Slashdot Mirror
Research Team Makes Quantum Computing Progress
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."
Or just a regular one?
If they turned into an Asian woman in California during the 1940s...
Sig Follows: "Suppose you were an idiot. And suppose you were a member of Congress. But I repeat myself." -- Mark Twain
The Ark. That's right: Noah's Ark.
Qubits can have an infinite number of states between 0 and 1 (inclusive). "Superposition" does not describe a single state, it just means that it's somewhere in between.
It was also the gold currency in the original Galactica series.
The tri-state computer: Yes, no and "maybe".
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.
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
There are two possible end states: the researchers made progress or not.
But until you actually make an observation by clicking on the link and reading the article, the outcome will still be indeterminate.
Slashdot's got an article that says "Timogen writes to tell us Wired is reporting that a research team is reporting that"...
Just junk food for thought...
Kind of. But then you can still create qubits in entangled states, like, upon measuring two qubits you get always one "1" and one "0" , but you don't and cannot know which is which until you measure. You can't do that with an analog computer.
It feels as if we were recreating computing, making the first steps again that were made during the 1920s-1940s in computing.
Mom: Jimmy were you looking at porn?!
Kid: I really couldn't say! The site was caught in superposition.
Mom: Don't take that tone with me! What is that, some new porno move?
Kid: No, I swear, it's...
Mom: Go to your room!
Kid: But Mom!!!
Mom: I said GO!
TLF
I do not respond to cowards. Especially anonymous ones.
I love the idea of quantum computing but I'm tired of seeing articles that say "Progress has been made in QC" or "Breakthrough in QC". Why don't we have a checklist available so that we can cross something out on the checklist every time progress is made. This way we can see exactly how much closer we are to getting QC to the market.
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?
Namaste
...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. Trying to understand this claim better, I followed wired's link to this article, which states:
...in a QC, the bit is upgraded to a quantum bit, or qubit, that doesn't need to choose between 1 and 0. It can be both at once. As a result, a memory array of n qubits can represent every number between 1 and 2^n simultaneously. A QC's capacity doubles with each additional qubit. It may be humbling that the world's largest QC is currently only 7 qubits in size, and can barely process single-digit numbers. But a QC of 333 qubits would be able to perform operations instantaneously on every number between 1 and a googol (10^100), a value considerably larger than the number of atoms in the universe. To carry out addition or multiplication on every positive integer between 0 and 10^100 would take one of today's supercomputers several quadrillion years as it marched through one number at a time. But a QC would perform the calculation all at once, and it'd be done. I can (kinda) understand how n qubits can store every number between 1 and 2^n, and I can (very vaguely) imagine how that allows one to perform calculations on all those numbers simultaneously. Assuming all of that is true and good, what would one do with the output? For example, let's say I take sqrt(1 to 2^n) and get glurg as a result. Does glurg really hold the sqrt of all those numbers, and if so, how do I access them individually?Unforgivable!
- Mensa Grammar Police
I tried to read the article, but my qubits started aching and my quantum bits started acting up. Somebody summarize me whats going on in this article please.
Read radical news here
I believe this was done by Japanese researchers. RTFA.
As you know, quantum computers require a recoding of applications to take advantage of the qubits.
As an example, our research group has beeen working feverishly on porting Q-Bert to Qubits.
When these texts compare bits to qubits, they use to say that the former has two possible values (1 and 0) while the later has an additional superposition state. This makes sense when you consider the bit as pure information. But AFAIK then we're comparing apples to oranges, since qubits are physical entities, while bits are logical ones. IMHO, a more correct comparison would be between qubits and electrical gates, which are bits' physical counterparts. And, guess what? Gates actually have 3 states too (0, 1, and Z), even deriving their name from this.
Since I come from an electronics background I cannot help myself but to think on qubits' super-imposed 3rd state as an improvement over good old Z. Maybe I'm wrong in doing this, but at least it makes the whole subject a little more intuitive for me.
Conservatism: (n.) love of the existing evils. Liberalism: (n.) desire to substitute new evils for the existing ones.
Quantum computers don't turn NP into P. I.e. they don't let you solve NP problems (where recognizing a correct answer is very easy but you have to test all answers to see which is correct) in an amount of time that is a polynomial function of the size of the input.
