Slashdot Mirror
A Pair Of Quantum Computing Articles
Will G writes: "3DRage has posted an article entitled "Quantum Computers: How they work and How they will effect us" by Alan Cline. Not only can quantum computers run one billion times faster than typical silicon-based computers, but also theoretically, they can run and consume no energy. That being true, quantum computers could obsolete the silicon chip much as the transistor did the vacuum tube. This paper is intended for the general reader, and explains basic quantum computer features, and the paradoxical effects quantum theory produces in a practical world. This paper discusses how quantum computers originated, the inevitability of their use, and how they differ from classical computers." An interesting nugget to add to this comes from leelaw2000, who writes: "New Scientist have published this little news story about the development of a kind of quantum shielding that might help the development of real quantum computers. Now if they can just get Quake on it ..."
By the way, please don't follow that "q-bits" convention in the New Scientist article. All of the people in the field refer to them as "qubits". Try reading http://arxiv.org/archive/quant-ph (AKA www.lanl.gov). There's no sense in needless term duplication. Thanks.
The "billion times faster" statement was a bit of a stretch. Yeah, it may be able to solve some problems a billion times faster, but comparing the speed of a quantum computer and a conventional computer is a bit tricky (it's not just a constant factor or even close).
You will probably never be able to just drop a quantum CPU into your computer and be off and running, since they're a lot more difficult to work with and not necessarily any better than conventional computers for some pretty common problems. For example, Shor's algorithm for factorization on a quantum computer involves a step that's done on conventional computers, since it's short step that isn't worth coming up with a quantum algorithm for.
Quantum computers are best at problems whcih require searching a large problem space, not just crunching a bit of numbers to get a bunch of values that you'll end up using. A problem like factoring numbers, you search many numbers but only end up using maybe 2 of them. With graphics you actually use all of the values computed (pixel values, etc.), so a quantum computer would not be so good.
If you don't want a faster computer, you're not an imaginative person. Either that, or you can't program.
I can use any ammount of speed I get. Easily.
Fractals are cool, but you can't zoom around any deeper than the very surface at realtime. I'd love to be able to view fractals much faster. I started on an apple 2 that took eight hours to render a shallow julia set, my current P3 800 does that in seconds, my Athlon 900 is even faster.
Then there are my experiments in modelling. I wrote a simple program for viewing the output of an equation on x and y in 3d. When I wrote it in the late 80s it took about a minute to draw a screen. Now, unaccelerated (no 3d card) it runs fast enough for a realtime display.
Give me a more powerful CPU and I'll model more complex equations, or in more detail. Or I'll view deeper fractals, or do one of a million interesting computation problems that are currently out of my reach due to CPU speed.
If the only thing you can think of that requires a fast CPU is Quake, then you'd probably be happy with a PS2 and WebTV.
Besides, when is the gap the widest? When only a few people/agencies have one. If the NSA and a few top universities have computers then the gap is huge because only the richest of the rich can get time on one. But if the technology is developed into a cheap commodity it might still only be directly accesible by the rich, but it'll trickle down eventually.
In a world of ten supercomputers, there's no way a poor african tribesman would *ever* get near one, let alone get to run a job on one. But with the current computer situation he could get a c64 or such fairly easily. I myself learned most of my programming foundation on an Apple 2, the concepts still apply directly. This way the poor have-not could train himself in the new technology and eventually become a have and in the process directly help many have-nots.
The cheaper we can make technology, the more likely it is that someone poor will have access to it. If only universities (and three-letter agencies) ever develop quantum computing then it'll never reach the less fortunate.
People through the word quantum out, and it must mean something great and excellent right? Truth be told, I think this is just another logical progression in technology.
So my side, ho hum... Just like the discovery of new laser types that will supposedly make DVD obsolete last year.
------ 24.5% slashdot pure
This article (the one on 3drage) might not win, but I would bet it would place fairly well in the 'least-content-per-page-to-increase-banner-ads-rev enue' contest.
