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Tiny Holes Advance Quantum Computing 255
Nick writes "Worldwide, scientists are racing to develop computers that exploit the quantum mechanical properties of atoms - quantum computers. One strategy for making them involves packaging individual atoms on a chip so that laser beams can read quantum data. Scientists at Ohio State University have taken a step toward the development of quantum computers by making tiny holes that contain nothing at all. The holes - dark spots in an egg carton-shaped surface of laser light - could one day cradle atoms for quantum computing."
Great principle (Score:5, Funny)
Re:Great principle (Score:2, Funny)
Good one.
Re:Great principle (Score:2)
Re:Great principle (Score:2, Informative)
Re:Great principle (Score:3, Insightful)
Re:Great principle (Score:3, Funny)
Re:Great principle (Score:5, Informative)
And now you know... the rest of the story.
Re:Great principle (Score:2, Informative)
Re:Great principle (Score:2)
Re:Great principle (Score:5, Informative)
Indeed, talking about quantum computers as an improvment on silicon computers is like talking about jumbo jets as an improvement over cars. Ie not an improvment at all, unless you have something very specific to do (factor a large integer or cross an ocean). And you need the simpler alternative to use the more advanced one (car to get to the airport, regular computer to feed and extract data for quantum computing).
Comment removed (Score:4, Interesting)
Re:Great principle (Score:5, Interesting)
Re:Great principle (Score:4, Interesting)
So, what kind of scale are we talking about here? To simulate, say, a million-transistor CPU and a megabyte of RAM, how many qubits would you need? About as many as you need transistors, or radically less?
If the answer is millions, then I think my comparison to a jumbo jet is valid, as we're probably about as far from a quantum computer simulating even a 4004 with hundreds of bytes of RAM, than we're from ubiquitous flying cars replacing jumbos
Re:Great principle (Score:4, Interesting)
Re:Great principle (Score:2, Informative)
Make that log2(N) qbits. 2^N would be a bit excessive (to factor 15 they'd need 32000 qbits. They used 7 of them)
Re:Great principle (Score:2)
I thought it was around 2N qbits to factor an N-bit number.
Re:Great principle (Score:3, Informative)
From TFA: "In principle, quantum computers would need only 10,000 qubits to outperform today's state-of-the-art computers with billions and billions of regular bits," Lafyatis said.
Re:Great principle (Score:2)
Yes, but as far as I understand, that *only* applies to problems you can solve with 10k qubits, and that's quite a limited set.
It is my understanding that, for example, doing a filtering operation on a 2 hour film consisting of 5 megapixel images, 10k qubits would not help you much. AFAIK 1 qubit is still just one "serial" b
RTFContext (Score:2)
Sure, for specific classes of problems that quantum computers are really really good at. But the whole discussion in this thread was about quantum computers simulating classical computers doing their everyday, mundane, classical computer things.
The quote shines no light on the actual question: How powerful of a quantum compute
Factoring is NOT known to be NP-complete (Score:5, Informative)
You had better get that right in your undergrad thesis
Re:Factoring is NOT known to be NP-complete (Score:3, Interesting)
Re:Factoring is NOT known to be NP-complete (Score:3, Interesting)
You're misusing that first word.
A "simulation" is a testable model of something, usually created for a specific kind of testing, that specifically is NOT the thing itself. By way of example, consider "simulating" adding numbers on a computer chip. Most of the time you wouldn't bother doing it, because it'
Re:Actually PRIMES is in P (Score:2)
-1, Insensitive (Score:2, Funny)
Didn't they try that back in 2001?
Re:Great principle (Score:5, Informative)
If by "no problems" you mean "severe and most likely insurmountable quantum coherence issues". Any quantum computer big enough to simulate a modern sized classical computer will contain so many qubits as to have problems with interference from the outside world. IIRC the problem of quantum coherence is roughly exponential in the number of qubits in a system (one of the reason we don't have 1000 qubit computers sitting around). Just having enough qubits to remember my RAM would get pretty ridiculous.
