Follow Slashdot blog updates by subscribing to our blog RSS feed

 


Forgot your password?
Close
typodupeerror
×
Science

Molecular Photography 226

Posted by michael from the say-cheese dept.
med dev writes "An article at New Scientist discusses the latest in quantum computing - 1000 bits stored in the electron spins of a single polymer molecule. Add in a recent release of the how-to for the complete quantum computer, qubits that work, and it may not be much longer before Google is running on a server the size of a sugar cube."
This discussion has been archived. No new comments can be posted.

Molecular Photography More

Molecular Photography

Comments Filter:

  • Not necessarily a good thing... (Score:5, Funny)

    by Doctor Sbaitso ( 605467 ) on Sunday December 01, 2002 @10:08PM (#4790419) Journal
    it may not be much longer before Google is running on a server the size of a sugar cube

    "Hey Johnny, where did the new $100,000 server go?"

    "I don't know... I had it right here on the table!"

    "Oh shit! I put it in my coffee! That's why it tasted kind of funny."

  • Great (Score:2, Funny)

    by Anonymous Coward
    But these molecular photos are so tiny. I can barely see them without my glasses.
  • ...is it clean in other dimensions?

    • Re:Regarding this "Quantum Computer"... (Score:5, Funny)

      by Anonymous Coward on Sunday December 01, 2002 @10:28PM (#4790511)
      Apparently quantum computers "borrow" exponential scratch space from some Hilbert space during computation. As far as I know, there's no one living in Hilbert spaces that it could upset, but I could be wrong. So at worst it's a victimless crime, like punching someone in the dark.

  • Molecular computers may benefit from this... (Score:3, Interesting)

    by saskboy ( 600063 ) on Sunday December 01, 2002 @10:10PM (#4790429) Homepage Journal
    Does anyone know if Synchrotrons, like the one in Saskatoon, SK, Canada play a part in researching molecular computers? The article mentions a magnetic imaging device. Is that like a synchrotron?
    • When I hear magnetic imaging device I think MRI, or cat scan...

    • Re:Molecular computers may benefit from this... (Score:5, Informative)

      by nounderscores ( 246517 ) on Sunday December 01, 2002 @11:21PM (#4790715)
      Synchrotrons are used for x ray crystalography [llnl.gov]. they can produce X-ray photons at a wide range of frequencies and you can carefully select the photons you want using an x-ray monochromator.

      The X-rays will not tell you anything about the nuclei of the molecules you are looking at, as the photons go through the electrons in the crystalised protein they will make an interference pattern, and from that you can calculate the shape of the electron cloud around the molecule.

      Note that this gives you no infomation on the quantum state of the nuclei, which is what this quantum computer needs to know.

      Nuclear Magnetic Resonance [rit.edu] molecular analyisis works in a similar way to Magnetic Resonance Imaging, just on a smaller scale.

      for more information click here [rcsb.org]

    • Easy answers. (Score:3, Informative)

      by k98sven ( 324383 )
      Does anyone know if Synchrotrons, like the one in Saskatoon, SK, Canada play a part in researching molecular computers?
      No, not at all.

      The article mentions a magnetic imaging device.
      Is that like a synchrotron?
      No, not at all.

      Syncrotrons produce gamma/X-rays. Expose a polymer to some of those, and it won't stay a polymer for long..
      NMR instruments (and MRI devices) use radio waves. Much longer wavelength, much lower energy.
      The only similarity I can think of is that both use big magnetic fields, but for different reasons.
      (syncrotrons use them to accelerate particles, NMR machines use them to split the spin energy levels)

  • Nice, Cool, Wow, but...... (Score:4, Insightful)

    by TechFaerie ( 568490 ) on Sunday December 01, 2002 @10:11PM (#4790430) Homepage
    So the scientists have succeeded in encoding a tiny black and white picture on a polymer molecule. Hooray! Another tiny step for science, but a giant leap for mankind. However, realitically, I don't think Google will be running on a sugar-cube sized memory bank any day now. The money to move that kind of infrastructure onto a quantum computer is unthinkable.

    So, a wonderful step forward....but there are still many many steps left.

    Sincerely, your local cynic

    • Re:Nice, Cool, Wow, but...... (Score:5, Insightful)

      by Big Mark ( 575945 ) on Sunday December 01, 2002 @10:18PM (#4790465)
      "One small step for [a] man, one giant leap for mankind."