Seriously, on my screen, I'd say that at least 3/4 of the page is composed of sidebars, banners, ads, table of contents etc. and at 1600x1200 I can see no more than two paragraphs of content: this is totally ridiculous.
Even the NYT switched to multi-page format as a default, but at least their chunks are page-length, and one can easily see the article on a single page via the handy link at the bottom (which I usually use when the article is more than two pages).
Anybody has a link to a similar article in a more reasonable format ? I refuse to give money to a site that cares (much) more about banner revenue than reader comfort.
-- the cake is a lie
Now, when put into light with the idea of a database, this almost sounds like a built-in, real-time transaction log. I hadn't even heard of this effect before in relation to quantum processing, can anyone back it up with any more fact?
This level of reliability and recoverability is amazing (if true)... I seriously think this idea has more potential than the 'no energy used' idea because after all, entropy must increase in a forward-time universe.
--
Gonzo Granzeau
Gonzo Granzeau
"Nothing the god of biomechanics wouldn't let you into heaven for.." -Roy Batty
What you say is most likely true (I am not an expert, and therefore cannot register judgement of fact).
You also raise another good question. Will quantum computers replace the current style of computer? Will we reach a point where the CPU's are so cheap and powerful (and RAM is plentiful) where everything can be done by the CPU and RAM? Will quantum computing even be applicable to applications such as web browsing and gaming?
Without delving too far down into flame, are you suggesting that I put a quantum computer on the 3D card of my 700Mhz Athlon system?
To answer your second point, the article said billion, not million. As the late Carl Sagan would have you know, there is a big difference between a billion and a million...say 4 orders of magnitude.
It certainly seems that you understand the value of using snippets of a conversation to make a point, so I don't understand the reason for your reply.
I think that quantum technology can be used for the purpose that you discuss, it will just come in a completely different form than what you are accustomed to.
For instance, routing could be an application where a quantum computer would be beneficial. Building immense and extremely complicated routing tables would be suited to quantum computing. Having a router CPU that could literally analyze ALL of the routes a packet could take from point A to point B could be very beneficial.
Quantum computing, if successfully introduced to gaming, I believe would eliminate the 3D chipset completely. Currently, we have 3D cards in order to take that processor intensive load off of the CPU. Having a quantum CPU would effectively eliminate the need for a second CPU to munge graphics.
Okay, let's throw out some business jargon and change "paradigms" here. Quantum computers do not have 3D cards, they have no CPU, no RAM, none of that nonesense. Not as I can explain it in 500 words or less, anyhoo.
A quantum computer is literally going to be a new type of computing. Not just as different from a integrated circuit as is a vacuum tube, but as different as an IC is from fire or the wheel. There will be no quantum "chips", no system bus, no SDRAM, no nothing. You will literally have a thing you plug into an interface, probably not even that. Why the hell would any single individual own one of these? If quantum computing is a billion times faster, than one "quantum computer" would take care of the gaming needs of China or India.
Whoa...think of 1 billion people playing Quake all at once...
Disclaimer: I'm a computer science and physics student (combined honours). This means I know more than nothing about this, but not a whole lot more.
Most of the claims in the article are exaggerated. The "consumes no energy" thing is really just theoretical. There are hard minimum limits on how much energy classical computations consume, but no such limits on quantum computations, creating the theoretical possibilty of "free" (from the energy point of view) computations. Of course, you do have to expend energy to read the answer, as someone else pointed out...
The "obviates all encryption" claim has some validity. Quantum computing reduces the complexity of certain computations. For instance, a linear seach that is O(n) on a classical computer becomes O(sqrt[n]) on a Q.C. Likewise, cracking RSA-style public key encryption changes from an exponential-time problem to one that can be solved in sub-exponential time. That's not to say it would be trivial to crack a 4096-bit key, but it would be possible to do so within some non-insane timespan.
