processor than it will for a Windows os? Windows is already *unstable* and Linux is already very *stable*.
  • Since when does the government develop ANYTHING? The government did not develop the space shuttle, the government did not develop the communications satellite, or GPS, or the M16 machine gun, or any number of other things the government has interests in. The government allocates funds for private industry to do the development. This is what capitalism is all about.

    Not to mention that IBM, as a technology entity, has interests in pure research, just like most other huge companies. Despite what you might think, large companies often have humanitarian and scientific interests that are not bound by capitalistic fantasies.

    The example cited in the article about faster web-searching might become reality, then again, it might not. It's still only a single application, and if the time-to-fruition really is along the lines of 20 years as the quantum computing community believes, we'd be idiots to assume that the web will look anything like it does today, or even exist at all, by then. Speculating on how to apply developing technologies to the internet in 20 years is like a person in the 1940's speculating how to apply new propellor designs to new planes in the 1960's, which ended up using air-breathing jet engines instead of inefficient propellors. Except that the internet is changing a hell of a lot faster than that. It's pointless to waste time speculating about the internet in 20 years.

  • I had been wondering how they were going to compile:

    IF (spin_up) AND !(spin_up) THEN

    into anything useful... ;)

  • Re:Predictions (Score:1)

    by Anonymous Coward
    Your quantum computer will exhibit statistical mechanical effects. You cannot predict if you will get a correct answer, only the probability it is correct. No, wait... that's a Pentium floating point unit.

  • I want to calculate solar radiation flux! I want to simulate nuclear detonations!

    Why the hell wouldn't you!!?! Video games man!

    ID Software are you listening?

    Quake7 - The End is Here Real world destruction in real time. You cerbal cord will twitch at the realism and your well ajusted mind will melt in trying to determine what is real, and what is just the video game. (Requires Windows XII, Ultra Linux 7I or MacOS 9.1)

  • Re:Programming Quantum Computers (Score:3)

    by ikoL ( 159552 ) on Tuesday August 15, 2000 @06:59AM (#854715)
    I wonder how much different it will be, and how us "old-timers" will deal with it.

    Digital computing won't go away though, as the article mentions, quantum isn't good for many tasks. Most likely they'll come out with hybrid machines, a digital machine calling on the power of the quantum processor when needed. Sorta the way a gas-electric hybrid uses the better engine for a given speed. I'd think that you'd have a digital processor calling on a quantum one when the problem warrants it's power. Digital programmers'll write programs for the digital one and call the "quantum functions" via an API.

    but then again I could be compleatly wrong

    -ikoL

  • Language for quantum computers (Score:5)

    by AlpineR ( 32307 ) <wagnerr@umich.edu> on Tuesday August 15, 2000 @07:00AM (#854716) Homepage
    While searching for quantum physics simulations, I came across

    A Programming Language for Quantum Computers [tuwien.ac.at]

    There is also a good, comprehensive website at

    OpenQubit [openqubit.org]

    but it seems to be in need of a new maintainer.

    My understanding is that quantum computer simulators allow one to mimic the output of a quantum computer, but without the time speed-up that real quantum hardware would provide. So algorithms can be tested out, slowly, even before powerful quantum hardware is developed. I suspect some problems can also be better expressed in a quantum computing language and would therefore be solved more easily even on classical hardware.

    On the subject of simulating quantum physics on classical hardware, in the book The Feynman Processor and in Feynman's own papers it is stated that a classical computer can never perfectly simulate quantum physics. But from the evidence they give it seems merely impractical, not impossible. There can be a huge penalty in the number of steps and time required but no clear reason why a simple quantum physics system could not be perfectly simulated on a powerful classical computer. Anyone have any insight on this problem?

    AlpineR

  • This is true--and is the OTP effect.

    The problem is the tech curve. There is no way in hell that we'll have desktop end-to-end quantum crypto devices before spooks and other nefarious types get decently strong qubit computers to ravage all current encryption.

    This would explain the lowering of export requirements for traditional encryption...

  • the classically trained are doomed (Score:5)

    by Sebastopol ( 189276 ) on Tuesday August 15, 2000 @07:02AM (#854719) Homepage
    Word: If you're between the ages of 14-18, START STUDYING QUANTUM COMPUTING NOW!!!

