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Quantom processor?

  1. Sep 9, 2005 #1
    I have heared about quantom processor.
    Is this thing possible? are they close to create such a processor?
    A more general question. Are there any experiments that proove quantom physics is true?
    Or are there any applications based on quantom physics? or all people do with quantom physics is discuss about it in theory?

    Thanks in advance.
    Last edited: Sep 9, 2005
  2. jcsd
  3. Sep 9, 2005 #2

    The computer you posted from is a solid proof for QM. It wouldn't work if QM didn't work. And the computer is a pretty neat application too, isn't it?
  4. Sep 9, 2005 #3


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    Quantum physics is over 75 years old. It is as "true" as any theory gets, and is generally considered to be the most accurate, best-tested and useful scientific theory ever created. Virtually everything we know about atomic and sub-atomic particles is based on Quantum Mechanics in one way or another.
  5. Sep 9, 2005 #4
    As I know USB memories work on tunnelung (one of QM applicatiions)
  6. Sep 9, 2005 #5
    I assumed when I read the title that the OP was refering to quantum computing.... but the talk of whether QM has been proven made me wonder what he could have meant after all.
  7. Sep 9, 2005 #6
    I have just heard about something called a quantom processor of a computer.
    As you know the techonligy of today's processors is limited.
    The processors manufacturers said that not very far from today they will reach the maximum computing power from the current techonligy.
    However, I have heared about a new type of processor that have greater potential, and it uses some new way to move the data within the processor.
    Perhaps that data can move faster then the speed of light? faster then electrical current?
  8. Sep 9, 2005 #7
    In theory, quantum transitions are instantaneous i.e. take zero time, so it is very possible that data throughput could be vastly increased. The theory for quantum processing uses the quantum properties of particles, but as far as I know there isn't an effective, reproducible device that can harness this.
  9. Sep 9, 2005 #8


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    Data cannot be transmitted faster than the speed of light - this is fundamental. Existing theory is capable of yielding many new applications even if theoretical computational thresholds are within sight. I expect the cost of computing power to continue its decline.

    I would recommend that anyone resist the urge to think "We need a new theory." Just because we want nature to be able to break through "limits" does not mean that nature will comply with our wishes. There are many good reasons why Quantum Theory has developed the way it has. For example, it works!
  10. Sep 9, 2005 #9
    You are almost certainly referring to quantum computing. This technology is very much in its infancy. Enough work has been done to show that it is possible, but actually implementing a quantum computer with more than a few qubits is a tremendous feat.

    I also question your suggestion that these are a solution to the problem of our current processors reaching limits. Quantum computers can perform some tasks far better, but it is entirely possible they perform many other much worse. They are more likely to be a specialized device.

    In any case don't expect to see a "quantum processor" for sale in the next decade. Maybe not in the next few decades.
  11. Sep 9, 2005 #10
    Well, i am sure you are referring to the technological implementation right ? the theoretical principles behind it are, err, about 75 years old.
    The QM-computing aspect is all about implementing lots of matrices in a pc. In that respect each "classical" pc can execute every QM-operation. The big problem is finding out smart algorithms that allow is to extract info from the massive quantum-parallelism fenomenon. This extraction has to occur indirectly by measuring relative phases of the wavefunctions involved. Just look at how Deutch's problem is solved.

    Me too,

    quantumcomputing is a software thing. Improving the hardware is a totally different thing. In the pentium 4 for example, the basic ingredient (the MOSFET) is about 70 nm in length. Each CMOS-transistor has one PMOS and a NMOS, so the CMOS devive is 130 nm. Hence the name Intel's 130 nm-technology.

    One of the main issues in scaling down pc hardware is the gate dielectric that insulates the gate from the silicon substrate. In the pentium4, this layer is only 1.5 nm thich (about 5 atomic layers of SiO2). Due to this small dimenion, lots of drive current is lost. In order to keep on scaling down, the SiO2 is repaced by the socalled high-k dielectrics like HfSiO4. I explain all of this in my journal. Nowadays, people in the industry work on 45 nm CMOS devices with high-k dielectrics as the gate dielectric.

    My point is, this has NOTHING to do with quantum computing. Ofcourse, QM is widely used in this stuff.

  12. Sep 10, 2005 #11
    Well, yes. In fact, that might be why I used the phrase "technology" and not "theoretical principles."
  13. Sep 10, 2005 #12
    So quantom computing is just a new way to calculate things?
    So the difference between today's processor and quantom processor is only logical and not a different physical technology?
  14. Sep 10, 2005 #13
    To first (realistic) extent it would be something like that, yes.

  15. Sep 12, 2005 #14
    I think this is mistaken. Quantum computing is both a hardware and a software thing. In fact, it is a completely new way of thinking about information processing.

    Although you are right to say that quantum computations can be simulated on a regular PC by doing lots of matrix multiplications, the size of those matrices grows exponentially with the number of qubits. Therefore, simulating quantum computations seems to be intractible (in the complexity sense) for a regular computer.

    Although current technology makes heavy use of quantum mechanical effects (tunneling in transistors for example) it is not appropriate for quantum computing. For that we need systems that retain their coherence, i.e. a large number of systems can be kept in a superposition for a long time, and we need to be able to perform coherent operations on those systems.

    A large number of systems have been proposed for implementing quantum computers, including Nuclear Magnetic Resonance, ion traps, quantum optics, semiconductors and quantum dots. It is fair to say that all of these are at a proof of principle stage and a genuinely scalable architechture for quantum computing is still some years down the line.

    By the way, a lot of new ideas in theoretical physics are being developed in trying to build and understand these machines, so it is a little inaccurate to say that this is `just technology' (although I do not think it is wise to try and draw an exact line between physics and technology). These ideas are also used in testing quantum theory itself, and have recently had some impact on our understanding of many-body quantum systems.

    Of course, we also need developments in quantum algorithms and complexity (the software side if you like) in order to make this whole enterprise worthwhile, so that is currently also a very active area of research.
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