As for quantum computing doing infinite computations in a second, this is also a misinterpretation. A slighly better (but still not perfect) way to think of things is that quantum computers do things in a massively parallel way. Maybe you want to think about them as non-deterministic finite automata. That's about the best I can come up with in terms of classical analogies.
I might have mentioned cold fusion, except that I believe that cold fusion is more likely than quantum computing.
Quantum computing is solidly based on widely-accepted theories. More importantly, a working (simple) quantum computer has already been built. With both strong experimental and theoretical support in place, I don't see why you have trouble believing in it. The only question is when it will become practical... As for AI, and natural language processing, QC may just be the technology that enables those things. Read Roger Penrose's "The Emperor's New Mind" for more info...
The tubes are in the AMPS, not the SPEAKERS.
There are tube microphones, pre-amps, phono-stages, amps, etc., but I have yet to see a tube speaker...
--
"It's tough to be bilingual when you get hit in the head."
I apologize; I thought that the difference was pretty implicit in what I wrote. To clarify:
:)
Setting a bit: introducing information into a system.
Clearing a bit: erasing information from a system.
Introducing information to a system has no required energy, but the erasure of information does have a minimum energy.
If a byte has the value 0xFF, then in order to change it to 0x00 I have to erase eight bits of information before I can put in my new eight bits. (Note that most computers do the erase-and-overwrite in one step, but thermodynamically, they're two steps.) In other words, I blow eight bits of information away (which requires energy) and put a new octet in (which does not require energy).
Clearing the eight bits requires a minimum amount of energy given by kT (k = 1.38E-23 J/K, and T = 3.2K, the ambient temp of the universe). That's 4.42E-23 Joules per bit cleared.
Setting the bits? 0 Joules.
Again, this is all in the dimly-remembered past of my college physics. So take it with a grain of salt.
The First Law of Thermodynamics says that entropy never decreases; the Second Law of Thermodynamics says that entropy never remains constant; and the Third Law says that you can't find a process that doesn't involve entropy.
But then again, it's been a long time since my college physics courses.
Tom Swiss | the infamous tms | http://www.infamous.net/
Tom Swiss | the infamous tms | my blog
You cannot wash away blood with blood
What part of "quantum chip be put onto a 3d card" do you not understand? He didn't say put a 3d card into a quantum computer.
If quantum computing is a billion times faster, than one "quantum computer" would take care of the gaming needs of China or India.
And current computers are millions of times faster than the originals. It should then follow that the united states should have exactly 250 computers?
It's 10 PM. Do you know if you're un-American?
Oh, yeah, is that the way whereby when you inspect it it becomes destroyed? Really, does QM itself show any promise for data storage? Aren't you talking about molecular storage? (like in crystals or something). Seems to me QM is really good for processing. I wouldn't trust it to store the state of my cat ;)
It's 10 PM. Do you know if you're un-American?
Yes, that is what the original poster suggested, which I don't see as being that bizarre. You know "computer" doesn't have to mean the entire system including peripherals and monitor. It could mean just a quantum cpu.
To answer your second point, the article said billion, not million.
So? I was impeaching your logic. Current computers are already orders of magnitude larger than the first computers. Does that mean that it is insane to give each person their own computer, instead of sharing the equivalent processing power (~250 computers, given the population of the United States is ~250) amongst all? No. It means that with the new power we'll come up with new things to do.
Putting a quantum cpu on a 3D chip, or imagining that we might actually have new uses for orders of magnitude more processing power just doesn't seem that bizarre to me.
It's 10 PM. Do you know if you're un-American?
This seems to be the same article, pretty much.
--
Of course they would. Every time computer power goes up an order of magnitude, there are always pundits claiming no normal person could ever use that much speed, and they are always quickly proven wrong. If nothing else, think of games: Quake and Unreal Tournament do huge amounts of number-crunching. Until we get to the point where computers can render ray-traced scenes at 60 fps in 36000x24000 pixels (huge flat-panel displays at 300 dpi) there will always be a use for more CPU power.