    Why? Long explanation:

    I read half of a book called Introduction to Quantum Computing (can't remember the author, but I bought it at Siggraph'99 -- there was a huge pile of this book in one booth).

    Anyway, the book is great. It's almost a step-by-step guide to the math behind quantum computing while still maintaining the physical analogy. I got to the part where they discuss Feynman's method for building a quantum adder (which was merely a trivial demonstration of how to get a QM to do a classical computation).

    In chapter 5 or 6, the book starts explaining how to build a Hamiltonion (QM operator function, kinda like a Laplace transfer function H(s)) for the square root of a NOT gate, I realized that anyone who's brain has been fed classical computing concepts based on Turing and Von Neuman is DOOMED to not grok this stuff (or perhaps it's becuase I'm almost 30 and my brain has turned to sand). It's kinda like trying to go from C to LISP.

    So kids, that's why I recommend that you start growing the synapses now. Start growing the synapses that will help you understand this stuff before the patterns of classical computing cure in your young gray matter.

    (Yeah I love how every reporter goes from: "Fascinating new qubit which is 0 and 1 simultaneously because of spin..." to "...so the qubits add all of the numbers at once to find the asnwer in one step". If you can't explain something in a 5th grade english, you don't understand it.)


    ---

  • History shows the way... (Score:4)

    by slothbait ( 2922 ) on Tuesday August 15, 2000 @07:04AM (#854721)
    I want to calculate solar radiation flux! I want to simulate nuclear detonations! I want to solve the traveling salesman problem for 29 billion routes!

    You know that's exactly the sort of thing that the old Crays were used for. That was back in the day when "supercomputer" meant something, and these beasts only existed in ones and twos in places like Los Alamos, Sandia, and maybe Exxon.

    And back then people thought the exact same things that you are saying now. "Who other than a weapons research lab could possibly use this"? The answer that surprised people is "just about everyone". The Cray-1 may be an inert piece of history now, but it's spirit lives on in our microprocessors. It's not just that modern PC's are as fast as old supercomputers, they are designed like old supercomputers.

    Most innovations in computer architecture in the PC/workstation/server area have been taken from the supercomputers that came before. Surely the original researchers never dreamed that all of the complicated methods they were inventing to speed up supercomputers would wind up running some kid's game -- but they have.

    Modern systems are blazingly fast, yet people continually feel the need to upgrade. In the PC biz, this seems to be driven by games and MS-bloat. Whatever the case, technology marches on, and people are willing to pay for more power. If you have the transistor budget, why not build a supercomputer on a chip? There's a market for it.

    My point (such as it is) is that the hunger for performance shows no sign of stopping. It may seem ridiculous to us that an average person could ever use this much computing power. But bear in mind, that this won't even hit supercomputers for ~20 years. Think what people ~20 years ago would think about the kind of computing power that we use for games today. They would be stunned.

    A little historical perspective, that's all...

    --Lenny

  • Quantum cryptography beats quantum cryptanalysis (Score:3)

    by Fervent ( 178271 ) on Tuesday August 15, 2000 @07:13AM (#854732)
    In The Code Book [slashdot.org], they diagram how quantum cryptography is going to easily beat quantum cryptanalysis.

    True, it's easier to break traditional prime-number based ciphers with quantum machines, but there is an effectively unbreakable cipher which can be built off a quantum computer - one that relies off the position of the atoms used as they fly through refractors that "trap" the states, and a system that relies on public-key ideas to keep that atom key a secret.

    They cite quantum money as a potential example (an idea developed in the 1970s). There are some truly mindblowing consequences to an unbreakable cipher.

  • Re:5 Atoms? (Score:5)

    by bob_jordan ( 39836 ) on Tuesday August 15, 2000 @07:20AM (#854736)
    Dropping contact lenses is bad enough. Imagine dropping one of these!!!

    "NOBODY MOVE!!!!!"

    Bob.
  • What's the betting that there'll be a story on C|Net tomorrow where some IBM research guy claims that they're considering porting Linux to this thing "just to see how small it can scale down"?
  • "...unfortunately, we won't see them on the shelves for about 20 years."

    You're predicting we'll be able to see 5 atoms on a shelf in 20 years?!

