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Why do a lot of senior physics majors struggle with quantum mechanics?

  1. May 6, 2008 #1
    How much will linear algebra helped you with quantum mechanics? How difficult is quantum mechanics compared to the rest of the physics courses you take as a physics majors. Do most of you struggle with grasping the new intuitive concepts like probability dominating determinism rather than the mathematical aspects of quantum mechanics.

    Tell me what will I expect from this course. Because I do not have a problem understanding that their are a different set of physical laws for the macroscopic universe and the subatomic realm. I do not see why quantum mechanics for senior physics majors would be so difficult compared to classical mechanics and electrodynamics
  2. jcsd
  3. May 6, 2008 #2
    Inadequate mathematical preparation. There are also a number of different views as to the ideal ordering of topics so as not to confuse students further. There's also the issue of it being a wee bit counterintuitive at first, but that goes away quickly (or not).
  4. May 6, 2008 #3
    What would be adequate mathematical preparation? By the time I take QM 1 I should have taken: Calculus 1-3, Differential Equations, Abstract Vector Spaces (basically a rigorous linear algebra class since they teach us LA in Calc 2), and Complex Analysis, and I will be taking Partial Differential Equations 1 and Differential Geometry at the same time as QM. Would this be adequate preparation or should I try to fit in more (or different) math by then?
  5. May 6, 2008 #4
    Hell if I know, but people seemed to have a lot of trouble with the math. I only had a year of calculus, and I thought the quantum stuff was pretty easy.
  6. May 6, 2008 #5
    I'd say your fine Monocles.
  7. May 6, 2008 #6


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    Your math preparation seems fine. I'm currently in a quantum course, and I can say you have all the math needed to do what we covered. Not having to teach yourself the math as you go along will make a big difference in how the course goes.
  8. May 6, 2008 #7
    what math would you need for QM? Do you really to learn differential geometry
  9. May 6, 2008 #8


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    No, for a course using e.g. Sakurai you need a good understanding of the basics of linear algebra+the "usual" math used in other courses (differential equations etc). Thats it.
    Linear algebra is really the key. QM is probably the only physics course where ALL the linear algebra you learned in your math courses is actually used.

    My problem was that I took both linear algebra courses year 1 and the "real" QM course 4 years later (this was in Sweden, I spent 5 years at university) and I had actually forgotten much of the linear algebra by then.
  10. May 6, 2008 #9
    Linear algebra is the important math that you need. That is linear algebra done abstractly, and not just matrix manipulations. The thing is that the really important math is Weyl's contribution to qm-- group representation theory which is usually covered in abstract/modern algebra instead of linear algebra.

    And what if you don't have that background? Then you just won't appreciate the underlying mathematical structure of the theory, but you'll still learn the material and be able to calculate things and understand the physical concepts, it's not the end of the world.
  11. Jan 9, 2009 #10
    i dont think its the mathematics that is the problem, that side of it has never bothered me but i've only just finished my first semester of quantum mechanics and its the hardest thing i've ever done. i have certainly been confused by a lot of it. I'm trying to sort it out now though, i think its just a matter of it taking time to sink in, which it definitely is after some revision. I remember it took a while for things to finally click when i first started learning classical physics in school, one day everything just falls into place though.
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