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What is Quantum Physics in simple?

  1. Jun 11, 2007 #1
    hi!

    is quantum physics that difficult to understand?
    because i had read the explanations given in the internet but couldnt get any proper explanation.

    thankz in advance!
    (ps. please explain quantum in simple)
     
  2. jcsd
  3. Jun 11, 2007 #2

    G01

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    Quantum Physics is considered conceptually difficult because it is not based off of any of our previous knowledge of the universe.

    Asking us to explain the whole of quantum theory to you in simple terms is a lot to ask. It covers a vast ammount of material, enough that trying to cover it in a post on a message board would accomplish hardly anything.

    I guess my point is that, if you looking for an explanation of quantum physics based off of previously held notions and experiences you have in the world, your not going to find it. Quantum Physics just cannot be explained in classical terms because it just isn't classical.

    I suggest finding a book, many people here can give good reccomendations, and going from there. I read the small book, "Introducing Quantum Theory" while I was still in high school. It was non-mathmatical and gave decent description of the history and developement of the theory. Looking back on it now as someone who knows more physics, I think it was a decent place to start.



    EDIT: Also, you may end up seeing stuff that says "Quantum Physics says this, says that,etc." Alot of crackpots try to use Quantum Physics to support everything from psychic readings to the belief that we can change things around us by thinking. This is all crap and has nothing to do with Quantum Physics. If you come across anything like this, be VERY skeptical. Also, do not use the movie "What the Bleep Do We Know?" as a source of information on quantum physics. It falls into the above category. In fact, it may be the epitome of the above category!
     
    Last edited: Jun 11, 2007
  4. Jun 11, 2007 #3
    I don't think quantum mechanics is THAT difficult and abstract as people (specially crackpot "physicists" as G01 mentioned) claim.

    just know some algebra and differential equation and accept the Schrodinger's equation and you are all set.
    Quantum mechanics is very axiomatic (depends on how you learn it). If you know the mathematics, then things will become intuitive. For instance, the uncertainty principle is simply the Cauchy-Schwartz (a mathematical theorem) and nothing more that that. (it's not like a particle flies in something bizarre dimension then comes back from the future and destroy the world... no, it is a mathematical theorem, and nothing more than that)


    take a look a griffith's book and the whole idea of quantum mechanics will become demysticified.

    edit: very often, the internet just make things more confusing that it actually is. Grab a book (Griffith's introduction to quantum mechanics) and all your questions will become clear.
     
    Last edited: Jun 11, 2007
  5. Jun 11, 2007 #4

    G01

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    I agree. If you have knowledge of calculus and differential equations, I also Reccomend Griffiths "Intro to Quantum Mechanics" as a good book.
     
  6. Jun 11, 2007 #5
    Aye, Griffiths' is surely the most "readable" undergraduate QM textbook.
     
  7. Jun 11, 2007 #6
    whats the name of this book?
     
  8. Jun 12, 2007 #7
    Some concepts to consider in quantum mechanics:

    The correspondence principle correlates macroscopic with microscopic physics.

    There is (the Heisenberg uncertainty principle) a minimum product (~h, the Planck constant) for the uncertainties of energy and time, or position and momentum.

    Quantum mechanics applies best at small distances and high energies.

    (Sub)atomic matter and energy both display wavelike and particle-like qualities.

    (Sub)atomic states embody Planck constant discreteness.

    Space(time) is believed to become foam-like on microscopic scales.

    Observable outcomes on quanta are affected by measurement itself.

    Schroedinger's equation expresses conservation of energy for wave dynamics.

    Probability is calculated by integrating the wavefunction (a solution to Schroedinger's equation) over the variable in question.

    Macroscopic tests of quantum mechanics include Josephson junction superconductivity.
     
    Last edited: Jun 12, 2007
  9. Jun 12, 2007 #8

    G01

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    Introduction to Quantum Mechanics by David J. Griffiths
     
  10. Jun 12, 2007 #9
    thank you!!
     
  11. Jun 12, 2007 #10

    G01

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    The Book does require knowledge of Calculus and Differential Equations, just in case your not up on the math, and want to do the problems.
     
  12. Jun 12, 2007 #11

    malawi_glenn

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    Niels Bohr said once:

    If you think you have understand quantum mechanics, you have not understand quantum mechanics.

    =P
     
  13. Jun 12, 2007 #12
    what did neil bohr mean by that?
     
  14. Jun 12, 2007 #13

    malawi_glenn

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    that what "DrWatson" said, that reading books like the one he recomend, you will understand QM. We can not understand QM in intuitive way.

    At what level do you study physics yourself?
     
  15. Jun 12, 2007 #14

    chroot

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    You can completely understand the theory, in the sense of being able to solve problems, analyze experiments and derive the correct predictions, and so on. Many people (tens or hundreds of thousands) understand the theory in this way.

    On the other hand, quantum mechanics is so unintuitive that many people, even after learning the theory intimately, still have trouble accepting that the universe really behaves that way. Quantum mechanics is very difficult to appreciate from the perspective of human experience -- unlike the motion of billiard balls, which clearly makes "sense" to anyone who studies it.

    - Warren
     
  16. Jun 12, 2007 #15
    hm... i dont exactly know the level of physics i am at present i mean i dont know what it is called
     
  17. Jun 12, 2007 #16
    so QM explaines how the universe behaves.....
    does it also state something about the behaviour of atoms and electrons?
    i had read something about that once..
     
  18. Jun 12, 2007 #17

    chroot

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    Quantum mechanics is essentially the study of how very small things "move," if they can be said to move at all in the usual sense. Quantum mechanics does indeed have the power to describe how electrons behave inside atoms. The canoncial system studied in basic quantum mechanics classes is the hydrogen atom: a proton and an electron together in a bound system.

    Quantum electrodynamics is a physical theory, based on quantum mechanics, which describes the interactions of light and matter.

    - Warren
     
  19. Jun 12, 2007 #18

    G01

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    To help us understand the level of physics you are at answer these questions:

    Can you do general physics problems, such as ones from a standard college general physics text, or do you study more of the qualitative aspect of the material?

    If you can do general physics problems, how far along are you? Have you completed a general physics course? Can you do problems beyond general physics, such as problems in Modern Physics?

    What level of math have you studied up to?

    These will help people judge the level you are at, and recommend the best study material.
     
  20. Jun 12, 2007 #19
    actually richard feynmann said that
     
  21. Jun 13, 2007 #20
    thank you!!!
     
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