    Cool! That's a bigger story than the quantum computer!

  • The example I was given was in prime-factoring numbers (which is where all of the cryptography comes in), and as far as I know, this is the only use anyone has invented for such a computer.

    This may seem incredibly short-sighted, but what's then to stop us from putting a quantum-computer-on-a-card inside of a traditional computer to handle those sort of problems?

  • The significance of Quantum Computers in the field of Cryptoanalysis is that they work differently! For a "normal" computer the time taken to decrypt a PGP messages increases rapidly with the length of the message (was it exponentially?). So a 4000 bit key will not take 4 times as long to decrypt as a 1000 bit key, but many many times as long!

    The Quantum Computer built by IBM however, does it in 1 (ONE!!!) step. So if they can scale it to several thousand atoms, your 4000 bit key is worth nothing... because it will still only take ONE step!!! The only thing they need is a computer with a register long enough to hold your key (4096 bit, possibly they need a bit more..). I imagine however, that this will be quite difficult and that our keys should be safe for the near future :)

    The question, as you mention, is whether is is practical to set up a 4000-qbit computer such that the quantum entanglements of the 4000 qbits cause the right solution (e.g. the factors of a specific 4000-bit number) to pop out of the collapsed state. The slow crawl from 2 qbits to 5 qbits to 7 qbits suggests to me that it might turn out that the difficulty of setting up a 4000-qbit computer for a given problem isn't much less than the difficulty of just solving the problem algorithmically.
    /.

  • Man, think of the purchasing scams you can pull at your company.

    "Bill, I want to talk to you about this 20 million dollar hardware acquisition charge. All we got was this box with foam kernels in it"

    "You opened the box?! You fool! You let all the quantum computers out! Now I'll have to reorder them! The board will hear about this!"

    Later
    Erik Z

  • I have to admit first off here that I haven't read up as much as I should about quantum computing. Nontheless, I find myself wondering: what will it be like writing software for a quantum computer? Will quantum machines even be stored-program computers?

  • All those cycles...hmmm could it be sentient? Starting to sound a little like Sid 6.7.
  • Well then, i guess we'll just have to start generating 40960 bit long keys in order to stay ahead of "them".

    You don't seem to get it. A quantum computer in effect "knows" the answer right at the beginning and it just takes a little bit of time to display it. If quantum computers were to ever become stable enough to have the ability to run something like linux at the speed of a Pentium, your 40960 bit long key would be rendered useless in minutes if not seconds.

    A very simplistic way to look at it is you have a room with n switches, where n is the number of bits in you encryption, and some lights connected to those switches. In order to have all of the lights on you need to have those switches in a specific order. A regular computer flips the first switch, turns around and checks to see if the lights are on, if not moves on in a binary fassion (there are better ways of doing it but this is just a simplification). It will go through all of the combinations until it hits the correct answer. A quantum computer has the equivelent to a cheat sheet with the answer on it already and it only takes enough time to flip the switches in the correct order.

    Standard cryptography today is useless against quantum factorization. Luckly, right now there is no way to keep the particles in a stable configuration. If you think that large bit encryption will keep you safe from quantum computers, when they finally become viable, then you are asking for you messages to be broken.

  • Re:Why would we EVER see them on shelves? (Score:3)

    by ErikZ ( 55491 ) on Tuesday August 15, 2000 @08:30AM (#854769)
    >These are the kinds of problems that quantum computers are geared to compute. Not for playing games, not for doing spreadsheets, and definitely not anything for the store shelves.

    Whew! I'm glad you figured it all out for us. You saved everyone a lot of time and money by letting us know what what we shouldn't be doing with quantum computing.

    Oh, but I think you're wrong on games, I believe you'd be able to program some incredible AI for games like Quake, Or do fantastic universe simulations for games like Elite or privateer.

    You're right about the spreadsheets though, who needs spreadsheets when you have have a quantum computer go though all the possible combinations of funding for a company to come up with the best fiscal plan, in about two seconds.

    And I'd hate to have one of these things on my desktop, I mean, I'd be playing with it all the time, trying to find out new things that could be done with it. Working together with other cutting edge geeks out there...I mean, what's the point?

