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1 Molecule Computes Thousands of Times Faster Than a PC
alexhiggins732 writes with this tantalizing PopSci snippet: "A demo of a quantum calculation carried out by Japanese researchers has yielded some pretty mind-blowing results: a single molecule can perform a complex calculation thousands of times faster than a conventional computer. A proof-of-principle test run of a discrete Fourier transform — a common calculation using spectral analysis and data compression, among other things — performed with a single iodine molecule transpired very well, putting all the molecules in your PC to shame."
I really hate it when people come up with the simple "Quantum computer 1000 times faster than conventional computer". It's not just overly simplistic, it's wrong.
Quantum computers can turn some problems that require exponential time to solve into a polynomial time. So instead of taking 2^n time, it might take n^3 time. That's cannot in any realistic way be described as being "X times faster".
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And that was exactly my final year Physics project, in 1984. Take a slide image, shine a laser through it, put that through a lense. The FFT would be formed at the focal point. We then could apply frequency filters (as another slide) and with another lense I could reconstruct the image (less filtered images). So with modern technology, ie LCD screens and cameras, you could dynamically FFT, filter and reconstruct moving images in real time.
I've never seen a quantum computing device smaller than the size of a small room, so I'm not really sure how fair it is to compare it to a PC.
Really the PC doesn't even use full atoms for calculations, it uses electrons and electron holes in the atoms, and its at least 2000 times smaller than any quantum device I've seen.
You don't really get to say its one molecule when its a device made up of a fuckton of molecules and you are comparing too it a PC which uses subatomic elements to actually do the work.
You have a fast calculator ... the size of a room ... which I can put 2000 slower and easier to make calculators in and end up faster.
Sure, eventually, they'll make it smaller and smaller, but your comparison is like saying using an f16 to deliver mail is faster than using a postal truck to deliver milk. Just because you make two statements that share a verb doesn't mean you've made a comparison thats in any way meaningful.
Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
Bah! People need to stop complaining when it turns out that an important incremental advance in the field of quantum computing isn't already a commercially viable quantum computer that's being integrated into a chip for release next week. There won't be commercially viable products for many years to come. What is needed many, many incremental improvements in a broad variety of disciplines. None of the proof-of-principle experiments around today are attempting to be demonstrations of viable technology. This experiment demonstrates that am arbitrary quantum state can be deterministically written to the vibrational modes of a molecule, allowed to evolve and be read out by projective measurement. It is an important result because it helps open a new avenue of attack: vibrational energy levels in molecules.
The experiment is a beast that requires expensive, ultra-fast lasers, pulse shaping optics, and a molecular jet. It won't be integrated into PCI expansion card anytime soon but the fact that it is possible to coherently prepare superpositions of vibrational modes in molecules is interesting in its own right and is potentially important for quantum computation. Another decade or three of fundamental research and well funded grad students (ha) are going to be required before we can expect a commercial application.
So if this is the future...where's my jet pack?
If you define enough real world processes as calculation, you prove none of our laws of physics are the real ones.
For just one example, Nature can't be storing irrational numbers as infinite series expressions (where would the infinitely large registers to store them be?). Another way to put this is, if some process in Nature counts as a calculation, Nature can't be doing that calculation using numbers such as pi or e, but rather finite approximations of such numbers, that allow results in finite time.
(Otherwise, somewhere 'outside' the observable universe, there is an infinite amount of storage available for each number needed, and some sort of mechanism that handles those calculations in what looks like finite time to any point of view inside the universe - congratulations, you've just proved both the omnipresence and the omnipotence of God - probably not what you were aiming to do).
There are other ways around this, such as claiming real world events are just approximations - but what does it mean to say that nature has approximated what would happen to that apple that just fell on Newton's noggin, if there had been an exact inverse square law of gravity inside our computationally finite universe? This sort of claim sounds suspiciously like Plato's cave. Is there an ideal law of gravity that is somehow more real than the law of gravity actually expressed in the universe?
Alternately, maybe the problem is with claiming that some things are computations, just because they can be interpreted as approximate (usually analog) computations by an observer, that also has other knowledge necessary to parse the events as the results of computations. That's probably just as likely to lead to wild implications, but at least they are different wild implications.
Who is John Cabal?
I think the real question should be how many measurements per second can you do.
This is what standard computes do. To get the next step, you have to measure/read the previous state. So you have just zero or one, because that is the easiest to measure. Then you measure in gigahertz.
How many measurements per second can quantum computers do?