There are two specific algorithms for quantum computers that have a big impact on encryption:
Shor's algorithm 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 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...
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 you only want to change the state of qubit B.
For many years, scientists have been trying to figure out how to couple qubits for very short periods of time, just long enough to conduct a two-qubit operation, and to immediately shut it off once completed.
If controlling this coupling can be achieved, then larger computer logic operations should work.
For many years, scientists have been trying to figure out how to couple qubits for very short periods of time, just long enough to conduct a two-qubit operation, and to immediately shut it off once completed.
If controlling this coupling can be achieved, then larger computer logic operations should work.
First, the team took a qubit A in superposition and a qubit B in either state zero or one. Next, they coupled the two qubits using a microwave focused on a third qubit, which entangled the other two. Nearly instantaneously, both qubits would be in superposition and the coupling would be turned off. Finally, the superposition for qubit A would remain -- preserving its initial quantum state. I have been staring at this for quite a while wihtout quite getting it. Did the superposition of A get transferred to B or not?
RTFA yourself. What do you think Dr. Tsai's nationality is? Does his name look Japanese?
It must have been something you assimilated. . . .
From the summary:
"It's only when they can be connected to one another that large-scale processing becomes possible."
Is it Beowulf Quantum Cluster
or
Quantum Beowulf Cluster?
Sincerely,
Kilgore Trout
P.S.: In Soviet Russia, Quantum computing progress makes research team.
Hah! I knew I would be modded down. This downmod is perfect proof of the cultural cowardice and insecurity of the U.S.
A better way of putting it is that a Qubit has all states simultaneously. For example, both zero and one. You can talk about the probability that it will collapse to zero or one, but you can't average the probability to say that it is between 0 and 1 since there aren't any states between 0 and 1.
The world is made by those who show up for the job.
Dead... and alive? Zombie cat! http://nitespyder.com/CatHiss.jpg
Let us say you have 64 qubits representing all possible keys. Now do the encryption and xor with known ciphertext. Now you have 64 new qubits, with a superposition of 2^64 states, only one of which is all zeroes. However when you put that together with the 64 bits representing all possible keys, you don't have a superposition of 2^28 states, only of 2^64 states, since each state in the result corresponds to exactly on "key state".
Now consider the 128 qubits together as a set. You have to pull out the one state which has all zeros in 64 lsq (least significant qubits). You can do a bit operation, for example, that combines the key bitwise with the result so that only if the result is all zeros will it leave the key intact, otherwise it will zero out all the key qubits (a small handwave here). Now you have a supeposition of 2^64 states, where all except one state is all ZERO qubits, and the one exception is the key you want. Now you have do some operation (MASSIVE handwave) to filter out which qubit is ALL zeros and which is one one and (2^64 - 1) zeros superposed. I am told this can be done, but I have no idea how.
I need Ted Stevens to provide me with a simple explanation of how this works!
Hopefully I didn't put any [] around my words.
As far as I can tell this is an excellent summary of the problems involved in QC, and should get greater visibility.
The more progress we know the researchers made the less we can know about how close they are to a solution.
Ceci n'est pas une signature.
"ehehe hehe hehehehe hehe he he heheheeh ehe ehe he he. heh ... ehe. heh ... peh ...."
Read radical news here
The last line of this post is both funny and not funny at the same time.
..
Until you read it, you will have no idea which one it will be.
shit.
Here's where they're at... they know exactly how close they are to success. They just don't know how fast they're getting there.
Never shake hands with a man you meet in a fertility clinic.
One colour at first, if you want to,..but just go for the whole spectrum. (not just the visable light)
Yourve allready got the bits, just put them together.
"Wired" is reporting that the journal "Nature" is reporting on this. Why do we insist on going through middle men?
In terms of private-key encryption, it's very easy to counter the improvement given by Grover's algorithm - just use double sized keys. Instead of using AES-128, use AES-256... This is because sqrt (2^256) = 2^128.
The AACS key is NOT 0xF606EEFD628B1CA427BEA93A9CA9773F
What does the parent post mean? Seriously.
Yes, there is a cat. It's in the bin.
The Tao of math: The numbers you can count are not the real numbers.