What makes an electron orbit?

questionposter · May 5, 2012

From your post #19

Which still isn't wrong according to multiple variations of quantum mechanics

juanrga · May 5, 2012

Maybe it is worth to mention that chemists also know that the electron is a particle. Indeed the International Union of Pure and Applied Chemists gives the following official definition of the electron:

Elementary particle not affected by the strong force having a spin quantum number $E01975-0.png$ , a negative elementary charge and a rest mass of $E01975-1.png$ .

It must be interesting to add that the Particle Data Group has an entry devoted to the electron. That entry gives the last measured data about the electron

http://pdg.lbl.gov/2...s_listings.html

The citation is 2011 Review of Particle Physics.

Please use this CITATION: K. Nakamura et al. (Particle Data Group), J. Phys. G 37, 075021 (2010)

and 2011 partial update for the 2012 edition.

This is an article by Weinberg stating that the electron is a particle and critizing the old idea of particles as excitation of fields.

Some more resources stating that the electron is a particle

http://www.web-books...MParticles.html

An elementary particle is the particle which does not contain smaller particles. For instance, the electron is an elementary particle.

And more giving only the links:

http://en.wikipedia....st_of_particles

http://www.particlep...dard-model.html

http://www.particlep...-particles.html

http://ctp.berkeley..../neutrino3.html

http://www.arpansa.g...glossary.cfm#e7

http://www.nap.edu/o...d=6045&page=161

http://education.yah...ntry/elementr-p

And finally I would like to add a Nobel Lecture by Dirac. This is particularly delicious, because Dirac uses the old relativistic wave mechanics that he developed (recall that he wrote this in 1933!), but emphasizes to a broad public that electrons are... particles:

Matter has been found by experimental physicists to be made up of small particles of various kinds, the particles of each kind being all exactly alike.

[...]

The simpler kinds of particle are:

(i) the photons or light-quanta, of which light is composed;

(ii) the electrons, and the recently discovered positrons (which appear to be a sort of mirror image of the electrons, differing from them only in the sign of their electric charge) ;

(iii) the heavier particles - protons and neutrons.

Edited May 5, 2012 by juanrga

questionposter · May 5, 2012

In previous posts you alluded to some chemist. Maybe it is worth to mention that chemists also know that the electron is a particle. Indeed the International Union of Pure and Applied Chemists gives the following official definition of the electron:

It must be interesting to add that the Particle Data Group has an entry devoted to the electron. That entry gives the last measured data about the electron

http://pdg.lbl.gov/2...s_listings.html

The citation is 2011 Review of Particle Physics.

Please use this CITATION: K. Nakamura et al. (Particle Data Group), J. Phys. G 37, 075021 (2010)

and 2011 partial update for the 2012 edition.

This is an article by Weinberg stating that the electron is a particle and critizing the old idea of particles as excitation of fields.

Some more resources stating that the electron is a particle

http://www.web-books...MParticles.html

And more giving only the links:

http://en.wikipedia....st_of_particles

http://www.particlep...dard-model.html

http://www.particlep...-particles.html

http://ctp.berkeley..../neutrino3.html

http://www.arpansa.g...glossary.cfm#e7

http://www.nap.edu/o...d=6045&page=161

http://education.yah...ntry/elementr-p

Most if not all of your definitions for "particle" that you found on the internet do not exclude an electron from being a wave or being able to oscillate. Magnetic orientation and angular momentum and energy and etc. are used in quantum wave mechanics and quantum harmonic oscillators.

juanrga · May 5, 2012

Most if not all of your definitions for "particle" that you found on the internet do not exclude an electron from being a wave or being able to oscillate. Magnetic orientation and angular momentum and energy and etc. are used in quantum wave mechanics and quantum harmonic oscillators.

All the references state that an electron is a particle not a wave. A particle can oscillate and it continues being a particle, not a wave. A particle has angular momentum and energy and continues being a particle not a wave. Dirac also agree on that the electron is a particle.

questionposter · May 5, 2012

All the references state that an electron is a particle not a wave. A particle can oscillate and it continues being a particle, not a wave. A particle has angular momentum and energy and continues being a particle not a wave. Dirac also agree on that the electron is a particle.

I don't really think you have the capability to disprove that a particle can be a wave, but at least your making progress by admitting what most of quantum mechanics works with which is that they do have oscillation patterns. Besides I don't mind if they aren't actually a wave, I had originally adjusted my description to say that an electron is an oscillation in a matter field, which isn't that difficult of a concept.

Edited May 5, 2012 by questionposter

juanrga · May 6, 2012

quantum mechanics works with which is that they do have oscillation patterns.

There are not "oscillation patterns" because the electron is not oscillating.

The ordinary quantum mechanics of particles explains the well-known interference patterns observed when thousands of particles impact a screen in a double-slit experiment. Next is the sequence of patterns obtained when the experiment is repeated; each white point is where one electron impacted the photographic screen. (e) is the observed interference pattern when a large number of electrons has already impacted the photographic screen.

Besides I don't mind if they aren't actually a wave, I had originally adjusted my description to say that an electron is an oscillation in a matter field, which isn't that difficult of a concept.

The electron is never "an oscillation in a matter field".

There is an old interpretation in quantum field theory, where an electron is an excitation of a fermionic field. But modern formulations do not support this view and fermionic fields are derived as unobservable systems, when doing certain approximations in the interaction Hamiltonian of a system of particles (electrons).

Edited May 6, 2012 by juanrga

derek w · May 6, 2012

juanrga are you saying that an electron is neither an oscillation nor a wave function?

If so how do you explain the interference pattern in fig:- e

questionposter · May 6, 2012

There are not "oscillation patterns" because the electron is not oscillating.

The ordinary quantum mechanics of particles explains the well-known interference patterns observed when thousands of particles impact a screen in a double-slit experiment. Next is the sequence of patterns obtained when the experiment is repeated; each white point is where one electron impacted the photographic screen. (e) is the observed interference pattern when a large number of electrons has already impacted the photographic screen.

The electron is never "an oscillation in a matter field".

There is an old interpretation in quantum field theory, where an electron is an excitation of a fermionic field. But modern formulations do not support this view and fermionic fields are derived as unobservable systems, when doing certain approximations in the interaction Hamiltonian of a system of particles (electrons).

Yes, an electron can be excited and form interference patterns, and both of those things happen in quantum wave mechanics.

hypervalent_iodine · May 6, 2012

First a remark: I am not giving my own definition of particle. I am alluding to the standard definition of particle used in a branch of science named particle physics.

It is this standard definition which Weinberg alludes to, when he emphasizes that "the electron is a particle" and when writes "The quantum theory of particles like electrons". When Weinberg writes in his talk that he starts with "Wigner's definition", he means Wigner definition of particle. It is this standard definition of particle which leads to Weinberg to say in his talk that the "old dualism" is "safely dead and will never return". This is the standard definition of particle used by guys at CERN when write, in their own website, that electrons are particles and that:

Evidently, CERN guys do not mention old myths as "dualism", "matter waves", and all that outdated and nonsensical stuff.

I have given a table of elementary particles in #114. Composite particles are made of elementary particles. For instance a proton is made of 2 quark-up plus 1 quark-down.

About the link, I just click in the link in the above post and it works for me, opening a new tab in my FF browser with the next webpage from Google Books:

!

Moderator Note

juanrga,

Your style of posting in the above lends itself towards being rather condescending. This isn't a great way to hold a discussion and begs a defensive rather than a cooperative response, which is not what we would like membership to aim for when posting. This forum isn't about winning or losing a debate, it's about holding civil and informative discussion. It is of course, okay to disagree with someone, but you need to be more mindful of your tactics in future.

Please do not derail this thread by responding to this mod note.

juanrga · May 7, 2012

juanrga are you saying that an electron is neither an oscillation nor a wave function?

If so how do you explain the interference pattern in fig:- e

An electron is a particle. A particle is a physical system, neither a kind of motion nor a kind of function. As stated before, the ordinary quantum mechanics of particles explains the interference patterns observed when thousands of particles impact a screen in a double-slit experiment.

There are not "oscillation patterns" because the electron is not oscillating.

The ordinary quantum mechanics of particles explains the well-known interference patterns observed when thousands of particles impact a screen in a double-slit experiment. Next is the sequence of patterns obtained when the experiment is repeated; each white point is where one electron impacted the photographic screen. (e) is the observed interference pattern when a large number of electrons has already impacted the photographic screen.

The electron is never "an oscillation in a matter field".

There is an old interpretation in quantum field theory, where an electron is an excitation of a fermionic field. But modern formulations do not support this view and fermionic fields are derived as unobservable systems, when doing certain approximations in the interaction Hamiltonian of a system of particles (electrons).

Yes, an electron can be excited and form interference patterns, and both of those things happen in quantum wave mechanics.

Yes, an electron can be excited, but above I wrote about the excitation of a field.

An electron alone does not form an interference pattern. Eleven electrons do not form an interference pattern (a). Thousands of electrons form an interference pattern (e).

Yes, the quantum 'wave' mechanics of particles can explain some aspects of excited electrons and can explain some aspects of interference patterns. As stated before, more general quantum mechanical formulations can explain other aspects beyond the quantum 'wave' mechanics formulation.

Edited May 7, 2012 by juanrga

studiot · May 7, 2012

Questionposter,

You may wish to know that other (recent) Nobel Laureates in Physics have views closer to your own.

Here is a quote from "The Lightness of Being" by Frank Wilczek

........If a theory has a lot of parameters and you adjust their values to fit a lot of data your theory is not really predicting those things, just accomodating them. Scientists use words like curve fitting and fudge factors to describe that sort of activity. Those phrases are not meant to be flattering. On the other hand, if a theory has just a few parameters, but applies to a lot of data it has real power......

In this book, Wilczek discusses the role of modern QM in the scheme of things, what it achieves and does not achieve. Nowhere does he state explicitly or imply that duality has been superceeded. Rather he interprets WM as providing probabilities of observing a particular particle or particle property.

questionposter · May 7, 2012

An electron is a particle. A particle is a physical system, neither a kind of motion nor a kind of function. As stated before, the ordinary quantum mechanics of particles explains the interference patterns observed when thousands of particles impact a screen in a double-slit experiment.

Yes, an electron can be excited, but above I wrote about the excitation of a field.

An electron alone does not form an interference pattern. Eleven electrons do not form an interference pattern (a). Thousands of electrons form an interference pattern (e).

Yes, the quantum 'wave' mechanics of particles can explain some aspects of excited electrons and can explain some aspects of interference patterns. As stated before, more general quantum mechanical formulations can explain other aspects beyond the quantum 'wave' mechanics formulation.

No, according to modern QM a single electron DOES make an interference pattern, but you don't directly see it with your eyes because it's just one electron. It's only after time of many many electrons interfering with themselves can you see the pattern. The same exact pattern can be formed by waves.

Edited May 7, 2012 by questionposter

juanrga · May 7, 2012

Questionposter,

You may wish to know that other (recent) Nobel Laureates in Physics have views closer to your own.

Here is a quote from "The Lightness of Being" by Frank Wilczek

In this book, Wilczek discusses the role of modern QM in the scheme of things, what it achieves and does not achieve. Nowhere does he state explicitly or imply that duality has been superceeded. