Are electrons wave or a particle???

[benzun_1999]

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.
[;)]

[I, Brian]

It's not a question of "or".

We simply lack the ordinary frame of reference for dealing with subatomic particles.

[Janus]

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.

[VBPhysics]

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.

[Albrecht]

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.

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.

[jimmy p]

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.

[Albrecht]

Electrons and Photons follow a theory called wave-particle duality ...
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.

[FZ+]

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.

[ahrkron]

"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.

[Albrecht]

The interpretation is also in serious conflict with relativity over FTL information transmission, so most put it on the shelf.

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.

[FZ+]

This field propagates with c into all directions.
In that case, this would be in direct contravention of the results of the Aspect experiment.

[Tyger]

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.

[pelastration]

Thanks Albrecht for bringing up de Broglie. Very interesting and logic.

FZ+, can you explain why this is contradicting Alain Aspect's Experiment?

[elas]

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')

[FZ+]

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.

[Albrecht]

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.

[FZ+]

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

[jcsd]

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.

[metacristi]

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].

[jcsd]

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.

[metacristi]

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.


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).


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.


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.

[metacristi]

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.

[Albrecht]

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.

[jcsd]

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).

[pelastration]

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

[metacristi]

jcsd

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).


It's not so simple,what ontological arguments?We do not have direct access at quantum level,so that we cannot directly 'probe' the quantum level,consequently there is no directly 'observed' ontology to attach to the standard formalism of QM.All we can do is to interpret the standard mathematical formalism by attaching an ontology compatible (having explanatory power too not merely being neutral) with all observed facts (experiments) we can reliable observe (indirect observations as in Rutherford's experiment are accepted).This is exactly what the different valid interpretations do,they all make exactly the same predictions,the ontology assigned is interpretation related.

Are they capable to explain all such phenomena in a compelling manner which to make a clear difference between them?I'm afraid not.The reality is that all interpretations have problems,the Copenhagen Interpretation included.How is the operational-positivistic approach advocated by the Copenhagen Interpretation 'forced upon us' as some claim?We can hardly see its proposals as proposing an ontology for the quantum level.Why should the universe suffer a sudden change when the wavefunction collapse?How is Bohr's answer to EPR relevant (the observed and the observer are a single entity) to the quantum entanglement?This is only an 'intrinsic' explanation that many finds hardly satisfactory.That's why there are so many scientists who keep trying...

In fact only the standard mathematical formalism makes predictions that are consistently 'confirmed' practically and this is enough for all our practical purposes.There are many scientists who do not put too much faith in the usual ontologies assigned,they advocate the so called 'shut up and calculate' interpretation.At least for the moment.

Even if we accepted that the Copenhagen Interpretation is really superior to all other (but I don't think is the case) we simply do not have sufficient arguments to claim that it is true or the best interpretation possible.It is even possible that all existing interpretations are far from the ontological reality.

The explanation for the success of the Copenhagen Interpretation has a historical and a pragmatic aspect.It was the first succesfull interpretation and in the same time the simplest (given that it hardly propose an ontology).Had de Broglie not gave up so easily his 'pilot-wave' intepretation of 1926 due to Born's objections maybe the causal interpretation would have won the battle,who knows?

Basically his interpretation is the same as Bohm's approach,but there are some differences regarding the nature of the particle and of the associated wave (distinct entities):in de Broglie's approach there exist only fields,particles being points of high intensity,whilst in Bohm's approach particles are distinct from the fields (classical and the non local quantum potential).

Unfortunately de Broglie did not pursue his work so that the 'fathers' of Copenhagen Interpretation claimed victory,'crowning' it as perpetual winner by making also the bold claim that there cannot exist a better interpretation.

The next generations of scientists grew in this atmosphere dominated by the positivistic approach,including it's 'final' claims.It was not a big surprise therefore that Bohm's attempt (and later Everett's) was meet with manifest hostility.

Bell (a supporter of hidden-variables interpretations himself) even wrote once that his generation was 'brain-shawed' with the finalistic claims that the copenhagen interpretation is the only reasonable interpretation,that Von Neumann proved the physical impossibility of hidden variables and so on.Only in the past 15-20 years have alternative interpretations began to be regarded with attention by the Establishment.There are now much more scientists who ceased to believe in the mith of the Copenhagen Interpretation,quantum electrodynamics is simply not enough,indeed the future might be full of surprises...

