Research Team Makes Quantum Computing Progress 125
Timogen writes to tell us Wired is reporting that a research team is reporting that they have found a way to "controllably couple qubits" bringing us one step closer to quantum computing. "In classical computer science, bits -- or binary digits -- hold data encoded as ones and zeros. In quantum computing, data is measured in qubits, or quantum bits. As such, a qubit can have three possible states -- one, zero or a "superposition" of one and zero. This unique property theoretically makes quantum computing able to solve large-scale calculations that would dwarf today's supercomputers. But qubits in isolation are not very useful. It's only when they can be connected to one another that large-scale processing becomes possible."
Re:Was this a quantum leap? (Score:5, Funny)
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Re:I wonder (Score:4, Funny)
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You know what else was measured in qubits? (Score:5, Funny)
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What so the quantum state animals were both inside and outside the ark, until he counted them?
I guess he must have also had some Schrödinger Cats onboard as well then.
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Sorry to be the one to break it to you...
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I bet you don't even believe in talking snakes either.
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Also remember when it talks about "the face of the earth", it is refering to the local area that was known about, which was common for the time. Now before anyone attacks this logic - with the account with the birth of Jesus it says that Ceaser taxed the whole earth, obviously talking about the Roman Empire (which was the known world), Rome didn't tax the goths, chinese etc as they weren't part of their world. So don't be so quick to jump the gun with assumptions about the bible.
So when the bible says that Noah was 600 years old, what did *that* mean? You know, there's a reason why bible supporters are called apologists... they're always having to apologize for all the problems that no logical person would ignore.
Just remember that until the city of Ninevah was discovered many people thought that it was a made up city in the bible, and that many of the cities mentioned in the bible were thought not to exist which are now known to have (Ur, Ninevah etc)
Let's say I write a book about a city called New York, two tall buildings of concrete and steel, and winged creatures that attacked those buildings and conquered them. I then added in a leader named Bush who was in communication with aliens from Alpha Centauri and Bush
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A translation error. That's what you get for measuring ages in moons and translating them to years. It's why Methuselah is so old; divide by 12 or so and you get a really reasonable (but still high for that time) number. At a certain point you see a correction in the huge numbers for the ages and then you get to the "normal" ones again.
The problem isn't so much in the apologists; it's the literalists who don't want to admit that t
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So it's not that God doesn't exist or that he doesn't perform miracles, he's just a shitty editor.
The fact that the supreme word of God needs to be translated, edited and revised speaks volumes on how reliable it is.
So which parts of the Bible are the actual words of God? The baby killing? Wife beating? Slave owning?
No, only the "good" parts of the Bible are considered accurate and that seems a little too c
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So, how many arks can fit on the head of a pin?
Three states? (Score:5, Informative)
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Analog vs Quantum (Score:2, Interesting)
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You can use tri-state in modern computers (and I believe it is used) the problem comes from interference, modern microprocesser's already battle quantum effect and bulk effect, adding anouther layer make things much harder.
Quantu
Re:Three states? (Score:5, Interesting)
As usual, Wikipedia has an article [wikipedia.org].
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Well, tri-state isn't really trinary per se, although outputs still have zero, one, and a high-impedance output state. The purpose of that high-impedance output is so you can stack multiple output lines (ie, multiple devices) on a bus, without them trying to overwrite each other, and you just un-tristate the relevent device through some sort of addressing.
Despite having what appears like three output states, tristate is not trinary for a few reasons. Firstly, the c
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As another poster mentioned, the "tri-state" used in computers isn't trinary, it's binary with a 3rd state which is "off", as in not driving any output voltage at all.
The reason why we use binary and not trinary is because binary is simple circuit-wise -- you drive the output as hard as y
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http://en.wikipedia.org/wiki/Ternary_computer [wikipedia.org]
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But you're right that there are an infinite number of superposition states.
All states (Score:2)
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I think Wired's simplification is appropriate. My understanding of quantum computing is that a qubit can collapse to a 1, or it can collapse to a 0, or it can be in a superposition of 1 and 0. The one and zero states are pretty easy to understand--they're basically classical. It's the superposition that's the weirdo "state", and it's also the thing that makes quantum computing fundamentally different from classical computing. So, for a magazine that is trying to explain the forefront of quantum computin
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No, a state in a superposition REALLY IS in it's own state, the Zero and One states it's a superposition of only act as a basis, but a qubit really is in a single state that happens to be a linear combination of those basis states. You can choose any two points on the Bloch Sphere to be a basis, and if you want you can even rewrite the superimposed state as being a well-defined ZERO in the newly-defined basis.
