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What makes quantum mechanics so interesting?

  1. Dec 31, 2004 #1


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    What about the quantum mechanics captures your interest?
  2. jcsd
  3. Jan 1, 2005 #2
    If there is one part of QM which interests me, it would be the measurement problem, the whole observer collapsing the wavefunction thing. I like to think that there's a physical explanation out there which explains this, rather than the whole consciousness crap.
  4. Jan 1, 2005 #3


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    Consciousness crap?

    I though the solution to Schrödinger's car paradox was precisely that the cat, as a "macroscopic body", auto-measures itself at every instant! At least that's what my college teacher told me.

    I asked him after that how big, or what caracteristics must a system have so that it auto-measures itself (i.e. loses its wave properties). He said this barrier is unclear, but the limit must be very small because I recently read in a science mag that a bunch of people had succeeded in keeping a large nucleus (140 nucleons or so) in the wave state and they seemed pretty proud of that.

    To answer the poll question, I think the EPR effect is pretty wild :surprised !
  5. Jan 1, 2005 #4


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    The axiomatical structure.There's no other science theory with better axiomatization.And of course,the enormous amount of mathematics lying behind it. :!!) Staggering,really... :smile: And just then comes the useful part:the tremendous amount of aplications and the idea of quantization itself which has led to the SM which people over the last 30 years are trying to improve.

  6. Jan 1, 2005 #5
    I like the fact that the wavefunction and the math you do with it doesn't have much of a physical interpretation. Once all the math is done, you square psy, and there's the physics. It's as if the squaring was a gate between complete abstraction and physical sense.
  7. Jan 1, 2005 #6


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    Explaining state reduction through decohearence interests me as well. In paticular:
    Maybe consciousness plays a part in establishing these "preferred" pointer states.
  8. Jan 2, 2005 #7
    ^ but i think so far, every "theory" meant to explain wavefunction collapse have been at best philosophical, at worst, speculative. There seems to be no concrete theory or equations to describe it.
  9. Jan 4, 2005 #8


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    QM is simply the best and broadest theory in physics, that's what interests me. I find it astonishing, for example, that the Schrodinger equation applied to atomic hydrogen gives such an accurate picture (description, if you like), nailing as it does the hydrogen spectra, and, providing at the same time, very clear reasons for the discrete structure of atomic spectra -- bound states and energy conservation. Atomic physics, world class physics indeed. Much of chemistry is based on QM. Virtually all of nuclear and particle physics, including QED, are applications of QM. We have a very deep understanding of the structure of matter, particularly from solid state physics, which is mostly QM.

    From QM we have positrons, neutrinos, Fermi-Dirac and Bose-Einstein distributions, lasers, superconductivity. semiconductors, nuclear decay, the Lamb shift, electron microscopes, ...

    QM is awesome, indeed.

    Reilly Atkinson
  10. Jan 4, 2005 #9
    From the view of general relativity, QM is indeed an interesting theory, but it is not a beautiful theory. You have no a clear logical line to understand it.
    In other word, general relativity or Maxwell theory is somewhat "perfect" theory, QM is far from it.
  11. Jan 4, 2005 #10
    I think QM is beautiful theory just because it dont try to paint a macroscopic picture on the microscopic world.

    I think that the copenhagen interpretation might be the correct one. Eg. where was the electron before we meassured it, it was nowhere! It was the meassurement that forced it to take a stand.

    If there is to be one theory that explains the whole world than that theory cant have an explanation for if it has then its explanation should have been that theory. QM lacks an explanation according to the copenhagen interpretation eg. its the theory that explains the whole world. Ofcourse we dont have the complete knowledge about QM yet since it cant explain everything yet.

    I dont feel that general relativity and maxwells em theory are in anyway better theories than QM, infact I believe them both to be large scale approximations of QM.
  12. Apr 21, 2010 #11
    May be, apart from the other interesting features of QM other people said.
    I find very astonishing the fact that through one of its applications quantum-computing,
    people reveal some universal properties of our Universe- as the connection between
    entropy and information erasure and also are about to harness the ultimate abilities of the
    physical systems to process information.

    Quantum teleportation is another interesting effect, also quantum cryptography, communication...

    I think QM really "shows" us what are the "limits" of in the things that could be done in our Universe!
  13. Apr 21, 2010 #12
    It is physics. Does one need another reason? :!!)
  14. Apr 21, 2010 #13
    When I was younger I used to take everything apart to see how it worked and after taking things apart (the hairdryer, vcr, etc) I was always further confused by what I found inside though I found new toys to play with. I suppose QM is not much different.
  15. Apr 21, 2010 #14


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    Those pointer states are supposed to be stable records of the state of the system. A memory in your brain about the result of a spin measurement is a good example of a stable record of a particle's spin state. So memories can't exist without pointer states, and consciousness can't exist without memories. Therefore, consciousness can't exist without pointer states.

    So it's not like the pointer states are created by consciousness. Instead the interaction Hamiltonian selects the pointer states, and the pointer states define the worlds that can contain conscious observers.
  16. Apr 21, 2010 #15
    I am neither sure, or unsure of quantum mechanics being interesting.
  17. Apr 21, 2010 #16
    why some parts of it seem logical; and, other parts of it seem to be so 'made up' and more based on almost mysticism----and it is considered one theory at the same time
  18. Apr 21, 2010 #17


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    What makes quantum mechanics so interesting?

    a) We still have no idea if the theory actually describes reality or if it's just a set of rules that we can use to calculate probabilities of possibilities.

    b) It's the first theory that assigns non-trivial probabilities (numbers other than 0 and 1) to possible results of experiments.

    c) It's the most accurate theory in the history of science.

    d) I'm with dextercioby about the axioms. They're quite beautiful. There are also several very different ways of stating them. One of them, the quantum logic approach to QM, makes QM look very much like a toy model that someone invented just to show that theories of the type mentioned in b) can exist. Another one, the C*-algebra approach, shows how QM generalizes probability theory. Abelian C*-algebras define classical theories along with the axioms of probability theory, and non-abelian C*-algebras define quantum theories, in which ignorance is not to blame for the appearance of non-trivial probabilities.

    e) All those wonderful experiments, both real experiments and thought experiments: Schrödinger's cat, the double slit experiment, Bell inequality violations, delayed choice experiments, etc.

    f) How QM+Lorentz invariance leads to the concept of particles.

    I could probably go on for a long time, but I don't have all day. :smile:
  19. Apr 21, 2010 #18
    Well it shows that God does play dice with the universe. Hey, who doesn't like a little gambling? :approve:
  20. Apr 21, 2010 #19

    It used to make my parents go crazy when I took stuff apart when I was a kid. I never really knew what I was doing then and not much has changed now. This is especially true for QM. I constantly feel like im in the math dept instead of the physics dept, but that is beacuse I dont know enough yet. And that is what makes it interesting, theres always more!
  21. Apr 21, 2010 #20


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    Yea. I've learned a little in 5 years. Now I've got another stable memory. Thanks :smile:
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