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Record-Low Error Rate For Qubit Processor
An anonymous reader writes "Thanks to advances in experimental design, physicists at the National Institute of Standards and Technology have achieved a record-low probability of error in quantum information processing with a single quantum bit (qubit) — the first published error rate small enough to meet theoretical requirements for building viable quantum computers. 'One error per 10,000 logic operations is a commonly agreed upon target for a low enough error rate to use error correction protocols in a quantum computer,' said Kenton Brown, who led the project as a NIST postdoctoral researcher. 'It is generally accepted that if error rates are above that, you will introduce more errors in your correction operations than you are able to correct. We've been able to show that we have good enough control over our single-qubit operations that our probability of error is 1 per 50,000 logic operations.'"
Another few orders of magnitude and they might approach vacuum tube-levels of reliability.
Don't blame me, I voted for Baltar.
I always made a lot more errors than that when I played Qubit.
One error per 10,000? They have some serious catching up to do, Intel had managed just 1 error in 9 billion over 15 years ago! And the later Pentiums were probably even better than that!
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The problem is that once you know what the error is, you don't know where the error is.
I mean, once you know where the error is, you don't know what the error is.
I mean, err... I'm not sure.
If this "breakthrough" only just now made quantum computers practical, then how are quantum computers already commercially available?
An important thing to recognize is that most of this experiment was done with a single qubit. Practical quantum computing will need to have this sort of error rate for thousands of qubits. The good news is that the methodology they used looks very promising. They used microwave beams rather than lasers to manipulate the ions. This has been I think suggested before but this may be the first successful use of that sort of thing. As TFA discusses, this drastically reduces the error rate as well as the rate of stray ions.
We are starting to move towards the point where quantum computers may be practical. But we're still a long way off. In the first few years of the last decade a few different groups successfully factored 15 as 3*5 using a quantum computer. (15 is the smallest number which is non-trivial to factor using a quantum computer since the fast factoring algorithm for quantum computers- Shore's algorithm- requires an odd composite number that is not a perfect power. It is easy to factor a perfect kth power a bit by looking instead at the kth root. And factoring an even number is easily reduced to factoring an odd number. So 15 is the smallest interesting case where the quantum aspects of the process matter.) Those systems used a classical NMR system http://en.wikipedia.org/wiki/Nuclear_magnetic_resonance_(NMR)_quantum_computing which has since been seen as too limited. There are now a lot of different ideas of other approaches that will scale better but so far they haven't been that successful.
One important thing to realize is that quantum computers will not magically solve everything. They can do a few things quite quickly such as factor large numbers. But they can't for example solve NP complete problems to the best of our knowledge, and it is widely believed that NP complete problems cannot be solved in polynomial time with a quantum computer. That is, it is believed that BQP is a proper subset of NP. Unfortunately, right now we can't even show that that BQP is a subset of NP, let alone that it is a proper subset. Factoring big integers is useful mainly for a small number of number theorists and a large number of other people who want to break cryptography. There are a few other cryptographic systems that can also be broken more easily by a quantum computer but there's not that much else. However, that is changing and people getting a better and better understanding of what can be done with quantum computers. A lot of the work has involved clever stuff involving using quantum computers to quickly calculate stuff related to Fourier series. Moreover, once we get even the most marginally useful quantum computers there will be a lot more incentive to figure out what sorts of practical things can be done with them.
So the upshot is that these are still a long way off, but they are coming. The way it looked in the late 1990s or early 2000s it was reasonable to think that the technical difficulties would make them never practical. They still are a long way from being practical but right now it doesn't look like there are any fundamental physical barriers and it looks like in the long run the problems that do exist will be solved.
Am I the only one who has difficulty thinking of quantum computers as things that actually exist and do calculations? It's like my brain has placed "quantum computer" firmly into the category "things that are theoretically possible but unable to be built with current technology", and refuses to change it, even to "things that exist in the lab but won't be commercially viable for decades outside classified government work".
show that we have good enough control over our single-qubit operations that our probability of error is 1 per 50,000 logic operations.
They forgot to add: "we calculated this probability on our quantum computer"
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Depends on the operation. For 4195835/3145727 100% error rate was acceptable ;)
Is the probability of an error 1 in 50,000, is the error rate probably 1 in 50,000, or is the error rate 1 in 50,000?
What we really need is a "standardized" open-source quantum computing language so that we can develop and exchange quantum algorithms to prepare for the day when quantum computers are real.
Right now we have the QCL language, QCF for Matlab/Octave, and the Cove framework that could be used with any language, but it looks like there is really only a C# implementation right now.
None of these have really taken hold as a "standard" though, and probably elements of all of them could be brought together in something multi-platform and all-inclusive.
What do you get when you have THREE competing standards and you try to take elements of them to make something multi-platform and all inclusive?
FOUR competing standards
Yet another person who has no idea how standards actually work, but is apparently literate enough to read XKCD.
Yet another person who has no idea how standards actually work, but is apparently literate enough to read XKCD.
Do tell. How do you think they really work?
Clearly your sense of humor does not fully implement the standard.
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"There can be only one." is the motto. It is why Linux has never caught on outside of the techno-geek crowd. It is much easier if everything is uniform and doesn't change. And you don't have to worry about hundreds of different hardware configurations.
They are just answers to questions you haven't asked yet.
Slashdot's rate-of-post filter: Preventing you from posting too many great ideas at once.
Chances are pretty good that your Quantum Computer will be running at liquid helium temperatures, maybe 4 Kelvin or so. Your general purpose CPU won't. There have been projects to run CPUs at liquid-nitrogen temperatures, and that already tends to get into mechanical difficulties; you're probably not going to be running your overclocked Xeon down at 4K.
Also, the quantum computer isn't likely to be something you're pumping a lot of data through - you're more likely to set it up, have it magically give you a probably-correct answer, and feed that answer to another computer that figures out if it's actually correct and then does something with it. For instance, if you're using the QC as an oracle to factor large numbers, you'll have it give you the result, then let your general-purpose machine multiply the factors together to find out if they give the right result, and then you'll use a general-purpose machine to rip off the bank account whose private key you just cracked.
Bill Stewart
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I like standards. I believe everybody should have a set.
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It is why Linux has never caught on outside of the techno-geek crowd. ...and servers, and HPC, and embedded, and smartphones, and basically everything except for desktop computers, yeah.
Now if someone could just implement Shors algorithm all 1-bit encryption algorithms will be rendered obsolete!
...I'll wait.
Operation Guillotine is in effect.