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Michael Nielsen's Free Video Courseware On Quantum Computing 54

Posted by Soulskill
from the superposition-of-knowledge dept.
New submitter quax writes "Michael Nielsen, who co-authored the book on Quantum Computing, released a set of short video lectures on his blog this summer (link to Google cache). They make a great introduction to the subject. But here's the catch: Due to other work responsibilities, he stopped short of completing the course, and will only complete it if he sees enough interest in the videos. Let's show him some numbers."
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Michael Nielsen's Free Video Courseware On Quantum Computing

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  • I misread and thought that said Mike Nelson. Got excited about a Rifftrax about quantum computing.
    • by type40 (310531)

      I was expecting the lectures to be taught by Gypsy with color commentary by Crow and Tom Servo.

  • For me, a major fundamental revolution is one that goes beyond improving on itself. A concept or group of concepts that begins and in the end permeates nearly every product and concept throughout the human world.

    We are very much into the run of the "Information" or "Computer" or "Digital" revolution in how people are now in mass looking at every single mundane product or process and seeing how this "new" way of looking at things can change/improve/simplify. Evidenced by the Refrigerator with Ethernet port,

    • by JoshuaZ (1134087) on Saturday October 01, 2011 @05:24PM (#37579480) Homepage

      I don't know if you are serious or joking here, but you could definitely stand to take this course. You seem to be under a lot of misconceptions about what quantum computing can do.

      Quantum, or more specifically quantum mechanics will be the next Major human revolution.

      Quantum mechanics is used all the time by lots of devices you use. Small transistors work because of quantum mechanics. Lasers work off of lots of quantum mechanics. LEDs work off of quantum mechanics. Etc. Etc. There's nothing new about using quantum mechanics.

      and Quantum Transceivers to that all those Optical SFPs in your switches and routers won't need cables anymore

      This and almost every other application you mention is complete nonsense. Quantum mechanics does not allow you to transmit information in special ways. Entanglement doesn't let you get away with that. (This is as far as we are aware, ignoring for now certain very interesting results from CERN that are likely to be incorrect and are still being checked over. Even if this is correct, it is unlikely to allow actual FTL or the like but rather be other interesting new physics. And calling that simply quantum mechanics would be misleading.)

      You can do things with quantum computers that you can't do with conventional systems. What we mean by quantum computers are not computers that use quantum mechanics in general (since they all do that) but computers that can take advantage of entanglement. This allows certain processes to occur much faster than they can with a conventional computer. For example, operations with Fourier series become a lot easier, and it becomes much easier to find the period of a given function. This translates into being able to do certain classes of problems much faster.

      For example, it seems that using something called Shore's algorithm ahref=http://en.wikipedia.org/wiki/Shor's_algorithmrel=url2html-18175 [slashdot.org]http://en.wikipedia.org/wiki/Shor's_algorithm> you can factor integers faster on a quantum computer than you can on a classical computer. This is a big deal, but even this requires a lot of caveats. First, we can't actually prove that this is better than the best classical factoring algorithms. In most interesting formulations of this claim, it depends on the assumption that factoring is not in P, a claim that is strictly stronger than the claim that P != NP http://en.wikipedia.org/wiki/P_versus_NP_problem [wikipedia.org] (it is possible that factoring lies in P but one gets a large speedup of like Klogn or something like that to the quantum system. This is possible, but fundamentally less interesting and less useful.)

      There are other specific similar examples, and even a handful where we can prove that the quantum version is really better than any classical version. The most prominent such example is Grover's algorithm. http://en.wikipedia.org/wiki/Grover's_algorithm [wikipedia.org]. This algorithm allows you to search unsorted databases much faster than you can in a conventional setting. That's a really useful but ultimately high restrictive use.

      Now, in fairness to you there are some uses of entanglement and other interesting quantum phenomena which don't rely on quantum computing per se. So you may have been thinking of those. But those don't allow what you seem to think they can do either! The closest to anything like that is quantum encryption, which makes a system of encryption that is essentially unbreakable as long as our understanding of the laws of physics are correct. That's pretty cool but even that has its own limitations, and it turns out can in some specific circumstances be broken http://www.sciencedaily.com/releases/2008/05/080508143107.htm [sciencedaily.com]. There are other interesting technologies out

      • by Desmoden (221564)

        WOW! Here I was just relaxing on a Saturday morning imagining all the crazy possibilities if we end up being able to transmit state without any consideration of distance. Quantum computing as described in these great vids is just one example of how things can change.

        Personally, I don't believe in impossible. Between the Easter Bunny, Santa Clause and now the Speed of Light, I've learned not to let hard boarders block free thinking.

        Moving away from a world of just 0s & 1s and adding things like |0>

        • Between the Easter Bunny, Santa Clause and now the Speed of Light, I've learned not to let hard boarders block free thinking.

          Why not throw away conservation of energy, also? Don't let reason block your creativity, quantum computing could heat your coffee for free!

          • by Desmoden (221564)

            Now you are just being silly

            • Yes, and my point is: it's no sillier than suggesting that quantum entanglement can be used to transmit information faster than light.

              Really. In the current model of quantum entanglement, which is part of the foundations of quantum mechanics and exists more or less unchanged since (at least) the 1950s, it's very clear that information (or anything else) can't travel faster than light. Beyond that, there have been lots of experiments testing and exploring all subtleties of entanglement, since the 1970s. All

              • Really. In the current model of quantum entanglement, which is part of the foundations of quantum mechanics and exists more or less unchanged since (at least) the 1950s, it's very clear that information (or anything else) can't travel faster than light. Beyond that, there have been lots of experiments testing and exploring all subtleties of entanglement, since the 1970s. All the results conform in all aspects to the "standard" theory for quantum mechanics. All phenomena that we have been able to observe fit

                • [...] it was believed you can not watch one particel and notice when the entanglement is broken by the other one. This is disproved by experiments last century.