How to solve most of our problems: 1.Lots of nuclear plants. 2.Cure aging.
Pump anything you want in/out of the edges at 100Megasamples/second (at minimum), do as much hard math/matching as you need, and get the results out.
It would be possible to use "defective" chips as long as the boundary cells were all good, much like we use LCD panels with bad pixels today.
The major hurdle is ween programmers off of the von Neuman architechure, and get them into something that just seems like the biggest gate array in the universe.
--Mike--
No patents were harmed in the creation of this posting
So, basically what I mean is, I don't know what I'm talking about here, but the claim that "they don't consume energy" smells funny based on the little I did learn about quantum computing at one point. Like, even if it's theoretically true, it's deceptive to put it just that way. So, can someone more versed in physics enlighten me and the /. crowd at large?
First paragraph: correct, but obnoxious. There is indeed a set of consequences of quantum theory that includes wave-particle duality, although it is not a fundamental assumption of quantum theory. Second paragraph: correct, the original poster is being silly. But when you say spin can be either up or down and that the state space is 2D, you of course realize that information in a quantum computation can be represented in a superposition state, which can then be manipulated to result in a particular discrete observable given a particular result. Third paragraph: the original poster is talking out of his ass, true. The "speedup" is the result of the fact that a QC algorithm can effectively run a large number of "computations" in parallel, in Hilbert space, resulting an answer in far fewer steps. Of course, only some problems are "quantum computationally feasible" in the sense of taking far fewer steps to solve in a QC process than in a conventional algorithm (Schnor, Grover, etc. are a couple of algorithms that would be particularly useful and nifty if we had a big enough QC to solve them in practical situations). Similar in nature to the various P* complete etc. ways of describing problems that are polynomial time under parallel processing, etc.
Slashdot already has an article on the 'shielding' method. Search for 'decoherence free subspaces'.
---- SIGFPE
Great, now audiophiles will insist on buying transistor-based speakers, because "they sound better, really!"
"The question of whether a computer can think is no more interesting than that of whether a submarine can swim" -EWD
I know there have been alot of errors mentioned but I didn't see this one yet. In 20 years, by Moore's law, processors won't be just 40 times faster (if that's what was implied by the 40Ghz statement) they will be more like 5,160 times faster. Because speed (or at least transistors)will have doubled like 13.333 times. I am not sure if I did the math right but only 40Ghz? We should be there in about 6 1/2 years following Moore's law. I will finally be able to run Quake III at my desired 50,000 frames/second. I can tell the difference I swear!!
This Wiki Feeds You TV and Anime - vidwiki.org
One million = 1,000,000 = 1 x 10^6
One billion = 1,000,000,000 = 1 x 10^9
9 - 6 = 3
Where the hell did you get 4 from?? Figured the factor of 1,000 had four digits in it? Try and get your math right the next time you're being condenscending about numbers.
"Mind, as manifested by the capacity to make choices, is to some extent present in every electron." -Freeman Dyson
Um, the transistor didn't wipe out the vacuum tube. Trust me, tube-based guitar amplifiers sound a million times better than anything base on transistors. And they're still being made.
There's no such thing as an obsolete technology, merely one that's got a smaller application base than it used to have.
Furthermore, with this billion-fold speed increase, what kind of peripherals are you going to have?
----------------------------------------
Yo soy El Fontosaurus Grande!
blog |
Rather than blindly believing it one should remember what came of the big hype surrounding: AI -"we're only a few years away ©1967", COBOL -"the programming language for managers and non-techies", 4GL -"Natural Language Processing", The "paperless office", National missile defense, 100% portable java code, MULTICS, the "New Economy", the "Information Super Highway", and just about every CASE tool ever.
I might have mentioned cold fusion, except that I believe that cold fusion is more likely than quantum computing.