The truth is that quantum computers, in the forseeable future, will likely be an orthogonal type of computing system to classical computers - a coprocessor used for certain problems with small memory requirements but large search spaces. Many of our most important computations lie in this regime, but I doubt quantum computers will outperform classical computers on most ordinary stuff (i.e. word processing, running a webserver, handling large databases) due to its seriality and memory intensive nature. (Insert quote like "640 k ought to be enough for anybody" here)
Also, the fact that quantum computers can factor large integers efficiently necessarily implies that they can do other NP-complete problems efficiently, such as the traveling salesman problem.
It implies no such thing [wikipedia.org]. Traveling salesman problem is NP-complete [wikipedia.org], and while we have no solid proof that a quantum computer cannot solve an NP-complete problem in polynomial time, Shor's algorithm is also in no way any kind of proof, as integer factorization is merely NP [wikipedia.org], not fully NP-complete as you claimed.
Yes, IAWAUGTOQC (I am writing an undergrad thesis on quantum computation).
Yes, I do have a degree in physics. You may wish to check said thesis in light of errors explained above.
Damn Butterflies. (Score:3, Funny)
Re:Great principle (Score:5, Informative)
And I'm doing a Ph.D in physics on quantum computing. Sorry to be a prick about it, but you were a bit rough on the undergrad who posted above, and what goes around comes around. As long as that guy isn't doing his research on slashdot, he'll probably be OK..
If by "no problems" you mean "severe and most likely insurmountable quantum coherence issues". Any quantum computer big enough to simulate a modern sized classical computer will contain so many qubits as to have problems with interference from the outside world. IIRC the problem of quantum coherence is roughly exponential in the number of qubits in a system
No, the problem is not exponential in nature. It has been shown that if the error rates for storage, gates, etc. can be brought below certain thresholds (typically 10^-3 to 10^-6), then arbitrarily long computations can be performed. There are many papers on the subject, but here is one [arxiv.org].
The only way in which decoherence could pose an insurmountable problem is if there is fundamentally new physics that plays a role in the regime between "quantum" and "classical". Nobel Laureate Tony Leggett has talked (in a recent issue of Science, and at the 2005 Gordon Research Conference) about how we might find such new laws of physics if they exist, or otherwise rule out their existence.
It implies no such thing.
You are correct. In the early days of the field, I think there was a little bit of confusion about whether quantum computers could do NP-complete, but it has long since been sorted out.
I recently attended a talk by Ike Chuang about general issues in the field. Chuang feels that quantum simulation and quantum communication will be the important applications, although he emphasized communication. I think quantum simulation is way, WAY underappreciated. Not only is it going to revolutionize protein folding, drug design, and other biomed applications, I have a hunch it may prove to be a prerequisite for advanced nanotech.
The article is not particularly good. The supposed problems that optical lattices will have in addressing qubits in the interior of a 3-D lattice are "solved" by using what is essentially a 2-D lattice on a chip. The same can easily be done with optical lattices.
Of course, addressing atoms inside a lattice of moderate size can be done using a high numerical aperature lens to focus an addressing beam onto a single atom. The addressing beam produces an AC Stark Shift of the appropriate hyperfine sublevels of the atom (in the case of Cesium-133 qubits, it shifts each of the mF sublevels of the F=3 and F=4 states), with the exact shift being different for different sublevels. This allows transitions in that particular atom to be driven by a microwave pulse which is detuned from all the other atoms in the lattice. Just how well can we address one atom while not disturbing atoms in adjacent planes? I'll know in a week or two. I'm currently simulating one and two qubit gates in this exact scheme. The actual experiment is also under construction, at Penn State.
Anyone interested in a distributed computing project to develop quantum computers? I could use help from developers, and later, also regular user input.
Re:Great principle (Score:3, Informative)
Re:Great principle (Score:2, Interesting)
Re:Great principle (Score:2)
But they might if they figure out a way to make quantum breast implants...
Re:Great principle (Score:2, Insightful)
Re:Great principle (Score:2)
Re:Great principle (Score:2)
Re:Great principle (Score:3, Funny)
*gets 2,124,972, 421 as an answer*
*enters 1 + 1 again*
*gets 0.0012 as an answer*
Re:Great principle (Score:3, Funny)
*gets 2,124,972, 421 as an answer*
*enters 1 + 1 again*
*gets 0.0012 as an answer*
So the Pentium was a quantum computer?