[jcsd]

I'll have to go out and play football now, but when I get back my QM textbook has a detailed explanation of Bohmian mechanics along with the reasons why it is rejected as the convential interpretation.

[Albrecht]

Albercht there are many serious ontological arguments against Bohm's interpretation which is the reason that it is not the standard interpretation
How often shall I repeat that I do not present here the theory of Bohm?

What I have explained is what de Broglie and Dirac have said about particles in general and about the electron as a special case.

That is all quite simple. I do not repeat what I have written in the previous post.

Who did have the crazy idea to refer to Bohm when I explained the particle wave approach of de Broglie???

I thank everybody for the detailed information about de Broglie, who was one of the greatest (by my opinion). I shall come back to those threats tomorrow.

[jcsd]

Albrecht the reson why Bohm get's mentioned as soon as you mention De Broglie is that he devolped the theory into the QM interpretation it is today and matter waves are often called De Broglie-Bohm waves.

[Albrecht]

matter waves are often called DeBroglie-Bohm waves
The problem seems to me that the "Copenhagen Interpretation" is so dominant in this time that all alternatives are treated like one single alternative theory.

I have refered to the original idea of deBroglie and I used the Dirac function of the electron. However, I also use the actual results of particle physics which were not known by both. And further the causes of relativity which were not treated by Einstein, but give us a lot of additional information. I have put this together in a web site www.ag-physics.org/structure (http://www.ag-physics.org/structure)

Thank you, pelastration, for your link to the work of Andrei Kirilyuk. The summary looks interesting. Also thanks to you, metacristi, for the informations given.

[jcsd]

De Broglie and Bohm's interpretation is treated as one as Bohm built on De Broglie's work and gave it a more rigourous framework, there are other realist theories that are simlair to Bohm's.

[pmb]

Originally posted by benzun_1999
dear reader,
i have a ineresting question. Are electrons waves or particle? Electrons act as a particle when electricity passes through a conductor and basically have studied electrons as a particle 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.
[;)]

The most accurate answer is that they are neither.

Pete

[elas]

Surely they are both, the particle is bound, the wave extends by influence, to infinity.

[tribdog]

Are electrons waves or particles?

answer #1: Yes
answer #2: Depends on if you're looking
answer #3: Why stop with electrons? photons, protons, neutrons, positrons, quarks, maybe even certain physicist's cats lead a life of duality. Maybe I do when I close my eyes and there's no one else around

[Albrecht]

Again, electrons - like all other elementary particles - are, according to de Broglie, particles. The particles are surrounded by waves which are caused by the field of the circling charges within the particle. These charges cause the force which keep the particle together.

The surrounding waves cause the interference field at a double slit and guide the particle through the slit. They give the impression that the particle is a wave.

If somebody knows an experiment which contradicts this description, please tell us. John Bell at least stated that he did not meet arguments against the presented model of a pilot wave.

Bohm is not a good reference for this question because he had a different goal. His primary goal was to find a deterministic wave function, it was not to resolve the particle wave problem.

[FZ+]

John Bell at least stated that he did not meet arguments against the presented model of a pilot wave.
John Bell did not conduct the experiments which violated the Bell inequalities, which he calculated to be required by any local realistic theory.

[Albrecht]

John Bell did not conduct the experiments which violated the Bell inequalities
Bell's inequalities concern entangled pairs of particles.

The pilot wave explanation for the particle-wave phenomenon has really nothing to do with this.

Of course Bell was aware of all experiments relevant for this case.

[ahrkron]

Originally posted by Albrecht
The particles are surrounded by waves which are caused by the field of the circling charges within the particle. These charges cause the force which keep the particle together.

"Circulating charges withing the particle"?
Not in mainstream physics.

"Elementary particles" are, by definition, the building blocks. They have no "circulating charges" within them.

The surrounding waves cause the interference field at a double slit and guide the particle through the slit.

Composite particles (like protons, neutrons, pions, etc.) do have components, but the electric field of such components should not be confused with the quantum-mechanical wave referred to by Schroedinger's equation.

