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How and where does a de Broglie wave propagate?

  1. Jun 23, 2011 #1
    I've posted a similar question here before, but to no avail. My question is, what is the cause for the propagation of a matter wave? In the same sense that oscillating electric and magnetic fields carry light across space (for lack of a better explanation), and every wave propagates through a medium of some sort i.e. sound through air, light through spacetime.
    What causes the propagation of a de Broglie wave?
    And what does a de Broglie wave propagate through?
    Also, if one adopts the copenhagen interpretation that this wave represents probability densities, what actually is the cause for this evolution of probabilties? I understand Schrodinger's equation describes this evolution, but as far as I understand it doesn't explain the fundamental root cause for this evolution.

    Also, please don't post any links to Wikipedia articles, there's a reason I come here with these questions after reading these articles.
  2. jcsd
  3. Jun 23, 2011 #2
    de Broglie wave is kind of quantum wave. So there is no similiar understanding of progagation like classic physics.
    The propagation of de Broglie wave would depend on the substance concerned itself. where you can find the possiblity, for example, pariticle , decides on the particle or system containing the particle. besides, there is field effecting the possibility, which could be included in the system in question.
  4. Jun 23, 2011 #3
    But nevertheless, something is causing this wave propagation. What property of matter dictates the existence of a matter wave, or is it just that? Does the wave exist solely due to the existence of matter? I understand that potentials and fields affect the nature of the wave itself, much the same way that a gravitational or electric field affects the motion of a particle in that field, but those fields permeate space and are detectable. If a probability wave is affected by some potential of sorts, then that wave itself must be connected with the fields themselves which permeate space, and therefore must exist in space. If this isn't true, than I clearly have no understanding of the wave-like nature of matter.
  5. Jun 23, 2011 #4
    The official answer is "shut up and calculate". The truth is nobody knows yet.

    Some believe there's no possible answer to your question. This is a remnant of a philosophy called logical positivism which was in vouge at the time of formation of these ideas.

    Others believe there will one day be a definitive answer to your question.
  6. Jun 23, 2011 #5
    de Broglie wave is a probability wave. Take one electron for example, time one (t1) it appears at site one (s1), t2 it does at s2. s1 and s2 have no any inevitable connection. they are randomly decided by quantum mechanics. This is the charateristic of quantum mechanics. So, s1 prapagates to s2 of the de Brogile wave through a random process. as far as media concerned, it depends on the media the experiment does in.
  7. Jun 24, 2011 #6
    what i can say is, when waves glue together it shapes as a particle. if speed of particle is near or almost light, you feel its effect as wave, when it is alot less then light speed, you think, it is a particle. its kinda inside electron, photon stuff and a point where we can't break it. Take it as water, when you freeze it, it is ice (solid matter) and keep heating it is gas. When it is solid where the gas move and when it is gas why it don't hit me hard?
    Mass and wave are two form of matter. But matter always have a composition of both in ratio ( example: Matter ( x% wave, y% mass).
  8. Jun 24, 2011 #7


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  9. Jul 4, 2011 #8
    How come he got banned after 2 posts? Both of his posts are here in this thread and they don't seem offensive yet his name is crossed out.

  10. Jul 4, 2011 #9
    Broglian waves do not propagate in the meaning of "to propagate"

    Your question is exactly as absurd as the received ideas you were taught by. Do not trust the enemies of Louis Victor de Broglie and their heirs to tell you honestly the truth about Broglie's works. Read him directly in french : http://tel.archives-ouvertes.fr/docs/00/04/70/78/PDF/tel-00006807.pdf
    or in his Nobel lecture, in english :

    Broglian waves do not "propagate" more than the electron itself, or any other fermion : they ARE the matter, no more, no less.

    What the rumor propagated by the Copenhagen pack tells you, is that the broglian intrinsic frequency [itex]\nu_e = \frac{m.c^2}{h}[/itex] does not more exist, as Broglie and Schrödinger were defeated by the winning pack. By this trick, no more things remain yet understandable.

    Reasoning as a strict relativist, Broglie worried about how an observer should perceive this intrinsic frequency for a moving electron. Using the properties of the Lorentz transform, he deduced the theorem of Harmony of Phases. Then Broglie deduced that the phase velocity V should be c² / v : [itex]V = \frac{c^2}{v}[/itex]
    So in the frame of the electron, the electron is everywhere in phase with itself, and cannot become punctual, never.
    An unavoidable consequence that Broglie has never perceived, is that every quanton dwells in the noise of the broglian waves of all the others. No screen, no armour-plate for that...
    Last edited: Jul 4, 2011
  11. Jul 4, 2011 #10
    P.S. Louis de Broglie

    Post scriptum : Louis Victor de Broglie
    The Broglie family was from Savoia, exactly the Piemont.
    They came to the service of king of France in 1643, with Francesco Maria Broglia.
    Pronunciation : as english "Broy".
    The "de" is the nobiliar preposition. The francized name remains "Broglie".
    But with the first name or the title, you inject the preposition "de" in between.
    "Ask to Broglie, he must know that", "the duke of Broglie", "le duc de Broglie", "Louis Victor de Broglie", "Did Broglie explain to you the driving of the guns, Lady ?".