Re:Great principle (Score:2)
*enters 1 + 1 into the built-in calculator*
*gets 2 as an answer*
*enters 1 + 1 into the built-in calculator*
*gets 2 as an answer*
*enters 1 + 1 into the built-in calculator*
*gets 2,124,972, 421 as an answer*
*enters 1 + 1 into the built-in calculator*
*gets 2 as an answer*
hmm. the answer's probably 2!
Re:Great principle - Funny? (Score:2)
Baby Steps (Score:2)
I realize all new technology comes in baby steps, but its somehow disappointing to hear that they "have taken a step toward the development of quantum computers" by making one little piece.
With all the talk of quantum computers on
Definitions? (Score:5, Funny)
Well, yes, that rather is the definition of "hole," isn't it? Having nothing in them is what distinguishes them from the rest of the surroundings.
Re:Definitions? (Score:3, Insightful)
Re:Definitions? (Score:2)
Re:Definitions? (Score:2)
No, there could be tiny gophers (Score:2)
Then they would be tiny holes that contain gohphers, you see?
Fore!
Re:Definitions? (Score:3, Insightful)
Mind Boggling (Score:5, Funny)
So these boffins have developed "nothing", but one day, in the far future, this nothing could be filled with something important.
Wow. What an age we live in.
obligatory Simpsons quote: (Score:5, Funny)
They're speed holes, they make the computer go faster....
Best part of quantum computing (Score:2, Funny)
"Why would anyone need that much power? I remember 9 years ago when we only had 10 qubits [wikipedia.org] to work with! Quantum programmers sure are spoiled and lazy today."
Re:Best part of quantum computing (Score:2)
How many were there? (Score:2, Funny)
Re:How many were there? (Score:4, Funny)
Four thousand.
I was never quite clear on how the holes from Blackburn, Lancs. could possibly fill the Albert Hall. I mean, they're holes - defined as being something not there. How can they fill anything?
Then I discovered marijuana, and understood :-)
Magic Red Smoke (Score:3, Funny)
Quantum computers will use red smoke (the Rubium cloud). Will we call the hobbiests that push the limits of these machines Quark shakers?
wait a minute (Score:2)
If Schroedinger is anything to go by. . . (Score:2, Funny)
. . . won't quantum computers mean an end to binary?
In the old days, a cat in a box was either alive or dead - one or zero, you might say. Nice and easy.
But when it gets quantum? How the hell is a simple machine going to cope when it asks "Is it one or zero?" and gets told "Both"
"We've had to replace 'if' and 'and' with 'maybe' and 'probably'. And 'not' has become obsolete."
Re:If Schroedinger is anything to go by. . . (Score:5, Insightful)
Going back to the same metaphor you began to use, the principle that the Schroedinger's Cat Experiment is suppposed to illustrate is not the concept of superposition (that the cat is both alive and dead whilst in its quantum state in the box) but the concept of decoherence of the quantum state under observation.
It's currently a postulate of quantum mechanics (i.e. everyone observes this phenomenon but nobody can explain it) that observation of a quantum state in a superposition (say, a "qubit" -- perhaps an electron spinning up for 0 and down for 1) will have one of the two values, with certain probability. Once read, the state loses that superposition and remains in the observed state (Recall: in the SCE, the cat stays alive or dead once you open the box).
If you don't want to measure your qubits, and thus maintain their superpositions, entanglements, etc., that's fine ... of course, you can't get any information out of them. If you've properly designed your quantum machine, you may have a guess as to what the possible states are; you may even know the probability of each one.
As soon as you ask to see a qubit, however, it becomes a classical bit and stays one. That's the downside to all this quantum stuff.
Quantum computers also do not mean an end to binary -- currently, since humans have, and are trained to use, primarily classical faculties, quantum research is aimed at extending classical computation. So we typically discuss a "qubit" which may be 0, 1, or some combination thereof (specifically residing in the field C x C). But, if we ever want to interface a quantum computer with a classical instrument (for example, some sort of I/O device, or a classical computer, or a human) then we will unavoidably devolve back to binary.