Otherwise, non-composite particles (electrons, muons, taus, neutrinos and quarks) would not show a wave-like behavior, and they all do.

[jcsd]

Originally posted by Albrecht
Bell's inequalities concern entangled pairs of particles.

The pilot wave explanation for the particle-wave phenomenon has really nothing to do with this.

Of course Bell was aware of all experiments relevant for this case.

Bohm's explanation necessarily also ex[plain quantum entanglemnt if it is to be any use and infact papers on intepreting q. entanglment using the Bohmian model have been written.

The pilot wave doesn't violate Bell's inequality as it is a non-local hidden variables theory.

[christench]

The answer to the question is.........'wave'
Classical physics occurs as an asymptotic limit in the 'wave' model.

But this is only a model. We are physicists. Our job is to model nature. The 'wave' has been defined by us. It is not reality.

I personaly have no idea about the true nature of the elctron, and I dont think anyone does. But I can calculate its energy levels given some simple potentials. I can write a computer program to compute energy in more complex potentials. But all I am doing is applying a model. And to do it I solve Schrodingers 'wave' equation.

Of course when we measure some property of the electron, we only ask classical questions of it, like what is its position or momentum? We dont measure the 'wave' function (although that might be possible, at least its magnitude) because it wouldnt mean much given our everyday experience of the world. No wonder then that we get classical 'particle' answers.

[elas]

The answer to the question is.........'wave'

I have a collection of cuttings on electrons that include several images of electrons on their own and within an atom. These images are produced by various types of experiments.
If electrons consists only of a wave, and the wave exist only in model form; how are these images achieved?

[Albrecht]

Otherwise, non-composite particles (electrons, muons, taus, neutrinos and quarks) would not show a wave-like behavior, and they all do.
According to mainstream physics leptons and quarks are not composite. This was concluded from experiments:

In experiments it was tried to decompose such particles by bombarding them by high energy particles in an accelerator. They could not be decomposed even though the energy should have been sufficient.

The misunderstanding of the case comes from the assumption that the constituents of an elementary particle, which has mass, must also have mass. This, however, is an unnecessary and most probably wrong assumption. The constituents do have no mass, and in this case such particle can never be decomposed irrespective of the energy used.

From the Dirac function of the electron it follows that the "inside" of an electron orbits at the velocity of light c. The orbital frequency is the deBroglie frequency. This orbital motion causes the alternating field. This is not the electric field but the field descibed by the Schroedinger equation.

The electric charge on the other hand causes a magnetic field during this circulation. If this is computed by classical electrodynamics, the result is the true magnetic moment of the electron within a rel. accuracy of 0.001 .

By a similar calculation the constancy of the spin of any particle can be computed by classical means.

Isn't this a good prove that the electron is this way?

[christench]

I think I may have seen the same pictures of electrons, in crystals for example. These experiments are trying to image a wave. They set out to achieve it and use techniches that will get results. And they aparently work.

But dont we always measure what we are interested in for our model? Im certain you could find many pictures where the electron has acted like a particle, your monitor might be doing it now. You could devise an experiment to picture the electron as a particle. Sure enough you could get the result you want.

The way we design our experiments is determined by our model. If we model the electron as a wave we set out to observe the wave, or at least wave nature. If we model it as a particle, we ask particle questions in the experiment and get particle results.

In the end the model of an electron as a 'wave' is ALWAYS good, at least as far as our current experimental ability is concerned. Who knows, it may have to be modified in the future.

[Albrecht]

If we model the electron as a wave we set out to observe the wave, or at least wave nature. If we model it as a particle, we ask particle questions in the experiment and get particle results This is an intelligent consideration. However, the situation seems to be much simpler. If you assume, like deBroglie did, that the electron is a real particle, this particle has an internal oscillation which causes the wave around it, you will not find an experiment, which contradicts this assumption.

Using this approach, you can calculate the particle parameters (like e.g. the magnetic momentum) in a classical way, in contrast to what you find in books of quantum mechanic; those books state that, in the assumption that the electron is a wave, the parameters (magn. moment, spin etc) can only be understood by QM. It is different!