"Quantum Computers: How they work and How they will effect us"
Although quantum mechanics leads to very strange and wonderful things I doubt anything they do will effect us. They might affect us. Next story, please! I don't read items that so blatantly butcher the language.
While setting a bit may not require any energy expenditure, reading it will, thus any computation based on a previously set bit will consume energy. Now, if you can prove the ability to set, read, and clear a bit with no energy being expended, you're either the harbinger of a new age of computing and life as we know it, or just insane ;-)
Think outside the... Hey, where'd the friggin' box go?
If you can show me how in all concievability that cat can be both dead and alive, then quantum theory is possible - otherwise it just won't work.
This is the "Schroedinger's Cat" example of quantum mechanics, filtered through a particular "Many Worlds" interpretation of quantum mechanics...but a cat is not a quantum system, and the interpretation you choose to apply to describe your philosophical position does not affect the physical system one bit. The cat is an analogy, if you will, not to be taken literally (although that is one other philosophical interpretation of the theory). It is an analogy for the way that quantum states "superimpose" on other quantum states: an electron when observed has either spin up or down, but while it is evolving unobserved, it really CAN BE in a state which is both up and down at the same time....and it "picks" which state to be in when observed in certain percentages based on the evolution of the state (again, this description is colored by a particular interpretation...if you want, rather than "picking a state" think "choosing a universe where the observation is made"). The technical details can be found in any undergraduate quantum mechanics textbook.
Quantum mechanics is the realization, at small distance scales (atomic and smaller), systems have to be described in terms of different dynamics than they do at the macroscopic level. There is nothing strange about this...physics at larger scales is always a limiting case of the physics at smaller scales. And quantum mechanics itself is extremely well tested and understood (all of modern chemistry, semiconductor development, biochemistry, superconductors, particle physics, etc. are based on quantum theory). Quantum behavior is not only conceivable and possible, but it appears from experiments that it IS the way reality is constructed; it is far from busted, and we are a much happier world for discovering it.
A one-time pad is not encryption, it is a method of verification. As for the encryption thing: all forms of encryption (so far as I know) can be brute-forced. With the supposedly unlimited power of a quantum computer, you could brute-force anything instantly.
CAP THAT KARMA!
Moderators: -1, nested, oldest first!
SIG: HUP
Now here's the zinger; in one universe, the cat is alive, and in another, the cat is dead. How? The cat is either dead or alive - there aren't 2 cats. Just because you can't tell if the cat isn't there until you can see it (another thing about quantum theory - if you can't observe it, it is in all states simultaneously) doesn't mean you have a cat that is both dead and alive.
If you can show me how in all concievability that cat can be both dead and alive, then quantum theory is possible - otherwise it just won't work. One busted theory, and a dissapointed world without its computer.
One more thing: quantum computing, if it exists/work, would effectively nullify encryption. Ouch.
CAP THAT KARMA!
Moderators: -1, nested, oldest first!
SIG: HUP
I have read that the applications of quantum tech are much more widespread than most people relize. For example, it has been proven that one can measure the width of a human hair using a laser with quantum enhansments without the laser touching the hair whatsoever. They have also successfully 'teleported' a single atom instantly from one place to another (about 100 feet from the origin).
There are many more possibilities in the future of quantum technologies, and I think quantum computing is probably going to be the least of these achievements - even if it may be the first.
A good read, however fiction, is Micheal Cricton's 'Timeline', which covers some facts regarding quantum tech at this point, and also goes into some ideas of where things could progress to.
.
Damian Conway threw together a brilliant application for this new breed of computers. QSP
Imagine not having to wait Log N for anything!
Dancin Santa
... those articles blew my mind. But one has to consider this: how practical is it to be salivating when this sort of technology is decades away? And while it does sound nice and eco-friendly, I think that there's potential to widen the "techonology gap" between the have and the have-nots even further. This is, of course, assuming that such powerful computers have applications beyond number-crunching and the military.