For more information, I recommend Nielsen & Chuang's book on Quantum Computation and Quantum Information (I think; I don't have it in front of me right now).
Disclaimer: I am not a quantum mechanic. I am, however, an junior finishing up my degrees in mathematics and computer science so that I can go on in a year to work on a PhD in quantum computation. --0x4a6d74
Re:If Schroedinger is anything to go by. . . (Score:4, Informative)
Nielson and Chuang's book is neat (I have it sitting on my floor 3 feet from me ATM). It's mainly written for the physicist to learn quantum circuits and algorithms. It takes a year to read, but by the time you are done, you should be able to read and understand most of the papers in the field.
A much lighter book on the subject is "Explortions in Quantum Computing" by Williams and Clearwater. It gives a basic overview without much assumed knowledge.
Also "Problems & Solutions in Quantum Computing & Quantum Information" by Willi-Hans Steeb and Yorick Hardy has alot of fun problems in it. It's the kind of book thats good to read on a bus, or an airplane.
Re:If Schroedinger is anything to go by. . . (Score:2)
Re:If Schroedinger is anything to go by. . . (Score:2)
why does it need an "observer"? what exactly is an "observer"? how do we know this is the case? seems to me that the cat is either dead or alive how can it be both? you open the box and find the cat dead or alive, so how do you know it was in some other state before "observing" it? this all seems counterintuitive to normal logic so why should i belie
Re:If Schroedinger is anything to go by. . . (Score:4, Informative)
While I'm not sure there is an explanation that makes intuitive sense, it does appear to be the way the universe works at small scales.
Schroedinger's thought experiment was intended to illustrate the weirdness of the issue by tying the state of a macroscopic object (a cat) to a quantum state (the decay/not decay of the particle), mainly. It's not a realistic experiment because you couldn't isolate the macroscopic contents of the box from the outside world sufficiently (and besides, it's cruel).
But, real experiments do demonstrate that quantum stuff consistently behaves in really bizzare and counterintuitive it-is-but-it-isn't ways.
One famous example is the oft-repeated "double slit" experiment (hopefully I won't mangle the summary too much).
You remember light-as-waves? If you take a coherent light source (i.e. a laser) and shine it onto a screen through a mask with two small parallel slits in it, you will see a pattern on the screen resulting from the two interfering wavefronts.
That's simple enough. But light is also particles (photons). You can put a filter between the lazer and the mask that only allows one photon at a time to dribble through. Now you have individual photons going through the mask, and you see individual spots as they hit the screen. Intuitive enough.
But it starts to get weird. If you measure the brightness of those spots, though, they still follow the brightness of the interference pattern. That would suggest that the photon is going through both slits at once and somehow interfering with itself. Hmm, that's not very intuitive.
But, okay. We can test that by using detectors at the slits to note the photons as they go by. Hmm. No, each photon is only going through one slit or the other, not both at once. So why are we getting the interference pattern? Wait, where did the interference pattern go?
Huh. We stop observing which slit the photon is going through, and the interference pattern comes back (i.e. it effectively went through both slots). We start observing again, and it starts "picking" one or the other slot again...
Basically it looks as if, to employ a gross anthoropomorphism, on quantum scales the universe is "lazy", and only commits to a specific choice if it has to (because somebody is watching). No, that's not intuitive, and no, we have no clue how this happens exactly (although we're getting better at describing it and exploiting it for practical purposes like primitive quantum computers), but that's what happens.
Physicists are wrestling with that one. We don't really know. A person directly observing the quality being tested (directly or via instrumentation) seems to be sufficient, but not necessary.
That's one of the downsides of the "Copenhagen Interpretation", which is the most common interpretation of these phenomena -- that an observer observing "forces" the universe to make a "choice" (the grossly anthropomorphic word choice is mine though -- the actual way of putting it is that the act of observation "collapses the wave function").