If you like more details please look into http://www.ag-physics.org/electron

[christench]

If you like more details please look into http://www.ag-physics.org/electron

This is an interesting site, attempting to explain quantum mechanics in terms of classical mechanics. Of course this is always the aim because we only intuitively understand classical physics. Usually its left to semi-classical physicists. In semi-classical you can use classical trajectories, assuming non-classical ones interfere destructively, and give them a phase and then Bobs your uncle: Quantisation using classical laws of motion. At this web site there is no attempt at quantisation. There is a hand waving argument at an explaination of spin quantisation, but it is not at all convincing.
Classical mechanics just cannot cover the spectrum of phenomena we can observe in quantum systems. There is a strong connection between the two extreems, one is just the limiting case of the other, and thats why you can compute parameters such as energy states of the hydrogen atom using largely classical equations (the Bohr atom) for example.

[Albrecht]

At this web site there is no attempt at quantisation. There is a hand waving argument at an explaination of spin quantisation, but it is not at all convincing.
The quantization for the electron state in an atom was explained by Louis de Broglie in his famous paper
www.davis-inc.com/physics/broglie/broglie.shtml

His explanation is compatible with the model presented on the web site referred above.

The constancy of the spin of all elementary particles (i.e. leptons and quarks) is proven classically using the assumption, that elementary particles oscillate internally with c. This was given by Paul Dirac in 1928 for the electron. It is assumed that this is true also for the other elem. particles.

It is true that the quantization of spin measurement, which is in fact the interaction of the electron's magnetic momentum with an external magnetic field, is not quantitatively explained. Only the mechanism which will most probably cause this, is explained. But, please keep in mind that quantum mechanics also does not explain this but only states the fact as existing by an appropriate formalism (as quantum mechanics never explain anything). So, maybe an incomplete explanation is better than no explanations at all (which is QM) because it shows the possible direction of the answer.

Classical mechanics just cannot cover the spectrum of phenomena we can observe in quantum systems.
christench: can you please give 1 or 2 more examples of this spectrum of phenomena?

[cmbezln]

Originally posted by benzun_1999
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.
[;)]

I've read some pretty compelling evidence that electrons only act as a particle when we view them with our eyes. When we are not, they act as wave existing throughout the universe at once. Even when electrons do posess qualities of a "particle", they only show "tendencies" to exist at best.

[Albrecht]

Even when electrons do posess qualities of a "particle", they only show "tendencies" to exist at best.
According to Louis de Broglie (Nobel price 1929) particles like the electron are real particles with a wave around. This wave around causes the interference phenomena and the quantization.

If you know any experiment, which is in conflict with this assumption, please let us know.

[selfAdjoint]

Read John Gribben's book "Schroedinger's Kittens" it's full of experiments showing the non-intuitive nature of the electron and photon.

And Bell's inequalities and the experiments, starting with Aspect's, that confirmed them knock simple hidden variable theories on the head. That would include deBroglie's. Bohm's modification of de Broglie's theory does not violate Bell's inequalities, but is not Lorentz covariant, while just tons of experiments and the everyday experience of cyclotron pattern accelerators and cosmic rays show that Lorentz covariance is real.

There is a recent modification to Bohm's theory that is claimed to be covariant, but I know nothing about it.

[jcsd]

You cannot derive QM from classical physics (just like you can't derive relativistic QM from QM or SR) it is 'new' physics. De Broglie's explanation as was is insufficent, though Bohm's extenstion of this explanation can describe QM it has several problems mentioned several times in this thread.

Generally you encounter huge problems when you try to create a realist explanation of QM.

[Albrecht]

And Bell's inequalities and the experiments, starting with Aspect's, that confirmed them knock simple hidden variable theories on the head.
It was widely discussed in the course of this series of threats that the assumption of de Broglie regarding the pilot wave has absolutely nothing to do with
1. Bell's inequality
2. the experiments of Aspect

Bell himself was always in favour of the pilot wave assumption. He worked for a long time at the Cern accelerator and, to my knowledge, never found an argument against the assumption that
1. the electron is a real particle
2. the pilot wave is responsible for the interference phenomena.

And by the way: where did I mention hidden variables?

But thanks for the reference to John Gribben. Shall try to get it.