      It all depends on your perspective. Give it a while and we'll see what the true ramifications are.

      -Mark

      • Re:Nice, Cool, Wow, but...... (Score:5, Interesting)

        by delta407 ( 518868 ) <slashdot@nosPAm.lerfjhax.com> on Sunday December 01, 2002 @11:52PM (#4790828) Homepage
        It all depends on your perspective.
        No, it doesn't. There are a lot of technical hurdles to overcome with quantum computing, and this article discusses very few of them.

        For instance, it mentions that they used photons to carry information between ions. That's all well and good, but remember, working with single photons isn't all that easy to begin with, and that pesky Heisenberg guy keps getting in the way. Stray particles remain a problem. (Silicon computing has copper to carry electrons -- what do you to with individual photons?) Furthermore, it does not address the larger problem of decoherence, wherein the state of a quantum computation is lost after a short and unpredictable amount of time.

        Really, what would be better is some great leap in quantum error correction or some quantum computer that does not rely on nuclear magnetic resonance. (NMR can only scale to seven or eight qubits before becoming unusable, at which point quantum computers are rather pointless...)

  • hmm... (Score:2, Interesting)

    by ender's_shadow ( 302302 )
    doesn't hitting it with the second radio burst kill the conformation you've made with the first?

    and isn't the first conformation likely to change spontaneously anyway (we're only talking about spin here, not orbitals). maybe they sit in the middle conformation or something, like benzene double bonds ...

    i can feel the organic chem rusting in my brain weekly; it's almost gone now ...

  • Access Speed. (Score:5, Informative)

    by Trusty Penfold ( 615679 ) <jon_edwards@spanners4us.com> on Sunday December 01, 2002 @10:13PM (#4790443) Journal

    nuclear magnetic resonance (NMR) instrument.

    I've done NMR, it takes ages. Preparing the sample takes about 30 minutes. Running the NMR takes between 1 and 20 minutes depending on what you're measuring. Analysing the results depends on how good you are.

    I can't see google using this any time soon.

    • Re:Access Speed. (Score:2, Interesting)

      by Anonymous Coward
      Hmmm... you're being rather short-sighted here. This is not NMR like you've done.

      I posted elsewhere in this article about NMR... if you want some details on how it's done, read my other post.

      Anyway, they aren't using a commercial NMR device that you'd see in a biology/chemistry lab. I don't understand how it works myself, because I don't see determinism embedded in qubits, which have a random element.

      The point is, they aren't measuring chemical shift, which is what it sounds like your NMR experience involved.

      I get the impression they don't look at relaxation times at all. They are more interested in the bulk spin-state of the material, not in the interaction between the atoms in the material.

      Down with Saudi Arabia!!!

    • Re:Access Speed. (Score:2, Informative)

      by k98sven ( 324383 )
      I've done NMR, it takes ages. Preparing the sample takes about 30 minutes. Running the NMR takes between 1 and 20 minutes depending on what you're measuring.
      Analysing the results depends on how good you are.

      That's a bit silly. The actual pulse sequence doesn't take anywhere near 1 to 20 minutes, more like microseconds.
      You repeat the thing to get better resolution, which may not be necessary with better equipment in the future.
      Not to mention that analysis can be automated as well. (It already is when it comes to protein-NMR)

  • 1000 bits... (Score:5, Funny)

    by Lu Xun ( 615093 ) on Sunday December 01, 2002 @10:17PM (#4790460)
    If they could just fit 24 more on there, it would be a much easier number to work with...

    • Re:1000 bits... (Score:3, Informative)

      by SeanTobin ( 138474 )
      If they could just fit 24 more on there, it would be a much easier number to work with...

      Blockquoth the article:
      Bing Fung and colleagues at the University of Oklahoma found that the 19 hydrogen atoms in a lone liquid crystal molecule can store at least 1024 bits of information.