There are other interpretations, too, that don't require a privileged position of "observer", but they have other very awkward quirks.
Certainly you shouldn't accept it just because someone says so, or because a few experiments suggest it might be true. In this case, though, the experiments have been repeated too many times by too many different people for the weird results to be the result of experimental error though, and also experiments designed to disprove these behaviors have fai
Re:If Schroedinger is anything to go by. . . (Score:2)
Re:If Schroedinger is anything to go by. . . (Score:3, Insightful)
"spin" is just a label we've adopted for an abstract property of particles for which we don't have a good name otherwise. It becomes more obvious in e.g. quantum chromodynamics, where we use labels like "color" to describe particles.
Sadly, it's all too easy to mistake the map for the territory here.
In physics, even the notion of particles is a metaphor f
Re:If Schroedinger is anything to go by. . . (Score:2)
Re:If Schroedinger is anything to go by. . . (Score:2)
Heh, seriously. I guess it's what we're used to though.
Re:If Schroedinger is anything to go by. . . (Score:2)
Re:If Schroedinger is anything to go by. . . (Score:2)
But I'd be careful making an alchemy/astrology comparison... A key difference between alchemy/astrology and chemistry/astronomy is that the former are occult systems where metaphors are evaluated subjectively, and the latter are
Re:If Schroedinger is anything to go by. . . (Score:2)
Although I don't think it's conscious, lot of people really do end up trying to treat scientific issues in religious terms. Witness BOTH sides of the creationism/evolution/etc flamefests.
Re:If Schroedinger is anything to go by. . . (Score:2)
Unless it's been reported alive or dead on Fark. ("The cat, once thought dead, then alive again, then dead, is actually, alive... for now. Quantum physics make my head asplode.")
Re:If Schroedinger is anything to go by. . . (Score:5, Insightful)
Quantum computing, as I understand it (IANAQCS/P) works off the principal of super position; the ability for a bit to represent multiple bits, simply by the spin of the electron, or some other random thing that I wouldn't know how to explain.
If you defined a zero as a square, and a one as a circle, then a quantum bit would be a cylinder; from one perspective you see the square, yet turn it on its side and you see its other property. But since you have other posibilities (cubes and spheres in this system), the "third dimension" persay has to be explicitly asked for by the requesting computer.
So it's able to perform a massive amount of calculations based on a little bit of data, and store it as one neat little package at the end (either the cube, the sphere, or the cylinder). When someone comes along to ask, "was the answer a zero or a one" then, the only way to answer is "depends on the perspective".
Original News Release (Score:3, Informative)
Milalwi
Re:Original News Release (Score:2)
Re:Original News Release (Score:2)
Muck Fichigan - GO BUCKEYES!
Re:Original News Release (Score:2)
I just ordered my Texas ticket through a friend's student ticket. I'll be living in Austin starting in July, but you can rest assured that i'll be talkin plenty of friendly smack for that game!
Re:Original News Release (Score:2)
Tressel knows this, and with the secondary Ohio State has (not to mention the offense) Texas is toast. Plus, Mack Brown is as big of a moron as Lloyd Carr is (hooray Lloyd - 1-3 vs. Tressel).
I live in Texas - these fans down here sure are proud of the vastly overrated Big 12.
Someone please clarify (Score:2, Interesting)
1. What is the working principle behind this (mechanism of trapping) ?
2. Are these experiments performed at room temp
Re:Someone please clarify (Score:2)
They usually trap ions which are charged, and so can be trapped with an electro-magnetic field. A slight subtelty is that you need an oscillating electric-magnetic field which is exactly what the laser provides.
2. Are these experiments performed at room temperature ?
Hell no, unless you have a holiday house on Triton. They are cooled to almost absolute zero, because otherwise the ions are just moving too quickly to be trapped.
3. H
Related article (Score:2, Interesting)
When shall we get pet dark holes?
Imagine cleaning the house with one of these around!
In related news... (Score:2, Funny)
In related news, Ohio State University has recieved research funding from the NSA to perform Ear Exams on all members of Congress twice a year...