Generally you encounter huge problems when you try to create a realist explanation of QM.
I know, of course, this argument. But it is too general and so it cannot clarify anything.

[jcsd]

Well huge problem no.1 is non-locality, which is very dificult to explain within a relist concept without introducing concepts such as the quantum potential leaving the theory ontologically unsatifying.

[Albrecht]

Well huge problem no.1 is non-locality
The pilot wave has nothing to do with non-locality.

If you throw a stone into the water it generates waves. Do we in this case have a problem with non-locality or with hidden parameters?

I guess we do not.

It is a similar process if an oscillating electron moves through the space an causes a surrounding wave.

[jcsd]

Au contaire the biggest tumbling block for Bohm's interpretation is that a non-local quantum potential may affect the particle and visa versa. There are reasons why the De Broglie-Bohm interpretation is not the convential interpretation.

[pelastration]

Albrecht speaks about de Broglie, you jcsd comes always back on Bohm.

[jcsd]

Originally posted by pelastration
Albrecht speaks about de Broglie, you jcsd comes always back on Bohm.

The reason for this is that Bohm is responsible for developing the pilot wave theory, so you can talk about De Broglie if you want but if your talking about a consistent pilot wave model of QM you have to talk about Bohm.

[Albrecht]

if your talking about a consistent pilot wave model of QM you have to talk about Bohm
I do not know where this (very common) misunderstanding comes from. Bohm had a very special interpretation about where the pilot wave comes from. He tried to generate a deterministic Schroedinger-like wave function, which is a different case.

The model I have explained is in contrast very easy. In this model an electron emitting a wave is quite similar to a radio antenna transmitting a wave. Do radio antennas have a problem with locality?

John Bell who worked on this topic for about 30 year (e.g. as a theoretical physicist at the Cern accelerator) stated that he never found a real argument against the pilot wave.

[jcsd]

Albrecht, Bohm's interpretation is the pilot wave interpretation, De Broglie's is just undeveloped version of this, certainly no-one with knowledge of QM would put forward De Broglie's explanation by itself.

I think the misconception is on your part.

Of course non-locality must involved as hv theory must be non-local.

[jcsd]

I'll also add De Broglie himself abandoned the pilot wave interpreation in 1935 due to it's non-locality.

[jammieg]

The question remains unanswered to my expert laymen's knowledge, why should one electron be affected by another that are not occupying the same apparatus at the same time? One particle's wake is influencing another particle's trajectory, so what is it that is retaining the information of the wake? If there were nothing to retain the information of the previous electron then a series of the apparatus all firing one electron should also when compiled produce a wave pattern, but if they don't then there is information being retained by something in each emission.

[Albrecht]

Bohm's interpretation is the pilot wave interpretation, De Broglie's is just undeveloped version of this
This is not correct. De Broglie has worked out his pilot wave theory later in his life. - Was it good or bad? - Nobody knows because his work on this topic was completely ignored by the physical community.

John Bell demonstrated in his book "Speakable and Unspeakable in QM ..." a simple version of a pilot wave approach which was in no conflict with physical fundamentals. Do you know it? Also this approach has no problem with non-locality. And everyone can be sure that Bell new this argument.

(Bohm was special because he has built a mix out of main stream QM and of something new. Such mix easily causes conflicts.)

I have tried to show that the particle wave phenomenon can quite easily be understood starting at de Brogie's fundamental idea and further using only classical physics. Every time when I explain this at this place, the response is: "The theory of Bohm has the following conflicts: ......"

It feels indeed as if everyone has undergone a kind of brainwash.

I'll also add De Broglie himself abandoned the pilot wave interpreation in 1935 due to it's non-locality.
This is also not true. When at the Solveig conference in Brussels in 1927 Bohr and Heisenberg were successful to fight de Broglie (and Einstein) down by not only physical arguments, de Broglie gave up for a time. He received a position at a reputated physical institute to educate students. He decided to give lessons about the current main stream QM. His argument was that he did not want to cause conflict to the students. But he has written down at that time that the lessons contradicted his conviction.

After he ended this job he continued his original way. (But was pushed out of the physical community. Maybe he could be happy not to be burned!)