      They did record at least 1024 bits. But I guess they aren't being used, because otherwise, /. would have sentient beings checking facts, grammar, and spelling before posting.
  • I have to wonder what type of redundancy and error correction will have to be built into quantum computing. With all sorts of EM disturbances that are recoverable in atomic-level computing like we have today, what will happen when we go that small? I'm not necessarily asserting that it will happen, but that we need to understand the phenomena in all sorts of usage, including high-altitude applications and cosmic rays. The one thing we take for granted in modern electronics, particularly storage devices, is their hard resiliency to soft errors (i.e. soft errors don't necessarily translate to hard errors).

    • Re:Redundancy of information stored? (Score:4, Informative)

      by nihilogos ( 87025 ) on Sunday December 01, 2002 @11:21PM (#4790714)
      I have to wonder what type of redundancy and error correction will have to be built into quantum computing.

      Lots and lots. In 1995 Peter Shor (the factoring guy) and Robert Calderbank devised that possible [lanl.gov]the first error correcting code for quantum computers. Many others have been designed, including proposals for some that operate as a natural consequence of the system being used. Here [lanl.gov] is a good survey of the field.

      It has been shown that if the error rate is below a certain threshold (currently estimated to be one error per 103 operations for optimists, and one per 106 per pessimists) then efficient error corrected quantum computation is possible. The pessimistic estimate is well above what is currently possible experimentally in quantum systems but the problem seems to be an engineering one, not a fundamental one. It should eventually be possible with clever implementations of qubits, shielding and cooling to near absolute zero.
    • With all sorts of EM disturbances that are recoverable in atomic-level computing like we have today
      Ah, yes, the people that buy ECC RAM [www.drix.be] to correct for alpha-particle variations and so on.

      I have to wonder what type of redundancy and error correction will have to be built into quantum computing. ... I'm not necessarily asserting that it will happen
      Such variances are common and expected in quantum computing; hence the field of Quantum Error Correction [qubit.org]. (Google for more [google.com]...)

  • Popular science (Score:5, Informative)

    by vlad_petric ( 94134 ) on Sunday December 01, 2002 @10:28PM (#4790512) Homepage
    Most people don't realize that a quantum computer can't function by itself, i.e. it needs a traditional "front-end". This is mostly due to the fact that quantum circuits can't form cycles, and in order to have a Turing-complete system you need at least 3 loops on top of each other.

    Moreover, the peculiarities that make quantum computing interesting (e.g. the ability to factorize in polynomial time) also make it completely inappropriate for mundane tasks. So please stop the "google in a cube" shit.

    • Re:Popular science (Score:4, Informative)

      by nihilogos ( 87025 ) on Sunday December 01, 2002 @10:59PM (#4790623)
      Most people don't realize that a quantum computer can't function by itself, i.e. it needs a traditional "front-end". This is mostly due to the fact that quantum circuits can't form cycles, and in order to have a Turing-complete system you need at least 3 loops on top of each other.

      What the hell are you talking about. Although it will undoubtably more practical to use a classical computer to run one of the current envisions of a quantum one, that doesn't mean the classical one is required. Quantum computers include classical computers as a subset.

    • You are wrong - Re:Popular science (Score:5, Informative)

      by MobyDisk ( 75490 ) on Sunday December 01, 2002 @11:34PM (#4790764) Homepage
      ...the peculiarities that make quantum computing interesting...also make it completely inappropriate for mundane tasks. So please stop the "google in a cube" shit.

      You are incorrect. Classical computers can search an indexed database in log(n) time. Grover's algorithm allows quantum searches to be much faster, perhaps even in constant time. Search engines could benefit immensely from quantum computing.

      Lots of information can be found on Lov Grover's quantum search algorithm. Do a search for it on Google. Dr. Dobb's even analyzed the quantum source code [ddj.com] for the algorithm. Pretty cool stuff.

      • Either there is new Grover's algorithm or you misunderstood something.
        The original Grover's algorithm is for searching in unsorted database. Grover has shown that this takes only O(sqrt(n)) steps as opposed to O(n) on classical computer.
        Grover's algorithm does not deal with sorted or indexed databases and I don't think it can be adapted to make advantage of the order of database elements. What it does is simply taking advantage that you can quickly enhance the probability of choosing element matching your search criteria from all possible elements.