--M.
Ok so the first thing every one is talking about is this "Complete Reverseable" computation. Well thats wrong and taken out of context (trust me Im very adept at this theory and work with it on a daily basis) The nature of quantum gates, which comprise a quantum computer, are not reversable! though there are a few quantum alg that can be reversed it doesent me all can.
Secound - while a quantum computer may be able to do a ton of caculations at the same time we will never know the answers with the current theory of QM and here is why. Think of a Quantum Bit, a QuBit (and we are not building Ark's here), as a unit vector in 3d space. ITs possible for this vector to point in any direction orginating at the orgin, thus creating a "ball" in space. Now when 2 Qubits are put into the system (a Q-gate) u get 2 out puts (one from the first out put = the first imput un-altered, the secound output an altered form of the secound input). So how do we know what we did, well you observe the system, take a measuremnt. To take a measurement in QM you can only measure orthogional states, ie two possible out comes in a QuBit system, by doing so you force the "ball" (which is all possible outcomes) into one of two vectors thus reducing your infinte caculation. And after you take that measurement it doesent mean that the QuBit u measured will give you the same answer if you measure it again!
well I think thats enough for your to think on.
I understand it differently. AFAIK, Landauer showed that enmergy must be spent to erase information, not to clear a bit. You are erasing information if you use a gate with more input wires than it has output wires. For example, a clasical NOT gate has one input, one output, and no info is erased because you can always tell what input caused a given output; it's reversible. But a classical AND gate could cause a 0 output in three possible ways (00, 01, 10), and you can't tell which; it's irreversible, because you've erased information. Read http://www.qubit.org/intros/compSteane/qcintro.htm l for some more info.
Also, someone should note that the energy savings from reversible computation are real but very, very tiny. Chips would have to get 1 million times more efficient than they are now for the energy costs of (current) irreversibility to manifest themselves. And if you expect a quantum computer to operate without tons of expensive, high-powered supporting equipment around it (NMR machines, optical pumps, liquid helium-cooled ion traps), you'd better add a couple more decades onto your time estimate.
Zero-energy computation isn't anything new, in theory; we've known what must be done to achieve zero-energy computation for a long time. We just haven't quite been able to figure out how to do it.
:)
In principle, setting a bit requires no expenditure of energy; it's clearing the bits that requires an energy expenditure. So, provided you can figure out a memory design which permits that bits be set and never cleared, you can achieve zero-energy computation.
Note that I'm using "requires" in a very narrow context here. Setting a bit requires no expenditure of energy, but all the computers we have right now expend energy to set bits. That's a limitation of design, not any thermodynamic limitation we're currently aware of.
All of this comes to you courtesy of some long-ago college courses on the physics of computation. I may be misremembering quite a bit.
In real life, we don't have systems accurate enough to deliver one photon to one atom (or nucleus). Instead, we play the odds and bombard the q-bits with a very large number of photons until it is in the proper state. All the other photons are lost.
Technically, they could capture all the photons emitted by the q-bits and return them into the system at a later time. But I don't think that will happening any time in my lifetime!
-----------------
In other words, if there is no thermal dephasing, you can operate with no energy consumption so long as you never look at the output, but there is a rigorous minimum value of energy that it costs to look at the output. This limit is set by basic thermodynamics and is inescapable.
In practical terms, cooling the computer to feasible cryogenic temperatures will consume lots of energy even when the qbits do not. Moreover, the fact that you will run the computer at finite temperature makes it necessary to apply error-correcting codes to compensate for thermal dephasing. Error-correcting steps are irreversible and thus consume energy during the calculations.
what I was always curious about was whether quantum computing could be put into non cpu environments, still processing, but not as general purpose. For example, could a quantum chip be put onto a 3d card, and make it work a million times faster? Or could it be put to use in network switches with regard to 100% optical switches pushing us into 1TBit networking?