[selfAdjoint]

Okay, this is fair. Let's forget Bohm and all the Bohm history for a time and just consider your de Broglie pilot wave theory. Yes I do have Bell's "Speakable and Unspeakable" but lord knows where it is since my move. I'll try to find it and respond to your discussions.

[jcsd]

The problem, is though self-adjoint you won't find any modern texts on solely De Broglie's interpretation as the approach as it is now was deveolped by Bohm.

Albrecht, your talking ****, I know what the pilot wave is as I've been taught in a formal setting (i.e. university).

The problem is you can't explain QM in the manner you describe, you cannot derive Schroedinger's wave equation in it's entirity or Dirac's equation using classical physics and wave-particle duality, deriving these equations are an inductive process.

[jcsd]

Read this passage:

Bohm gave the uncertainty principle a purely physical rather than metaphysical meaning. Bohr had interpreted the uncertainty pn'nciple, Bohm explained, as meaning "not that there is uncertainty, but that there is an inherent ambiguity" in a quantum sv'tem. Bohm sent out preprints of the paper and was quickly informed that his interpretation was an old one, proposed 25 years earlier by Louis de Broglie. De Broglie had abandoned the pilot-wave concept after Wolfgang Pauli pointed out that, when applied to systems involving more than one particle, it led to "some very strange behaviour" This strange behaviour referred to by Pauli, Bohm realised, was nonlocality. Actually, nonlocality was a feature intrinsic to all quantum theories, not just Bohm's. Einstein had demonstrated this fact back in 1935 in an effort to show that quantum mechanics must be flawed.

http://www.uncletaz.com/library/scimath/pilotwave.html

[Albrecht]

you cannot derive Schroedinger's wave equation in it's entirity or Dirac's equation using classical physics and wave-particle duality
The task is not to derive Schroedinger's wave equation or Dirac's equation but to explain what happens in physics.

I am indeed interested in any kind of criticism, but please refer to the statements I have made in detail and tell what you find wrong.

It does not clarify anything if only and permanently reference is made to others who may have produced improper theories.

Yes I do have Bell's "Speakable and Unspeakable" but lord knows where it is since my move. I'll try to find it and respond to your discussions.
Great. In the chapter "The impossible pilot wave" Bell states that he was looking for arguments of Bohr, Heisenberg etc. usable against the pilot wave approach. He never found any. The persons rejecting the theory of de Broglie just ignored him, nothing better.

[jcsd]

Originally posted by Albrecht
The task is not to derive Schroedinger's wave equation or Dirac's equation but to explain what happens in physics.

I am indeed interested in any kind of criticism, but please refer to the statements I have made in detail and tell what you find wrong.

It does not clarify anything if only and permanently reference is made to others who may have produced improper theories.


Great. In the chapter "The impossible pilot wave" Bell states that he was looking for arguments of Bohr, Heisenberg etc. usable against the pilot wave approach. He never found any. The persons rejecting the theory of de Broglie just ignored him, nothing better.

But you need Schroedinger's wave equation to explain quantum mechanical results, something classical physics cannot explain.

The pilot wave uses a slightly altered form of Schroedinger's wave equation.

[selfAdjoint]

Well, I found Bell's book and scanned the entries. I carefully read #17, "The Impossible Pilot Wave" and #14, "de Broglie=-Bohm, delayed choice double-slit experiment, and density matrix". I think I understand what he says in each one.

In #17, in addition to discussing the failures of the no-go theorems, he defines his model in simple terms. In #14 he applies the model to a classic experiment, first giving the pilot wave explanation of the apparent self interference, and then attempting an explanation of the delayed choice variant.

I am not interested in rehashing whatever problems deBrogie, Bohm, Bell, or for that matter Einstein had with whatever passed for the scientific establishment of their day. I am interested in the positive statements of the pilot wave model and how it accounts for reality.

You oftern hear it said that Bohm theory (sorry to focus on that) has the same predictions as QM. The discussions in #14 show that this is not a trivial statement. A separate argument and considerable ingenuity had to be applied to get the actual results of this basic experiment out of the pilot wave and particle model. In fact I find the account of the delayed choice part of it rather implausible.