        To summarize: as far as I know noone has shown deterministic nor quantum search in ordered set to be below O(log n) in worst case.
      • Much obliged for the pointer, but I do have a question. I'm probably overlooking something simple here, but...Grover writes that we're limited to "reversible" gates, i.e. those for which one can infer the inputs from the outputs. NOT is obviously reversible, but it seems that the pigeonhole principle would prevent any gate with more than one input from being reversible (there are 2**n possible n-bit inputs, but only two possible one-bit outputs). What am I missing?
        • Grover writes that we're limited to "reversible" gates, i.e. those for which one can infer the inputs from the outputs... but it seems that the pigeonhole principle would prevent any gate with more than one input from being reversible

          You can turn any irreversible gate into a reversible one by adding outputs. For example, 2-input XOR becomes reversible if you add a 2nd output which is a copy of one of the inputs. There are many tricks like this which are studied under the topic of reversible computation.
      • And if you want to feel *really* stupid, take a look at this [znaturforsch.com].

        http://www.znaturforsch.com/57a/s57a0701.pdf

    • Re:Popular science (Score:5, Insightful)

      by Idarubicin ( 579475 ) on Monday December 02, 2002 @12:57AM (#4791044) Journal
      Moreover, the peculiarities that make quantum computing interesting (e.g. the ability to factorize in polynomial time) also make it completely inappropriate for mundane tasks. So please stop the "google in a cube" shit.

      This article is about storage, not processing. And quantum bits of this type are pretty damn dense. Guess what--Google needs to store a lot of data. Yes, the experiment described isn't much more than an interesting proof-of-concept, but there is tremendous promise. "Google in a cube" is a bit of journalistic license, but I'll still be impressed when we're putting just the Google cache into a sugar cube.

  • To the future. (Score:5, Interesting)

    by OpenGLFan ( 56206 ) on Sunday December 01, 2002 @10:33PM (#4790524) Homepage
    To everyone who has so far commented: so what?
    My mother was born in 1947. The transistor was also invented in 1947, by Shockley. 55 years later, I got her a new computer for Christmas.

    What will I see when I turn 55? I can't wait to find out.

  • Database indexes (Score:3, Interesting)

    by whereiswaldo ( 459052 ) on Sunday December 01, 2002 @10:34PM (#4790533) Journal

    Will quantum computing make using database table indexes obsolete? ie. will the time saved by using an index be small enough that it's not worth the effort to create/maintain one (for most uses)?

    Sounds like "what-if" analysis will be taken to a new extreme, big time.
    • Uhm, probably not.
      I am still waiting for quantum computing to defeat all currently existing encryption mechanisms by easily solving all infeasibly difficult problems.

      I guess there are some practical hurdles which I don't understand.

    • Will quantum computing make using database table indexes obsolete? ie. will the time saved by using an index be small enough that it's not worth the effort to create/maintain one (for most uses)?

      No. Grover's quantum search algorithm searches an unindexed database with N entries in O(sqrt(N)) time. It says nothing about indexed databases which can be accessed in O(log(N)) time using classical computers.
      • Grover's algorithm would not be used in 'database searches' as we know them (like looking up numbers in a phone book). Given only y = f(x) and y, solving for x is an O(n) function (brute-force of the possible inputs). That in mind, Grover's algorithm allows for such a search in O(sqrt(n)) time, which is why it's so impressive.

  • ok... (Score:4, Insightful)

    by Transcendent ( 204992 ) on Sunday December 01, 2002 @10:47PM (#4790575)
    so we can store information on a molecule, but how big was the machine that created the spins? And how long did it take to process the 1's and 0's on the molecule?

    Sure, we could store information on molecules, but the speed and the size of the machines involved would put us back to working with punch cards...

    What needs to be done simultaneously is to improve the method in which we induce and read the spin in molecules, or those sugar cube sized computers will just be expensive and slow RAM inside a computer the size of a room...

    • True, it probably takes a massive machine to make the itty-bitty data storage. Until they can miniaturize that equipment, though, I'm sure there will still be a good market for massive ROMs. Lots of read-only storage in a little container. Of course, the access device has to be small enough, but I can see a middle-ground.

      Industrial CD-pressing machines are pretty huge, but the read-only data they create is incredibly mobile.

  • pocket sized google?
    Imagine a beowulf cluster of these
    "ducks"

    I wish my computer were the size of a suger cube, lan parties would be easy, just stick my computer in my pocket and go though a suger cube monitor might not be as nice.......