                  Can you post (established) references, please? The only thing I heard about that is a paper from B. Dopfer in 1999 (I can't find a link right now) where they supposedly were able to stop interference by measuring entangled particles. I have seen a few critics, but mostly the lack of references from other papers is what makes me suspicious about it: s

                  • Can you post (established) references, please?

                    I have read that in Scientific American, quite a few years ago.

                    And in you scenario, nothing depends on anyone's definition of "faster than light".

                    It does. As most physics accept that such watching on entanglements is/might be possible. However the general argument is: the first movement counts. Regarding "causality" at least.

                    However you have a funny argument ;D with your radio and train.

                    • I have read that in Scientific American, quite a few years ago.

                      Well, as great as Scientific American is, can we at least agree that it publishes a lot of stories about non-established and speculative theories? I'm talking about papers by real physicists that have been peer-reviewed and referenced by other physicists.

                      It does. As most physics accept that such watching on entanglements is/might be possible. However the general argument is: the first movement counts. Regarding "causality" at least.

                      I doubt that "most physics accept" that, at least in the terms you describe. Within one of the most basic foundations of modern physics (Special Relativity), it doesn't even make sense to talk about which came first between A and B if B is outside the light

                    • Quantum encrypted channels work on the exact same principle and are already in general use. I don't see your point.
                      Also I assumed Scientific American was a respected peer reviewed physics magazine. Am I mistaken here?

                    • Quantum encrypted channels work on the exact same principle and are already in general use. I don't see your point.

                      Quantum encryption, as all other established results that use entanglement (like quantum teleportation, etc.), don't presuppose or rely on entanglement being able to send information faster than light.

                      Also I assumed Scientific American was a respected peer reviewed physics magazine. Am I mistaken here?

                      Scientific American is a magazine that does science popularization, its articles are nowhere near the level of rigor necessary for a peer-reviewed physics journal.

                    • As I pointed out before: strictly speaking the information is not sent faster than light as the entangled particles have to be moved by "conventional" methods.

                      The "raw entanglement" or however you want to call it, the fact that entanglements break etc. is "transmitted" instantly.

                      After all this is the "god is not rolling dices" counter argument form Einstein.

                      If you want to argue about entanglements than this should be the most basic thing to know.

                      That the scientific american is not a reputated magazine is fo

                    • Sigh... I don't think we're going to make any progress.

                      I've explained to you that in current physics, it doesn't make any sense to talk about "instant transmission" in the sense you're talking about. I've explained that in the current model for entanglement, there's no need or place for any such "instant transmission". Yet you keep insisting on a non-standard model for entanglement where information is sent faster than light, but "it's ok because you had to send the particles beforehand" (which, I have ment

                    • Well,
                      then I simply don't get your point.

                      Yet you keep insisting on a non-standard model for entanglement where information is sent faster than light

                      Do you want to claim that breaking entanglement is not instantly? Sorry, but then you are a bit out of the loop. It was never assumed that it took any time to be observed. It was assumed "it could not be observed". And this later point has changed in recent history. It was always clear that breaking entanglement has its "effect" transported instanly regardless of

                    • Do you want to claim that breaking entanglement is not instantly? Sorry, but then you are a bit out of the loop. It was never assumed that it took any time to be observed. It was assumed "it could not be observed". And this later point has changed in recent history. It was always clear that breaking entanglement has its "effect" transported instanly regardless of distance. That is not my "interpretration" but what is tought in school since ever.

                      "Breaking the entanglement is instantaneous" is a question that, currently, nobody knows the answer, but that's because this question is about the interpretation of quantum mechanics [wikipedia.org], and can't be settled, as far as we know, with experiments. What people do believe, though, is that even if breaking the entanglement is "instantaneous" (I write it in quotes because that can't even be made precise with current physics, as I've explained), no information can be sent "instantaneously". I'm curious to see this ar

      • I think that if a robust quantum computer were developed, specific algorithms would follow. Quantum computing allows you to exploit a larger computational basis than classical computing for a given number of (q)bits. The extra internal degrees freedom in a quantum state, thanks to entanglement between the elements, mean that the state-space is much larger than for a classical system and the promise of using that as a computational basis is hard to ignore.

      • by AP31R0N (723649)

        Does Grover's algorithm determine is something is NEAR or FAR?

        Stupid filter....

    • by narcc (412956)

      I've had a Quantum Fireball hard drive for years.

      I can't use it anymore though. Every time I've tried to read from it, my cat dies.

    • Re: (Score:3, Insightful)

      by maxwell demon (590494)

      Quantum, or more specifically quantum mechanics will be the next Major human revolution.

      Actually quantum mechanics already is the previous revolution. Lasers are quantum. Semiconductors are quantum. Without quantum mechanics, our computers would still be big monsters of tubes with the power of a pocket calculator. The giant magnetoresistance, which is the base of our high-density hard disks, is a quantum effect. Without quantum mechanics, the whole information technology revolution could not have taken plac

  • I've read a few articles on quantum computing before this, and while they tend to give a general idea of what it's about, they tend not to go into any depth on quantum logic and what you can actually do with individual qubits (or if they do, they're so dry I end up falling asleep before that point). These videos show what kinds of operations you can perform on qubits mathematically and how you can form concrete quantum circuits/algorithms out of quantum gates. The bits on superdense encoding and quantum tel

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