[metacristi]

I don't think the delayed choice in the two slit experiment really challenge Bohm's interpretation since the quantum potential (a quantum field) is postulated to change instantly in the whole of space.The interference pattern disappear when one slit is closed (quantum potential change instantaneously) still the electron,postulated to have a definite position and velocity,is guided by the part of the pilot wave that goes through the open slit.The only objection here is (as I've pointed out in one of my previous posts on this thread) that the trajectory of the electron when one slit is closed is different from that when both slits are open.Or the change of trajectory when one slit is closed after the particle has already gone through one of the slits (more generally after it departs from the source) implies that the electron (a particle) should radiate away energy which we do not detect practically.Not an insurmontable problem,Vigier's proposal that this energy has a very large wavelength is much more than an ad hoc explanation.

[Albrecht]

But you need Schroedinger's wave equation to explain quantum mechanical results, something classical physics cannot explain.
Which results do you mean? - The Schroedinger equation was only the first step towards QM. Schroedinger himself never agreed to the QM as developed by Bohr and Heisenberg.


A separate argument and considerable ingenuity had to be applied to get the actual results of this basic experiment out of the pilot wave and particle model.In fact I find the account of the delayed choice part of it rather implausible.

Where do you see a problem? The particle is at every instant fully guided by the surrounding wave and so it's statistical distribution - also if this is registered by the plate which is inserted by the delayed choice - reflects the interference distribution of the wave.

If there are differences between the QM solution and the pilot wave solution they will, at least according to Bell, not be discernible in an experiment.

[jcsd]

The energy levels of electrons, the probailty of finding a particle in a certain point for a start the Schroedinger wave equation is key to QM.

[Albrecht]

The energy levels of electrons
These are fully explained by the requirement of de Broglie for the phase fit of the pilot wave of the electron in it's orbit. It does not require a Schroedinger equation where the amplitude is a probability amplitude.

the probailty of finding a particle in a certain point for a start the Schroedinger wave equation is key to QM
This probability is only an interpretation of the Schroedinger equation. There is no direct experimental proof that this interpretation is correct.

[jcsd]

The probalistic interpretaion is important in QM, I just find your die-hard support of De Broiglie's interpretation strange since it's not beeen taken seriously by itself for years.

[Albrecht]

The probabilistic interpretation of QM was in fact a matter of "zeitgeist" (spirit of the age) for more than 70 years. I know of several persons (physicists of international reputation among them) who have a different opinion but do not dare to say this in public.

Nobody wants to share the fate of de Broglie.

But on the other hand I have the impression that time is going to change in respect to this.

We have in history examples of such situations. The proof of John von Neumann about the inconsistency between QM and a deterministic world was heavily discussed for 30 years, but nobody noticed the logical error in the beginning of it. Until John Bell came.

And ealier and worse: the law of free fall of Aristotle was believed for 2000 years, before Galilei showed in a very easy way that this law was logically impossible.

There is more of this. And we still live in the same world.

[Tom D]

"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"


I can't remember which book, but one of the most helpful pieces of advice I read concerning atoms, 'elementary' particles and more than 3 spacial dimentions is to realise that these things do not in any way relate to anything else we could possibly directly experience or imagine-- and the best way to have some understanding is to make do with a metaphor but never forget that any description or model we use is just that and not the actuality itself.
If it helps someone model an electron as a wave to achieve a result but it also helps achieve another result by using a particle model, then either/both will do.However, the actuality is that an electron is something that we don't know what it is.
This (forgotten name, sorry ) goes on to say that if you are in doubt as to whether a metaphor or true description can be applied, then try changing the name of what you want to a fantasy name and describe it then see if it changes your perception of it. If your perception is changed, then the original could be described as it actualy is. If you have lost no meaning by using fantasy name, then a metaphor is the best you can do.
e.g. if you think of a brick, change its name to say, "hoopydoopy".
Describe it.It's mass is 200g. It's dimensions are 100mm,70mm and 60mm. It's a solid cuboid. There is one precisely 1 m in front of me et. etc. Hoopydoopy sounds wrong, brick sounds right.
If you think of an electron, change its name to say, hoopydoopy".
Describe it.It's mass is ...eV. It's dimensions are..er...unspecific. It has no defined shape. There is a probability amplitude of one being somewhere between a and b etc etc. Hoopydoopy sounds no more odd than electron so we can not decribe it other than a model or abstract values of measurements.
An all-knowing being could no more describe these things to us as we could describe a fish to a garden snail--it just doesn't have the language, experience or perceptive abilities ( all related ? )to catch on.
I know this seems a bit stupid and barmy, but try it out and you'll see what I mean.