    The word "broglium" existed in gallic, and survives in toponymy, but I do not know whether it is related with the family name "Broglia".
  12. Jul 4, 2011 #11
    Well, unfortunately some of us must suffer the drawbacks of reading de Broglie in English ;^)

    It is true that in deference to the generally fuzzily conceived mantra of particle-wave duality by the QM community, de Broglie very definitely said that the wave is associated with the particle. Or to put it more plainly: the wave co-exists with the particle.

    If de Broglie was right then there is no need for the wave associated with an electron to be any different at all from the wave associated with a photon, for instance. It's all the same energy fluctuating in response to the fields associated with the transit through space of different particle species.

    Wow, this is a wild thread! (I love it ;^)
    Last edited: Jul 4, 2011
  13. Jul 4, 2011 #12
    What is terrific in the biography of Louis de Broglie, is that he went astray very soon, dreaming to keep the position coordinates and the idea of corpuscle he had learned in the classroom. Alas both the idea of corpuscle, and the idea of position coordinates belong to the macroscopic world, and cannot be extrapolated to quantons.
    So he put aside for years his first idea, the great one : the intrinsic frequency [itex]\nu_e = \frac{m.c^2}{h}[/itex].

    No, there is no such thing as "fluctuating energy". Electrons are fermion waves, with spin 1/2 and charge -1, and the relevant equation is Dirac's one, at least for moderate energies.
    Last edited: Jul 4, 2011
  14. Jul 4, 2011 #13
    That may well be, but we might consider the underlying reason why that would be the case...

    Hmmm, possibly. However, Sir J. J. Thomson (who was Langevin's mentor who was de Broglie's mentor) succeeded in deriving de Broglie's results from purely physical reasoning whereas de Broglie arrived at his result from analytical reasoning. Thomson's reasoning, which involved "fluctuating energy", can be rectified with both classical and QM paradigms whereas I'm not sure you can say the same about what you're saying.
  15. Jul 4, 2011 #14
    So he put aside for years his first idea, the great one : the intrinsic frequency [itex]\nu_e = \frac{m.c^2}{h}[/itex].
    Louis Victor was an extremely timid and polite man. He carried a terrible internal persecutor.
  16. Jul 5, 2011 #15

    That should work for any particle having mass, shouldn't it? For instance:

    [tex]\nu_e = \frac{m_e c^2}{h} \ \ \ \ \ \ \ \
    \nu_p = \frac{m_p c^2}{h} \ \ \ \ \ \ \ \
    \nu_\mu = \frac{m_\mu c^2}{h}[/tex]

    for the electron, proton and muon
    Last edited: Jul 5, 2011
  17. Jul 5, 2011 #16
    Dirac-Schrödinger electromagnetic periodicity, too.

    Sure !
    For brevity sake, I did not mention here that though the Broglie periodicity is enough for explaining the interference of a fermion (spin 1/2) with itself, when the fermion interacts with an electromagnetic field, one has to use the electromagnetic frequency of the Zitterbewegung, discovered in 1930 by Erwin Schrödinger on the basis of the Dirac's wave equation of the electron. And it is the double : [tex]\nu_{e_{Dirac-Schroedinger}} = \frac{2m_e c^2}{h} = 2,4712 . 10^{20} Hz[/tex]

    For instance, when in 1927 Schrödinger tried to explain the Compton scattering by the Bragg law of diffraction, he missed the point : with the broglian equidistance, the only one known in 1927, he could only reach the order two of diffraction, though the order one was never observed. But all is okay when considering the stationnary wave at the Dirac-Schrödinger wavelength, due to the beat of waves between incoming and departing electron. Links :
    E. Schrödinger. Über den Comptoneffect. Annalen der Physik. IV. Folge, 62. http://www.apocalyptism.ru/Compton-Schrodinger.htm

    See also the annihilation of a pair e+ e- into a pair of gammas,
    and the materialization of a gamma over 1022 keV into a pair e+ e- when hitting a bonded electron.
    Last edited: Jul 5, 2011
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