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Wavefunction is compex

  1. Mar 1, 2014 #1
    hi, please explain why do we need complex wavefunction in quantum mechanics?
  2. jcsd
  3. Mar 1, 2014 #2


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    Interference. Complex amplitudes are necessary to produce interference.
  4. Mar 1, 2014 #3


    Staff: Mentor

  5. Mar 2, 2014 #4
    Unless there is an specific reason to assume a quantity is real one should assume it might be complex. Arbitrarily Setting it to be real would've been an unwarranted unnecessary restriction.
  6. Mar 2, 2014 #5


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    That is surely one of the oddest philosophies I've ever heard. I would say quite the opposite. Nowhere in classical physics are complex numbers required. It is only when we come to Quantum Mechanics that they become indispensable.
  7. Mar 2, 2014 #6
    Hi wazi...not to worry, as already noted, it is NOT obvious why such a model works.

    I like the discussion from Bhobba's link, especially:

    A directly observable effect of superposition is interference peaks, say from an electron wave in a double-slit experiment. The superposition principle is what allows us to model the quantum interference which we observe and also the so-called entanglement of quantum states. It is so far thought quantum states are themselves superpositions, or coherent mixtures, of other states. It models what we can observe. In a physical sense, the math explains what we observe, not precisely why.

    But is there a chink in this armor? Something seems awry since QM so far does not seem to model things at below Planck scale. So maybe we are missing some representation? That's a realm of quantum gravity...

    Brian Greene:

    Roger Penrose made comments which correlate nicely with much of Bhobba's link.....

    The following quote is from Roger Penrose [the mathematical physicist] celebrating Stephen Hawking’s 60th birthday in 1993 at Cambridge England.....he was addressing the elite of the physics world.....

    It is also helpful to note we do not actually observe [detect] waves [the fields of opur models]. We observe the local excitations of such wave representations as the point particles of the standard model of particle physics.
  8. Mar 2, 2014 #7


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    physics of waves! :approve:
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