The
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Right what we needed (Score:5, Funny)
Then again, every time I use Windows, I already have the hunch that this "maybe" has already been implemented. If only in software so far.
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Re:Right what we needed (Score:4, Funny)
I think it's more like Cancel, Allow
Sorry about the horse...
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How about "Yes, No, Mu [wikipedia.org]"?
It's appropriately Zen, and overloads the symbol for the muon to the delight and confusion of everyone (and isn't delight and confusion what quantum physics about in the first place?), which makes it even more appropriately Zen.
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Or Yes, No, Cancel.
A, B, Both.
It's a third state. We can interpret only in context. Heck, not everything can even be expressed as having 3 states. (On, off, no power?) And many can be expressed as having more.
Ultimately it's just another set of physics which can represent a state machine. It seems that the progress made is that a quantum 'gate' can be created. However, lacking any kind of timing mechanism (anyone know a periodic oscillater than can produce microwave radiation?), it s
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It is much stranger than trinary values like red,green,blue.
The implication is that all the solutions are in there and when you pick the input states everything stabilizes to the correct answer *PPOPOOF*.
The best doc on the subject that I read is the instructions for the perl module docs for Quantum::Superpositions [cpan.org]. It is not in any way necessary to know (or even like perl) to read the pod pages for the module.
It was fashionable in perl, for a while, to try to solve problems with superpositions. I
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{
True,
False,
FileNotFound
};
http://worsethanfailure.com/Articles/What_Is_Trut
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-the hermit
Made Progress? (Score:5, Funny)
But until you actually make an observation by clicking on the link and reading the article, the outcome will still be indeterminate.
Re:Made Progress? (Score:5, Funny)
Re:Made Progress? (Score:5, Funny)
Hmmm..that's funny. The cat looked alive to me.
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I just want to know what's with all the steel chambers.
Re:Made Progress? Cat? (Score:4, Funny)
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Zombie cat. (Score:1)
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Re:Made Progress? (Score:4, Funny)
Well thanks a lot. Due to the nature in which you observed the link now everyone is going to see a dead cat. If only you clicked that link or looked at your monitor slightly differently that cat would be alive. You killed that cat. Next time think before you observe.
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I call bullshit. ACs don't have enough substance to cause a collapse.
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Listen up everybody! (Score:5, Funny)
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Interesting (Score:2, Insightful)
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Checklist needed (Score:1)
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...I could go on all day...
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You mean: Features Quantum Entanglement - Yes, No and Maybe.
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David DiVincenzo, of IBM, listed the following requirements for a practical quantum computer:
- scalable physically to increase the number of qubits
- qubits can be initialized to arbitrary values
- quantum gates faster than decoherence time
- Turing-complete gate set
- qubits can be read easily
This is from wikipedia's quantum computer [wikipedia.org] entry.
Unfortunately the article itself does not use that list, so their progress is hard to judge...
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1. Propose a quantum computer
2. ???
3. ???
4. ???
5. ???
6. ???
7. (etc)
n. Profit!
I think we're up to 3.
One step away from breaking all encryption? (Score:2)
Dr. Tsai says the NEC group is working on a more complex, five-step procedure that will allow some basic logic to be carried out. He hopes it will be completed by the end of the year.
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My understanding was that for example, if you had an encrypted file, quantum computers could decrypt it by passing all possible keys at the same time, giving you the "answer" (0 or 1) near instantaneously. If the researchers have just "one" logic gate, isn't that enough to solve the decryption problem?
Quantum decryption (Score:5, Informative)
There are two specific algorithms for quantum computers that have a big impact on encryption:
Shor's algorithm [wikipedia.org] lets a quantum computer factor a number in polynomial time. It requires a number of qubits that is some multiple (greater than 1) of the number of bits in the number. So, once we have quantum computers with a few thousand qubits, all encryption mechanisms based on the difficulty of factoring numbers (which is most mechanisms) are broken.