[selfAdjoint]

Marvelous, Tom. And even down in the gears of QED, with the density matrices and Feynmann propagators, that's still metaphor. A metaphor with the property of supporting arithmetic calculations. But it doesn't "explain" anything.

[Albrecht]

But it doesn't "explain" anything.
Why are we willing to exept, not to understand physics?

A close friend and co-worker of Werner Heisenberg (the German physicist Von Weizsäcker) has once said in a speech: If a physicist these days still tries to understand physics, he does not have the maturity to work on the physical field.

Do we really have the chance for a further development of physics if we accept such a statement/believe?

[Tom D]

I think it's an unreasonable pessimism in the abilities of people.
If we learn that we can not ( yet, but who knows what abilities human brains may evolve ) hope to 'picture' ,say, an electron in it's 'true form' then we have understood that an electron is not visible , which is still learning. The mathematical models ( metaphors ) still allow us to understand the electron better than before applying the descriptions ( measurements ).
Only a religious-inspired all-knowing being would know all physics , which is infinite in scope ( or, the models are, even if the universe is not ) but we can always learn more aand understand more without limit even if we never reach the final 'truth', which may not be a constant truth.
Perhaps our communication and minds will develop to take our understanding to realms beyond our current imagination, but I believe those descendant of ours will still find their understanding is yet not full.

[Tom D]

A simple way to think of ( non-rotational ) non-movement and movement in spacetime at small and large velocities without considering mass is this:
Essentially, all things relatively translate (move) through spacetime at 'velocity' C = speed of light in vacuam.This velocity is shared between space and time such that the sum of the translation distance in space + translation distance in time = C.
So the slower something moves, the more time it experiences.
Staionary objects experience 'maximum' time.
Faster objects experience less time.
Light ( velocity C ) experiences no time which is why they have'infinite' lifetime.
As for clocks, a stationary ( to us ) observer sees a fast spaceship's clock as slow and his/her clock is normal, but the captain sees that the observer's clock is also slow, as both have the same relative speed, while captian also sees his clock is normal.
Two spaceships in formation see each other's clocks as normal.

{edit:} the above applies to constant motion.
Anyone please explain what happens to spacetime during acceleration (+ve and -ve) both for -ve and +ve velocities of the spaceship e.g. the spaceship +vely accelerates away from earth, -vely accelerates to standstill,does not turn around but uses reverse thrust and -vely accelerates toward Earth, then +vely accelerates to a standstill back on the launchpad.

[Albrecht]

Essentially, all things relatively translate (move) through spacetime at 'velocity' C = speed of light in vacuam.This velocity is shared between space and time such that the sum of the translation distance in space + translation distance in time = C.
Congratulations! You are the first one who has found this up to now (besides myself).

Do you realize the consequences?

If you understand time as the internal motion within an object, the conclusion is, that the innermost parts of our matter move permanently with the speed of light c.

This in turn explains special relativity. I.e. a physical understanding of relativity, in contrast to Einstein, who has created a so called "geometrized" theory of relativity.

I have worked this out and put it into the web:
http://www.ag-physics.org/relat

... and, by the way, you will also find a link to a site about the electron which shows to which extend an electron can be understood classically. In contrast to all what you find in textbooks about QM.
http://www.ag-physics.org/electron

[Karl G.]

According to the de Broglie equation, all particles have 'wavelike' properties. So to say that an electron is a particle or a wave is really inaccurate - it is both. Furthermore, the Schrodinger equation states that the exact position of an electron is probabalistic until measurement, and represents a 'superposition of states'. This makes the concept concept of an electron represented by a wave, particle, or anything even more chimerical. In my view, we shouldn't worry 'what' an electron is. Representing it as an abstract, quantum state, while not descriptive of what an electron 'looks' like, accurately describes all of its properties.

[jtbell]

Congratulations, I think you have just set a PF record by reviving a thread after over five years and four months. :biggrin: