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Are electrons wave or a particle?

  1. Sep 21, 2003 #1
    Are electrons wave or a particle???

    dear reader,
    i have an interesting question. Are electrons waves or particle? Electrons act as a particle when electricity passes through a conductor but according to quantum physics electrons are waves, if you do the two slit experiment with electrons the result will be that electrons are waves.

    -benzun

    If i am wrong please let me know.
    :wink:
     
    Last edited: Sep 28, 2003
  2. jcsd
  3. Sep 21, 2003 #2
    It's not a question of "or".

    We simply lack the ordinary frame of reference for dealing with subatomic particles.
     
  4. Sep 21, 2003 #3

    Janus

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    Like anything else in the sub-atomic world, electrons are neither waves or particles in the truest sense, but display the properties of both, just as photons do. Most of the time we see the particle type aspects of the electron more readily because its associated wavelength is so small.
     
  5. Sep 21, 2003 #4
    I almost shutter to answer this question, but:

    Electrons behave in both ways, but what we see depends on the experiment, and what we are looking for. When Experiments are testing and look for a wave nature they find it, and when they look for a particle nature they find it. This should be very distrubing on the surface because it means that the results of an experiment are in a way altered by our preconceived notions of what should be, not governed by what is. It is odd, but nevertheless a well established nature of the subatomic world.
     
  6. Sep 22, 2003 #5
    This is only one (but presently the most common) interpretation of the particle/wave phenomenon.

    According to Louis de Broglie an elementary particle is a particle in the true sense. But it has a wave around it, called the piloting wave. This wave guides the particle and causes the effects like the scattering at a double slit. The wave is caused by the internal oscillations of every elementary particle. (De Broglie received the Nobel price in 1929 for his detection of the wave behaviour of particles).

    Bohr and Heisenberg have - as we know - refused this interpretation. John Bell has investigated the available literature about it and has stated in his book "Speakable and Unspeakable in Quantum Mechanics" that he never found any arguments used by Bohr or Heisenberg, why the approach of de Broglie would not be possible. De Broglie's position was just ignored by both, and still it is by the majority of the physical community.

    According to John Bell there is no argument which would refute the opinion of de Broglie. The advantage if this approach is that it is very easy to understand, and it takes the mystery away from quantum mechanics.
     
  7. Sep 22, 2003 #6

    jimmy p

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    Electrons and Photons follow a theory called wave-particle duality, where as they are classically viewed as either a wave or a particle, they share characteristics of both. Electrons display wave properties because their exact position cannot ever be determined but there is an area in which they could exist. The only way to determine how they work is by giving them a wavelength. Likewise with photons, which are said to have particle properties to explain the photoelectric effect.
     
  8. Sep 22, 2003 #7
    But, as I wrote, this is only one of the existing theories. According to de Broglie, Einstein, Bell etc. it is different.

    If we measure the position of an electron, we measure in fact the position, the frequency, and the phase of the wave. We know (also from radio technology) that we have to measure a high frequency signal for a sufficiently long time to know exactly it's parameters. It is the same when measuring the electron's wave. The uncertainty of the measurement of the wave results in an uncertainty about the position of the particle. That exactly is what Heisenberg's uncertainty rule says.

    So, the position of the electron is not uncertain, but our knowledge of it is.
     
  9. Sep 22, 2003 #8

    FZ+

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    IIRC, what you are referring to is the Debroglie-Bohm interpretation. In other words, what debroglie-bohm postulate is the existence of non-local hidden variables. Yes, there is no current way to rule this out, but there is no way to rule it in either. The interpretation is also in serious conflict with relativity over FTL information transmission, so most put it on the shelf.

    Very easy to understand does not always equal true.
     
  10. Sep 22, 2003 #9

    ahrkron

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    "Wave-particle duality" is the name given to a property of the behavior of atomic phenomena.

    The "theory" is QM, not "wave-particle duality".

    Maybe you meant that there are different interpretations for the formalism, which is true.

