Are electrons wave or a particle?

[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 realized, 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 spatial dimentions is to realize 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 Feynman 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.