---
Video meliora proboque deteriora sequor - Ovidius
for Quantum Computing Purposes...
Skip this if you've had even Physics 101.
First of all, Quantum Theory as we know it has been devised over the last century. I could name a lot of famous scientists names like Heisenberg, Schroedinger, and Fermi, but you don't care so I won't.
The meat and potatoes of quantum theory is this: All particles, no matter what the size, act as both a wave and a particle. According to research, either the location *or* the mass of a particle may be known at any time.
Also, as we all know, wave interfere with eachother. If the crests of two waves overlap, they grow. This is referred to as 'Constructive' interference. 'Destructive' interference happens when a crest of one wave overlaps the trough of another wave. This gives rise to many observable phenomena, such as diffraction lines you can see when you stare at a bright light through your eyelashes. This is what causes 'ice rings' around bright lights in cold weather and the occasional 'moon ring'. It's also why you have to have your surround sound speakers positioned just so, so that they don't interfere with eachother.
Early experiments where researchers shot electrons through tiny holes in a lead sheild and onto film created similiar diffraction patterns, because, since electrons are indeed particles, they are also waves. The real shock comes when you only shoot one electron (or other particle) at a time through a sheild to create a pattern on film. Even though there was nothing for the particles to interfere with when shot one at a time, they *still* created a diffraction pattern.
This gives rise to the thought that particles that store their energy in 'quanta' and are small enough not to interact instantly with their environment, exist in multiple probability states. The electrons that created the diffraction pattern were interfering with the possibility that they existed elsewhere in the experiment.
In quantum computing, this is useful because electrons can be made to do different things at the same time, such as be in different places or aborb and release different amounts of energy. They can also simply stop existing at one place and start existing at another. They can also rock back and forth through time. Quantum computing, for the uninitiated, relies on harnessing these seemingly paradoxical phenomena. If the theories are all correct, this means that information storage will simply become infinite because there are an infinite number of states that any electron can occupy. Energy required to run a quantum process will be very little or zero, due to basic laws of thermodynamics and quantum physics. Speed of computations will be astronomical because quantum interactions take place on the pico-scale.
Quite a nifty thing...
Schroedinger's Cat says: It is not the world that must bend, but your mind. You must realize taht there is no mouse.
The next Slashdot story will be ready soon, but subscribers can beat the rush and slashdot the links early!
I suggest any reader interested in getting a good introduction to QC to take a look at a presentation given by Rob Pike at USENIX, available in MP3 audio here. It talks about the motivations on using information quantum mechanicaly (intrinsic parallelism, we are running out of atoms, etc); some historic aspects (Feynman's question: Can a computer simulate a QM system?); the approximations that you eliminate when you use QM computing devices (bits are not independent, but entangled); some algorithms (factoring, searching), etc. Not only nice, but funny too. Don't forget to get the slides also.
Just notice that there are two different aspects when we talk about QM systems, which most of the time are treated together: First, there is the QM way of representing information, which is to some point a reality now (on modern, high density Hard-Disk, for instance), the other is QM computers, which is something for way in to the future.
The simple answer is "possibly"
For example, it is possible that quantum computing can greatly increase 3D rendering. Basically, the main problem in ray tracing is finding the correct number of solutions that will lead a light ray to the point the eye is looking at. There are stochastic methods, like Metropolis, that greatly speed up the process of determining these solutions, but like most stocastic methods when compared to quantum methods, they are unreliable and slow (although when compared to deterministic methods, they are unreliable and fast). In a quantum 3D chip, you can theoretically easily find all of the solutions in a very short time, and thus determine the light levels for the point. This would in effect give you a perfect ray trace in a few cycles/point.
And even then, given enough qbits, you could be running those raytracing calculations on all of the points, oversampled by 256 to give a nice antialias.
But this is all in theory, because there are severe limitations on the logic that one can do with a quantum computers today. While the above could be modeled, I don't think we'll know for a while if it can be.
-no broken link