    Also, it is fair to say that the majority of physicists favor the interpretation that the position of the electron is indeed undetermined until measurement. It is not a matter of our knowledge of it.
     
  11. Sep 23, 2003 #10
    The interpretation as I gave it is in no conflict with relativity.

    From the Dirac function of the electron it follows that the inside of the electron oscillates (i.e. it orbits) with c. If this is true then the field which keeps the electron together will be an alternating field. This field propagates with c into all directions. If the electron moves towards a double slit the field builds necessarily an interference pattern. This pattern guides the constituents of the electron through the slit. If the electron is now registered behind the slit, then the experimenter will see the interference result and he has the impression that the electron is a wave.

    The process described above is not a mere possibility but a necessity. And there are no hidden variables involved into this process.

    To my knowledge no one has ever argued in detail that this will not happen.

    Please refer to John Bell for the literature situation.
     
    Last edited: Sep 23, 2003
  12. Sep 23, 2003 #11

    FZ+

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    In that case, this would be in direct contravention of the results of the Aspect experiment.
     
  13. Sep 23, 2003 #12
    The best description I know of about what an electron is, which is to say how it behaves, is one of the Feynman Lectures titled Bullets and Waves. It's a must read if you want to understand quantum mechanics and the behavior of electrons.
     
  14. Sep 23, 2003 #13
    Thanks Albrecht for bringing up de Broglie. Very interesting and logic.

    FZ+, can you explain why this is contradicting Alain Aspect's Experiment?
     
  15. Sep 24, 2003 #14
    As part of my case for a Single (Vacuum) Force Theory I made notes on a new interpretatation of The Quantum Hall Effect and showed a relationship between the vacuum wave and the electromagnetic wave. I have never received any comment on this page.
    As it explains the relationship between wave and particle perhaps someone would make a comment. (Go to my home page via the 'Members List')
     
  16. Sep 24, 2003 #15

    FZ+

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    As part of the aspect experiment, a change in the experimental setup is made while the photons are en route, such that the only way any information can be transmitted from the site of the change to influence the polarisation of the photon is by breaking the c limit. Yet the results obtained still somehow show the same violations as predicted by QM.

    The result of this is that either the hidden variables are non-local, and thus break the light barrier, or they don't exist at all. If the field that guides the photons propogates at c, there is no way in which the change can influence the photon, which is outside it's light cone.

    On the other hand, there are some loopholes, but they are tight ones.
     
    Last edited: Sep 24, 2003
  17. Sep 24, 2003 #16
    Every field we know in physics propagates at the speed of of light c.

    The field which is caused by the electron propagates at the same speed. There is nothing special about it.

    Something must be severely mixed here.

    The Aspect experiment is about entangled photons. That is a completely different case.

    Thank you, pelastration, for your comment. De Broglie is by my understanding one of the greatest physicists of the 20th century. Many physicists are not aware of this.
     
  18. Sep 24, 2003 #17

    FZ+

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    How is it different? If we follow the hypothesis that the electrons, and photons are existent as discrete particles guided by a field, the only option to allow the entangled spooky action at a distance effect is to make the field a non-local variable in the motion of the particle. Else, we would be forced to imply the conventional uncertain state of the particle to account for this phenomena, which would then render the existence of a field superfluous.
     
  19. Sep 24, 2003 #18

    jcsd

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    Bohmian Mechaincs is in conflict with relativity as the quantum potential can affect particles non-locally which for a filed would be forbidden by relativity.
     
  20. Sep 25, 2003 #19
    Bohm's interpretation does violate relativity indeed (as it is conceived today) but not because it implies an instantaneous transfer of information.This happens because the quantum potential constitutes an absolute system of reference,something expressly forbidden by relativity.In Bohm's 'pilot-wave' interpretation the quantum potential is seen as pervading all space,local changes in the state of a quantum particle provoking the instantaneous change of the quantum potential in the whole of space.This does not imply an instantaneous transfer of information any more than the 'intrinsic' nonlocality assumed by the usual Copenhagenist approach (the pair of entangled particles form a single 'object',their wavefunction being spread over space).

    Anyway we must never forget that relativity cannot even be accomodated theoretically with the standard formalism of QM.Finally since the experiment remain the 'highest authority' there is no sufficient reason to rule out de Broglie-Bohm pilot-wave' interpretation [it is equally supported by all existing experiments as the copenhagenist interpretation of QM] in spite of the preferential frame problem [yes Michelson Morley's experiment does not rule out the possible existence of an aether interacting very faintly with the macroscopic level,as the quantum potential is].
     
    Last edited: Sep 25, 2003
  21. Sep 25, 2003 #20

    jcsd

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    Yes relativtly as a whole cannot be accomadated with QM but special relativity can be accomadetd with QM which means that Bohmian mechanics must be rejected in relativistic quantum mechanics.

    Also the matter-wave interpretation would predict that a single atom would have a dipole as the electron has a definte postion within the atom however there is no dipole observed in a single atom.
     
  22. Sep 25, 2003 #21

    This is not enough to rule out Bohm's interpretation,in fact,from what I've read,there is underway a very serious research in order to make bohmian mechanics relativistic (of course not totally compatible with all postulates of relativity as it is now).



    From all I've read so far Bohm's interpretation makes exactly the same predictions as the Copenhagen Interpretation,there is no experiment,as of now,which to make the difference between them (not a big surprise given that both have at base the same mathematical formalism).

    There were some claims,on the net,that Bohm's theory make some different predictions and therefore there is a way to make the difference between copenhagenism and bohmian mechanics.The claims went further,that Bohmian mechanics was falsified but from what I've read there is no real base for the claim that copenhagenism and bohmian mechanics really make different predictions.

    There is an objection to bohmian mechanics here for,indeed,it cannot explain in a satisfactory manner (from all I know at least) why a electron (considered as being only particle) do not fall in the nucleus.However this is not enough,the existence of some unexplained yet phenomena never count as a disproof of a certain theory.
     
    Last edited: Sep 25, 2003
  23. Sep 25, 2003 #22
    More exactly the objection to Bohm's interpretation mentioned in my above post is that for some orbitals,for example those in the state with n=2,'p' and so on which do not have spherical symmetry,the electrons are in fact accelerating and should radiate away energy.Or this is against the postulate stating that they do not radiate energy when being in an allowed stationary orbit.However this does not mean there is no valid explanation,though many disagree with it.As Vigier has proposed maybe electrons do radiate energy in fact only that the energy loss is negligeable,the wavelength of this radiation being extremely large.I find this argument fair enough,well beyond an ad hoc explanation,anyway 'working' for all our actual practical purposes.Indeed it is fully compatible with Bohr's postulate the latter being an idealized case of Vigier's proposal.
     
    Last edited: Sep 25, 2003
  24. Sep 25, 2003 #23
    The idea that the electron (like the other elementary particles) is a real particle, which is guided by the field which is caused by it's internal forces, has not much to do with Bohm's quantum mechanics. And it is of course not in conflict with relativity. The field propagates with c, which is standard for relativity.

    It is one electron at a time which is guided by it's own field. So there are no entangled pairs of particles.

    This is very classical and it works perfect to explain the interference at a double slit.

    De Broglie explained all this in his famous papers of 1923 and 1924, and he receive the Nobel price for it. I do not know of any serious arguments against this explanation.
     
  25. Sep 25, 2003 #24

    jcsd

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    Albercht there are many serious ontological arguments against Bohm's interpretation which is the reason that it is not the standard interpretation, mainly that it is a non-local realist theory and thus in conflict with relativity (of course others that centre around the nature of the quantum potential).
     