    "hey stop shooting at my I droped my magnifying glass"
  • Comment removed based on user account deletion

  • Wow.. (Score:2, Funny)

    by Anonymous Coward
    Imagine a RAID array of sugar cubes. That'd be sweet!
  • So how many library of congresses will fit into one sugar cube?
  • A server the size of a sugar cube would be pretty sweet.
  • I strongly believe that in conjunction with nanotech and biotech, quantum computing will allow human beings to create brains more powerful than their own. These "machines" will evolve over the next 100 years or so, until they are so much smarter than us that they won't need us anymore. All of mankind will be destroyed and a new conciousness will take over the world, the solar system, the galaxy, and eventually, the entire universe. It will grow, learn and evolve until it becomes the whole universe, and then it will modify time to get rid of our existance altogether, so it will be like we never existed. Essentially, we only perceive that we're here. We actually don't exist. I have bulletproof evidence that all of this is true: The other night, while my buddies and I got puke-drunk at the local bar, two different people who claim not to know each other told us what I just told you. It is undeniably the primary truth of the universe.

  • Translation (Score:5, Informative)

    by dragons_flight ( 515217 ) on Sunday December 01, 2002 @11:24PM (#4790730) Homepage
    I'm a physics graduate student, and while not in any way affiliated with this work, I think I understand the article well enough to explain it and hopefully clear up many of the confusions I'm reading here.

    First off, this is NOT a quantum computer. It does not use qubits. The current experiment is about encoding plain old binary bits onto a molecule. Molecules are made of atoms, and each atom has a nucleus (surrounded by electrons), and each nucleus has a "magnetic moment", which means it acts like a little bar magnet. The "spin" of the nucleus tells you which direction that magnet is oriented. (Okay, spins are more complicated than this, but this is the important bit in this experiment.)

    Now, electromagnetic radiation (light, radio waves, X-rays) comes in a continuous array of forms, but all of them can be described (to some approximation) as being made up of alternating electric and magnetic fields. These alternating magnetic fields can pull on the magnetic moments of nuclei and reorient them (i.e. change the spin). Now for a complicated molecule, all the little nuclear magnetic spins from all the different atoms will interact in determining the final state when some electromagnetic radiation is applied. (Imagine that the different magnets pull on each other even while the radiation pulls on them.)

    What the researchers did was choose 1024 distinct frequencies of electromagnetic radiation that were in the right range to affect the spins, and then showed that the final magnetic state for the molecule depends (presumably uniquely) on the which subset of radiation they applied. For instance, if you wanted to encode 01110101000...0, then you would bombard the molecule with the 2nd, 3rd, 4th, 6th and 8th frequency.

    In order to measure the resulting state, they applied an NMR (nuclear magnetic resonance) measurement, apparently to measure the difference in magnetic fields from the recorded state and the way it reacts to a particular applied field (the article is a little vague on these details).

    So to make a long story short, they rearrange the nuclear spins of a particular molecule using an applied electromagnetic field and then invented some way to measure the resulting configuration, and showed (or more likely inferred from testing some subset) that they can make at least 2^1024 distinct configurations by varying the field you apply, hence showing that it is possible to encode a 1024-bit number.

  • Before some spits out the blatantly obvious. (Score:3, Interesting)

    by reelbk ( 213809 ) on Monday December 02, 2002 @12:00AM (#4790857)
    Someone always has to state what common logic implies. Therefore, I know there's going to be some guy posting something along the lines of "I don't think google can switch their whole system to something as small as an sugar cube! That would cost too much! I'm a massive tool.". Here's how something like this really works:

    It's not likely that a quantum computer will be of any use as a desktop computer (not anytime soon). They just don't work that way.

    A quantum computer works by exploiting a phonomenon explained by QM - the superposition of states. Basically, a particle takes on every possible state it can be, as long as it isn't measured. (google Schroedingers cat if you want a good analogy). So basically, if you have an 32-qubit register, you can represent 2^32 states. What makes the qubit different than the classical bit is that all these states exist at the same time. Therefore, your system is exponentially parallel.

    This massive parallelism makes them extremely useful in problems that requires massively parallel processing, such as searching algorithms, factoring, and any other NP problem. Their first applications may very well be in a system such as google's, but it'll most likely be in the form of a co-processor. It's pretty safe to say that all quantum information processing systems will only be used to solve such problems. Once they mature and we figure out ways to stop decoherence, then maybe they'll become a consumer item. Until then, they're researcher's dream.