The Law. (Score:3, Interesting)
Re:The Law. (Score:2, Interesting)
*cough*fusionpower*cough* The eternally "just around the corner" technology.
Hey, I tease mankind. :)
Nanomechanical quantum computing (Score:2)
See the Animation (.mov and .wmv) (Score:2, Interesting)
http://researchnews.osu.edu/archive/eggcarton.htm [osu.edu]
Re:Just in time for Lonhorn!!! (Score:5, Funny)
If you get a quantum 3D-accelerated graphicscard.
Re:Just in time for Lonhorn!!! (Score:3, Funny)
Re:Just in time for Lonhorn!!! (Score:2, Funny)
Re:Just in time for Lonhorn!!! (Score:2)
'According to kinetic theory there would be no movement of individual particles at absolute zero, and thus any material at this temperature would be solid. This has been proven false and it's better to describe absolute zero as the temperature where no further energy may be extracted'.
Particle motion wouldn't cease because then it would be possible to know the position and velocity at the same time - impossible with quantum mechanics.
Re:Wow (Score:4, Interesting)
Re:Wow (Score:5, Funny)
Simple. They'll just repolarize the quantum invariance field and then bombard it with a tachyon pulse. This creates a standing wave of Heisenberg Flux, which is the only way to be certain the hole is empty.
Re:Wow (Score:2)
Re:Wow (Score:2)
Just make sure all the cracks are covered by duct tape - lots and lots of it.
Re:Wow (Score:2)
Re:Wow (Score:5, Interesting)
There are a lot of extremely odd quantum effects which aren't physically possible, in any classical or comprehensible universe, however do happen. For instance, it's possible to create a negative temperature. Not negative, as in minus 22 farenheit, but negative, as in below absolute zero!
This happens when you rapidly invert the polarity of a magnetic field in which is contained a bose-einstein condensate - in the time that it takes for the condensate to re-align it's spin, it has a rapid change from a negative temperature to a positive temperature once more. The energy of a negative temperature is, actually, greater than that of an infinite positive temperature!
Anyway, enough quantum rambling. If you don't believe me, look here [google.com].
Re:I am Ready (Score:2)
Re:I am Ready (Score:2)
Time Cube [timecube.com]
(sorry, had to do it!)
Re:tiny chips, tiny problems (Score:2, Informative)
One of the key to making things at nanoscale is to have fault and defect tolerance. With billions of elements in the system, you are bound to get manufacturing defects as well as many run-time defects. Even in modern DRAMs
Re:tiny chips, tiny problems (Score:5, Insightful)
No, but first, our scientists have to clean their teeth, then our scientists will be asleep for the next eight hours. Once our scientists have got up in the morning, they'll have a bowl of cheerios and then read the paper for a bit. Then maybe they can tackle the Hubble telescope problem (although the fact that all n million of them are trying to write on the blackboard at the same time does mean they won't make much progress. And the biologists have to sit around twiddling their thumbs because there's not much they can do to help). After Hubble, there's some promising work on cancer they need to finish up, before they can get on with a bit of geology.
Hopefully, someday soon, our scientists will realise that they can get much more done if they allow small groups of themselves to concentrate on different things, so they can make progress in different fields at the same time. In the mean time, though, you're right. They're all wasting their time on this pointless quantum computing nonsense.
Re:tiny chips, tiny problems (Score:2)
Re:There are still steps to take before quantum... (Score:4, Informative)
Diamonds are not a metal... and Diamonds have the highest thermal conductivity... the last thing you want here for semiconductor devices is a substrate with the highest electrical conductivity... you want a very good insulator, which also gets heat away very quickly... this is where Diamond layers come in... not solid machined diamonds, but diamond deposited or grown into a thin layer...
Re:I wonder... (Score:2, Informative)
The idea of Quantum Teleportation has been misunderstood. Quantum Teleportation is not like the Star Trek
Re:Void? (Score:2)
Re:Awesomeness (Score:2)
Not always. For instance if you have access to the
Public key algorithms are also vulnerable, as the private key can be lik
Re:Awesomeness (Score:2)
You're mostly correct. There is absolutely no reason for ordinary users to be able to read the
The public key probl