  26. Sep 26, 2003 #25
    de Broglie and kirilyuk

    Andrei Kirilyuk has focused on deBroglie. I believe you need to read some of his publications when you discuss a de Broglie piloting wave.


    http://arxiv.org/pdf/quant-ph/9911107

    ABSTRACT. A physically real wave associated to any moving particle and propagating in a
    surrounding material medium was introduced by Louis de Broglie in a series of short notes in 1923 and
    in the most complete form in his thesis defended in Paris on the 25th November 1924. This result,
    recognised by the Nobel Prize in 1929, gave rise to the whole field of the ‘new physics’ known today as
    ‘quantum mechanics’. However, although such notions as ‘de Broglie wavelength’ and ‘wave-particle
    duality’ have become ‘conventional’ in the standard quantum theory, it actually only takes for granted
    (postulates) the formula for the wavelength (similar to other its formally postulated ‘results’) and totally
    ignores the underlying causal, physically real and transparent picture of quantum/wave behaviour
    outlined by Louis de Broglie in his thesis and further considerably developed in his later works, in the
    form of ‘double solution’ and ‘hidden thermodynamics’ concepts (the first of them is only
    mechanistically imitated within the over-simplified ‘interpretation’ of ‘Bohmian mechanics’, now often
    presented as ‘causal de Broglie-Bohm theory’). The payment for such crude deviation from the basic de
    Broglian realism is the absolute domination of the fundamental science by purely abstract, detached from
    reality and mechanistically simplified schemes made of formal symbols and rules that has inevitably led it
    into the deep impasse judiciously described today as the ‘end of science’. However, an independent
    approach of the ‘quantum field mechanics’ (quant-ph/9902015,16, gr-qc/9906077) created recently
    within the ‘universal science of complexity’ and the related ‘dynamic redundance paradigm’
    (physics/9806002) leads to confirmation and natural completion of unreduced de Broglie's results
    eliminating all their ‘difficult points’ and reconstituting the causally complete, totally adequate and
    naturally unified picture of the objective reality directly extendible to all higher levels of the complex
    world dynamics.

    Kirilyuk: http://arxiv.org/pdf/quant-ph/0101129

    We have demonstrated, in the previous section, how the Schrödinger equation and the causally
    extended wavefunction naturally emerge from the unreduced analysis of the interaction process in the
    simple, a priori homogeneous system of two coupled protofields.
    ---
    pag: 32
    It is important to emphasize that the obtained generalisation is not a formal mathematical
    generalisation of the particular equations. As we have shown above, the Schrödinger equation describing
    system complexity development at its certain level is causally derived from the unreduced analysis of
    interaction between entities of lower level(s), which always includes the dynamic redundance and
    entanglement phenomena totally absent in the canonical science that simply postulates, in each particular
    case, the ‘suitable’ mathematical form of the main dynamic equation and tries to fit its severely limited,
    dynamically single-valued solutions to the observation results. This blind trial-and-error search and purely
    technical tricks of the conventional empiricism lead to the abuse of ‘mysteries’ and abstraction at the
    lowest complexity levels of the unified world dynamics and to practical absence of any objective
    description for higher levels of complexity, where the number of necessary ‘postulates’ grows
    dramatically, in proportion to realisation number determining the system complexity. The unreduced
    derivation and complex-dynamical interpretation of the universal Schrödinger formalism provide, in
    particular, the inherent creativity and dynamic adaptability for the emerging structures that make them
    realistically ‘alive’/self-developing, while being totally absent in the dynamically single-valued projections
    of the canonical science, they should be artificially added to them within that approach in an inevitably
    incomplete form.

    All arXiv's of Andrei Kirilyuk : http://arxiv.org/find/physics/1/au:+Kirilyuk_A/0/1/0/all/0/1

    ---
    To me Kirilyuk's protofields is like several spacetime layers which interact.
    Layered spacetime is created by self-penetrating unbreakable Brane.
    On those local spots spacetime is multi-layered: so concentrated, more dense and less elastic.
    Multi-layers create local internal friction which brings thermodynamics, EM, etc.
    The brane acts as gravity. Everything is interconnected.
    This approach fits in de Broglie's approach.

    Dirk
     
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