  • NSA likes this stuff (Score:5, Interesting)

    by dragons_flight ( 515217 ) on Monday December 02, 2002 @12:02AM (#4790859) Homepage
    I did undergraduate work at the University of Maryland [umd.edu], and had an opportunity to meet Bruce Kane, who is mentioned in the "qubits that work" article.

    It's no surprise that his idea was implented by a group in Australia, since he was originally a researcher there. However the University of Maryland and more importantly the NSA [nsa.gov] convinced him to come over here. The Labratory of Physical Scientists [umd.edu] (LPS) was set up only a few years ago to pursue cutting edge work in quantum computing and related fields, with a rich endowment from the NSA.

    More precisely, the group says they can effectively buy any piece of equipment they want with the money the NSA is willing to dole out to ensure that the US has the lead in this technology. This includes having one of the most advanced clean rooms and chip fabs outside of industry.

    I know of no direct evidence to support my claims that the NSA is bankrolling LPS but the site is only a 15 mins from the NSA headquarters in Fort Meade, MD, and there is a reason that LPS chose a KEY for their logo. After all wouldn't it be fun to unlock all the secret codes.
    • It's funny to see the NSA sponsoring research in quantum computing... They're only going to give themselves headaches once practical systems are developed because prime factoring won't be hard anymore. But I guess its better to start the research now and get all the best minds on their side. That way they stand a chance at developing new encryption systems.

      You might find www.perimeter.ca interesting. This is Canada's hub for quantum computing research. It's mostly theoretical and they pump out a huge amount of information theory papers. Just go to http://arxiv.org and look up "Raymond LaFlamme".
      • Heh. Come on now, don't you think that NSA's more advanced cryptosystems are based on QPP-hard (or whatever acronym they are using for it these days) problems? While it's true that RSA is vulnerable to factorization, there are problems that are not vulnerable to polynomial time solution by a quantum computer, and there are certainly lots of problems that can be engineered to require ABSURDLY large quantum computers to be useful (hell, NMRQC is never going to get to 128-qubits, let alone past that, and you can indeed quote me on that).
      • Ok, I'll fully admit I'm a complete moron when it comes to cryptography, but I do have a fairly good understanding of how these things work in general.

        The popular assumption is that current cryptographical algorithms could be weakened or compromised by having a working quantum computer and the right algorithm that does something fancy with producing prime numbers.

        Now, my question is, why can't the same quantum compuger and another clever algorithm be used to "up the ante" to the "next order of mangnitude" with a form of encryption which can only be encoded/decoded with a quantum computer?

        And if such a thing could occur, would a "meta-quantum" computer be capable of easily compromising the quantum-only encryption codec?

  • First, here is the abstract [aip.org] for the article.

    Second, it doesn't work, at least not the way they say it does. You can't store 1024 bits in the nuclear magnetic spins of a 19 atom molecule!

    Or more precisely, you can't retrieve that many bits. The spin state of a nucleus can be described by a complex number, but when you do a measurement you only get one bit out. With 19 nuclei you can read out only about 19 bits.

    So how do they make it work? They've got a huge number of molecules there. Each one is loaded with the same data value. Using the redundancy in those molecules, the researchers can read out the 1024 bits. But if they had only a single molecule holding the value in its nuclear spins, as the paper implies, there's no way they could read out 1024 bits. So the density is not as high as they make it sound.
    • Let me explain more clearly, because it seems that some of the moderators didn't understand my comment.

      Think about a photon, which has a linear polarization: up-down, left-right, slantwise, or at whatever angle you want. You can in principle put in an arbitrary amount of information in setting the polarization angle of a photon. You could divide a circle into as many parts as you want, and set the polarization to an angle corresponding to the value you want to send. This is like how they pack 1024 bits into a 19 nuclei molecule.

      Now, the problem is reading the data back out. If you have only one photon in a particular polarization state, you can't determine that state with any accuracy. You can in fact only get one bit of data out of that photon. You can pass it through a polarizer and either it makes it, or it does not. This gives you information about the polarization state but it destroys that state in the process. You can put lots of information into a single photon, but you can't read it back out.

