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Waves of what

  1. Mar 31, 2012 #1
    i m studin the quantum mechanics in my second semester. Though i am doing an engg degree but i have deep intrest in physics from my high school days. That is the reason i want to grab every why and how of physics.

    Shrodinger equations say that every particle has wave asscociated with it. I can well understand this. Then i read the topic called 'waves of what'. Shrodinger said that these are waves of propability. I can understand this waves of propability when shrodingers equations are applied to electron of hydrogen atom but i couldnt imagine light as waves of probability as light are electromagnetic waves and photons are particles. So where are the waves of probability of light?

    I couldnt find the answer to this question in my book. Any explanation would be helpfull
  2. jcsd
  3. Apr 2, 2012 #2
    Yes all atomic scale particles are waves of possibilities including photons (the complete electromagnetic spectrum ie: radio waves, x rays, gamma rays, light rays).

    What you should be asking is on 'what' do the waves travel on when they go through the vacuum of space(thought for many years to be completely empty). =)
  4. Apr 2, 2012 #3
    The magnitude of electromagnetic wave can consider as the magnitude of amplitude of probability wave of photons.
  5. Apr 7, 2012 #4
    are you saying that photons are responsible for electric and magnetic field in EMWs. Can photons generate electric/magnetic field? It is a chargeless particle.
  6. Apr 8, 2012 #5
    photons are electromagnet fields.
  7. Apr 8, 2012 #6
    Rather EMR is made from photons.
  8. Apr 8, 2012 #7
    All atomic particles are waves of possibilities, Schrodinger's work is centralized around the wave-functions and wave-like properties of subatomic particles. I suggest looking into the work of Louis de Broglie if you're really interested in things like this. :)
  9. Apr 9, 2012 #8

    Firstly, you don't have to apply wavefunctions to macroscopic waves of light. They're simply too large, the effects of quantum mechanics are most notable at subatomic scales. We're more concerned with the photons comprising the light.

    Remember, in quantum mechanics, you can never think of an individual particle, such as a photon, like a particle or a wave. The Heisenberg Uncertainty Principle states that there is an inverse relationship between your knowledge of position and momentum, so that particles have a strange 'wave-particle duality', according to the Copenhagen Interpretation.

    You can think of the photon as taking several paths at once, most centered around the most probable region of finding located. This makes up, and evolves like, a wave. A probability wave, known in the field as a wavefunction.
  10. Apr 9, 2012 #9
  11. Apr 10, 2012 #10
    Thanks for the link goodison_lad. That helped a lot.

    So Light are photons. And just like every particle its has position-momentum uncertainity and hence have its wave of probability. The Electric and Magnetic fields are property of photons only. And photons are simple particles only. The reason why they cant travel below speed of light is because of there zero rest mass. The property of generating Elecric and Magnetic field makes them force carriers. And light is similar to other force carriers like the strong and weak force particles.

    That is what i am getting is that right?
  12. Apr 10, 2012 #11
    Think so, except it's not similar to all other force carriers. Gluons I'll ignore for the time being. The W and Z bosons, plus mesons, are what I'm thinking about. Some mesons are actually considered force carriers of extensions of the fundamental force. Anyways, these mesons and W and Z bosons do not have no rest mass, and thus do not move at c.
  13. Apr 10, 2012 #12


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    aren't waves and particles just platonic concepts like triangles and cubes, abstractions that do not really exist other than conceptually? (i.e. as defined by geometry, no squares exist in the universe)

    the concept of wave comes from water waves and other movements of energy through a medium - which is why everyone thought there had to be an ether to propagate EM waves back in the 19th century, but why should EM waves in space be exactly analogous to water waves, even if they share some common characteristics like diffraction?

    the concept of a particle is totally platonic - its just an abstraction

    if the characteristics of quanta as described by QM is reality, why worry about preconceived definitions or particles or waves?
    Last edited: Apr 10, 2012
  14. Apr 10, 2012 #13
    All physical concepts are abstractions: whether or not 'reality' is really exactly like a physics model can never be answered and the question might have no meaning. Einstein said "The most incomprehensible thing about the world is that it is comprehensible", and was always amazed that humans were able to come up with anything at all that appeared to describe how Nature works.

    All we can say is whether a theory we construct leads to testable predictions. If it does, and the predictions are verified, we adopt it as a good theory. If not, we either modify it or abandon it. Ultimately all we can say is that certain phenomena behave as if they are these things we've previously identified and described as waves, while others behave as if they are things we have previously identified and described as particles.

    As for the 'reality' of electron waves or the like, most physicists are content to just let the maths do the talking. This goes for a lot in quantuim mechanics, summarised by David Mermin's statement 'shut up and calculate'.
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