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Significant Advance in Quantum Computing
wcitech writes "Apparently scientists have been able to create circuitry that mimics the behavior of atom pairs by using superconductors." From the article: "The work, reported in the Feb. 25 issue of the journal Science, demonstrates that it is possible to measure the quantum properties of two interconnected artificial atoms at virtually the same time. Until now, superconducting qubits--quantum counterparts of the 1s and 0s used in today's computers--have been measured one at a time to avoid unwanted effects on neighboring qubits." The second Quantum computing revelation this month, in fact.
Well, obviously it isn't ready but there are steps between "hey, I've got a good idea" and "you want to buy this product from me???"
Actually, it can also be in a superposition of being both ready and not at the same time
If your idea of quantum computing is a computer only capable of a handful of bits and costing millions, then yes... the technology is ready. Would you like fries with that?
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Of course! We created God...in our image and likeness, no less.
"Once we've identified and embraced our sickness, we'll have strength...and that's when we get dangerous." - John Waters
"I don't see Quake 10 on the list, so what's the point?"
accurate video game physics down to the quantum level
Nothing.
No, wait. It means that we're going to have to stop lying to ourselves, admit that no communication mechanism can ever be capital-S secure, and listen to the geeks who've been saying that security needs to be convincing people not to try, detecting when they do, and being able to recover from any intrusion.
I don't see Quake 10 on the list, so what's the point?
The point, of course, is to solve the factoring, discrete log, and quantum physics simulation problems.
Whether that is worth the resources being thrown at it is an exercise for the reader.
(The more I learn about quantum computing, the less likely I think it is and the more I wonder what all the fury is about. I expect this will collapse in about two years and be remembered right next to the "great" AI era of the 80's. Hey, maybe I'm wrong... and hey, maybe 80's style AI programming really is the path to strong AI and we just didn't try hard enough... but I'm not holding my breath and the burden of proof remains on the researchers.
It reminds me of FTL or teleportation; with every little "advance" physics fanboys crow about how much "closer" we are, whereas I see an ever-refined understanding of why the thing we are looking for is still impossible and the potential loopholes slamming shut.
Preparing for "-1, troll" from physics fanboys in five... four... three...)
A quantum register does not actually represent all possible inputs. It represents a superposition of all possible inputs; this is a very important distinction.
When the register is 'read' after a computation, it contains exactly one result representing the results of one random possible input. Using a classical algorithm with the register would be exactly like a normal computer with a random setting as the input.
Getting anything special from a calculation from a qubit register is extremely tricky. Shor's algorithm does a special quantum fourier transform on the register to get the most common possible output [this is a metaphor] and only works because the values of the qbits are not independent (and thus do not represent all possibilites). The algorithm must be run several times to even get a statistically meaningful result.
... so that when you collapse the wave function, voila! the correct answer is revealed, as if by magic?
Most of the time.
There have been no algorithms devised for quantum computers so far that can solve NP-Complete problems like the Travelling Salesman Problem in polynomial time.
It *is* possible to achieve a square-root speed-up on essentially any problem in NP using Grover's algorithm, but it has also been shown that this is the best that can be achieved without exploiting the structure of these problems in some way as yet unknown.
It would be a major advance if anyone did come up with such an algorithm, and in fact (I think) most people believe it's not possible. Incidentally, resolving this question either way would not imply that P = NP or P != NP.
there is no quantum algorithm to speed up np complete problems. this whole post is just not right