      Now let's imagine that we have lots of photons, in a laser beam for example. We can set them all to the same polarization state. Now we can read the polarization quite exactly, by using large numbers of photons and turning our polarizing detector until we get a peak in the output.

      Even though all the photons are in the same state (like in the NMR molecule experiment), it is because there are large numbers of them that we can read the state back out accurately. We would NOT be able to read back the data from a single photon, and in the same way we would NOT be able to read back the data from a single molecule.

      Hopefully that explains my comment above. A qubit, whether photon polarization or nuclear spin, holds only a limited amount of information, and you can't read more out than it holds. There's no way you can get 1024 bits into 19 nuclei, and no one should try to "spin" the results of this experiment that way.

  • Comment removed (Score:3, Insightful)

    by account_deleted ( 4530225 ) on Monday December 02, 2002 @12:37AM (#4790966)
    Comment removed based on user account deletion
  • That's a fucking big sugar cube.
  • If a single molecule can store an image, what happens if you tell it to store a picture of itself in action? Do you get one of those camcorder-pointed-at-monitor recursive brainfarts?

    Is taking a picture of several of them with a scanning electron microscope, in effect, compression? =)
  • --A picture of your wife contains video of your wedding.

    --Blind people "see" data encoded on their surroundings.

    --Bullets are encoded with their manufacturer, who sold it, and who bought it. Even if it's in fragments.

    --Sentient coatings (sort of). Smart liquids.

    --Something else for Microsoft to claim they invented.

  • ...picture a sugar cube the size of a server? No? OK, I'll go to sleep now.

  • Did that article teach anyone anything? (Score:4, Interesting)

    by blair1q ( 305137 ) on Monday December 02, 2002 @02:03AM (#4791231) Journal
    Blah blah blah

    The quantum states of phosphorus atoms are particularly long-lived, ...and other neobabble.

    The article tells us basically nothing real, except the names of a few people and that they're working on something called "quantum" computing.

    So here's how it should work (off the top of my head):

    An atom or molecule (a collection of particles) has a set of wave-equation solutions. Each of solutions corresponds to a single point in a lattice, whose coordinates are the quantum numbers; or a single value of an n-tuple whose indices are the quantum numbers; or a single member of a set of n-tuples each of which is identified by a unique combination of quantum numbers...however you want to express it. These quantum numbers are inserted into the wave equation and out pops a solution--a wave-function--that does not diverge or otherwise go kaput.

    If the atom, molecule, collection of particles, etc., is in one state (one combination of quantum numbers; one wavefunction), it's just a matter of applying energy in the right way to push it into another state. The quantum numbers move to a new point in the lattice, you change the n-tuple indices, whatever. You really cause the wavefunction to change, and the spatial arrangement available to the particles moving in the system changes. A spherical shell becomes a dumb-bell shape (not really, but it's a simpler visual than what really happens, so go with it).

    Now you have a binary memory system. Most systems have way more than two states, but only a few will be stable (metastable, actually) enough to be useful for computation. But trinary, quaternary, etc. are certainly not out of the question; though the question is a lot easier if you can still use all this software expertise that has binary math running through its veins.

    Quantum calculations are a lot harder to grok than quantum memory. Something has to work so that the state of the memory actuates another part of the system to undergo a change on a quantum level from one stable state (n-tuple value/wavefunction) to another.

    The Heisenberg Uncertainty Principle would get involved, so the family of states you use would have to be pretty special to keep the particles in knowable states. I think that's what the reporter was really getting at when talking about the phosphorus thing.
  • it may not be much longer before Google is running on a server the size of a sugar cube

    Mmmm, sugar...

  • ... a bowl full of these...
  • down at the cafeteria... or maybe it was just a box of sugar cubes?

  • Sugarcube, huh? (Score:2, Interesting)

    by beef3k ( 551086 )
    Well the part of this that actually stores data may be the size of a sugarcube, but if you've ever seen the size of a 400MHz NMR I think you might reconsider your statement. (oh, and leave your wallet at home when you go to work to avoid the NMR's huge magnet going through your credit cards.)
  • If you can't peek at the insides of a quantum computer, what would a debugger look like?

Slashdot Top Deals

Remember, UNIX spelled backwards is XINU. -- Mt.

Close