    Sheesh,
    Erik Z
  • Part of the reason for the slow crawl from 2 to 5 to 7 qbits is a stability issue. Right now quantum computers have a lifespan of a mere fraction of a second. The ability to keep the qbits in a stable enough configuration such that they can be used for long periods of time has not been found yet. Once they find out how to stablize it then the scaling becomes relatively easy, so long as they can keep it cooled properly (and for those who don't know were talking liquid helium temperatures ie under 10 Kelvin).
  • Accually your more right than you know. As quantum computers solve problems, they can only produce answers that they are some order of mangitude (lets say 95%) confident in the solution. So statistically it should give you the correct answer 95% of the time, the other times the answer will be completly wrong. But thats where traditional computing has its place, as it takes almost no time for a regular processor to check the answer of the quantum processor, and tell it to try again.

  • P=NP (Score:2)

    by Undaar ( 210056 )
    Maybe this will finally help me solve P=NP...

    Right now my solution:
    P=NP where N=1 just doesn't seem to work...
  • It is true that a quantum computer wourld basically render all crypto schemes in use today obsolete. However, along with the advent of quantum computing comes a crypto that is unbreakable.
    Crypto has many uses aside from strict confidentiality. It is also useful for authentication. Sending messages to people you've never met (web-of-trust). Digital cash. ...and more. So the "quantum cryptography" isn't a replacement for the types of cryptography that are impacted by quantum computing (namely public key systems).

    Burris

  • I can just imagine that sometime in the future (if it doesn't exist already) there will be a quantum programming language called Q-BOL.

    These opinions are my own and not necessarily

  • Yeah, right. I remember when the Compaq Deskpro 386 came out. "That'll make a great server, but nobody really needs a workstation that fast." So naive. In 20 years, the a.out from hello.c will be 50 megabytes, and you'll need something with a the power to simulate a nuclear explosion just so that MS Word will be able to keep up with your typing speed.

    I know. You think I'm joking, or that I'm wrong. But I'm not. Try MS Word 2000 on a Pentium 66 some time and see if it can keep up with your fingers. In 1990, you would have laughed at the idea that computers were going to be slower in 1995 than they were in 1985, but guess what? It happened. Ain't software "progress" great?

    20 years from now you're going to be begging on your knees for one of these quantum computers just so you can read your email without falling asleep while waiting for the screen to redraw. And in 2023 your "old" quantum computer will be totally obsolete.


    ---

  • This part of the book is very "mathematical" and its conclusions must be regarded as true.

    Actually, many reseachers, in both physics and AI, do not regard it is true. And the question of "intelligent computers" is still an open one.

    Just because something is mathematical doesn't make it true. It may follow from the assumptions, but it is Penrose's assumptions that are in dispute.

    See Dennet's Consciousness Explained for an example of a viewpoint opposed to Penrose's.

    Steve M

  • This "quantum computer" is actually a vial full of mole quantities of different quantum computers. You poke at them with radio waves to program them and then use an NMR to read the results, which are a vote by all of the molecules.

    That's fine, as long as 10^23 votes is enough to overwhelm any errors. But for a serious number of qubits, the unavoidable chance of quantum bitflip in each atom means that eventually less than one of those 10^23 molecules is in the correct starting state. Perhaps you can solve this by quantum error correction - the algorithms aren't worked out yet - but that multiplies the number of bits needed for a given problem by a factor of (provably) 2 or (probably) 3. Then you have the problem that any operation can only involve closely neighboring bits; to add register A to register C requires huge numbers of operations to shuffle with register B. Finally, to read or write to any given bit, you need a unique frequency to address that bit. With hundreds of bits, only a few can possibly have frequencies that stand out enough. These problems, combined, add one or more factors of N to the resources necessary; it's still polynomial, but...

    Quantum dots - single particles, NOT entire atoms, confined electrically to a single quantum state - are more hopeful. Because they can be physically rearranged or put in more complex configurations and still physically addressed on an individual basis, the problems above go away or become more manageable.
  • It is true that a 5 qubit quantum computer is useless against a 40 bit key, but if they every get the stabilization problem fixed we won't be dealing with 5 or 7 qbit machines because they will scale the things rather quickly. You can only scale so high with the standard mathematical encryption algorithms.
    Don't brush quantum computing aside because it will come to nip you in the butt before you know it.

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