Grover's algorithm [wikipedia.org] lets a quantum computer look up an entry in an unordered dictionary in N^.5 time, where N is the number of entries in the dictionary.
Grover's algorithm, if I understand it properly, is a Big Deal. When they say "look up an entry in a dictionary", they really mean "give an entry for which an arbitrary algorithm returns a desired value". Essentially, it means you can solve any NP problem in N^.5 time. For example, with a simulation algorithm you could find a satisfactory design out of 100,000,000,000,000 different computer designs in 10,000,000 applications of the simulation algorithm, as opposed to the 100,000,000,000,000 applications it could take on a normal computer.
Another example of applying Grover's algorithm would be cracking a password (regardless of the encryption algorithm used). Let N be the number of possible password combinations. On average cracking a password would take N/2 applications of the encryption algorithm using a normal computer; it would take N^.5 applications using a quantum computer.
Quantum computing doesn't invalidate encryption, but real QC would essentially invalidate encryption algorithms based on the difficulty of factoring large numbers and substantially reduce the difficulty to crack any other algorithmic encryption.
Of course, one time pads are still totally unbreakable if used properly...
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Not quite. Grover's algorithm will give you a quadratic speed up in searching problems. This means if a search can be completed in O(f(n)) time then with Grover's algorithm it can be completed in O(f(n)^.5) time. If f(n) is superpolynomial, then f(n)^.5 will also be superpolynomial, so this won't let you calculate anything polynomial time that wasn't already calculable in polynomial time.
Grover's algorithm is still a huge deal though. It can be
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Yeah, crap, I shouldn't have said that. I think the rest of the post is on target, though...
I wasn't trying to claim that Grover's algorithm would let you solve problems in polynomial time. I may well have expressed the time taken incorrectly... hmm, it seems to me that saying "it takes N^.5 applications of the algorithm versus N applications for a classical computer" is equivalent (in terms of the speed) to what you said.
I do think that qual
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Remember, here the N I'm talking about is the number of possibilities, not the amount of data it takes to represent those possibilities. So for 16 million possibilities the N I'm talking about is 16 million, not 24 (the number of bits it takes to represent 16 million possibilities, and the typical usage of N in the O(N) notation).
Of course, you're right that my comment there didn't include the time it takes for f(x) to execute, but for many applications th
Grover's algorithm is no problem for encryption (Score:2)
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I imagine that there are well known non-factoring based private/public encryption (elliptical, etc.). We could switch to those. That doesn't help with data that's already out
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Can someone please explain this to me... (Score:5, Interesting)
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You can measure your system and observe the value sqrt(k) for some random k between 1 and 2^n. This doesn't buy you anything as it is trivial clasically to choose a random k and compute its sqrt.
Or you can take "glurg" and apply some funky quantum gates to it and *then* measure your system and get n strange bits out of it. This can buy you something if you take a quantum computing class to learn how to design a useful quantum post-operation and analyze exactly what the out
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Those aren't the sorts of problem you ask to a quantum computer. Even if
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Example: Searching for an encryption key. (Score:1)
Now consider the 128 qubits together as a set. You have to pull out the one
Re:Can someone please explain this to me... (Score:4, Informative)
"... is reporting ... is reporting..." (Score:1)
- Mensa Grammar Police
My Qubits are aching (Score:2)
To your sarcasm, sir, I respond with austerity : (Score:2)
Porting software to Quantum Computers (Score:1)
As an example, our research group has beeen working feverishly on porting Q-Bert [yimg.com] to Qubits.
Tri-State? (Score:2)
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You're wrong in doing that, but you're also wrong in assuming that it can be made intuitive. It just isn't, in much the same way that if you think quantum mechanics is intuitive, you probably don't understand it. Nothing personal; this stuff really is that complex.
Summary = Generic fluff about qubits (Score:1)
So let me try to quote the relevant bits (hehe) from the article:
Until late last year, if you had qubit A and you needed it to be coupled to qubit B in order change the state of qubit B, you'd have to keep that link constantly active. This link -- the coupling -- is made possible by quantum entanglement. But keeping the link active is a problem because it will also change the state of qubit A -- when y
And the operational part... (Score:1)
This is too confusing! (Score:2)
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But What Direction? (Score:3, Funny)
Quantum Computing Timetable (Score:2)
Wired? (Score:2)
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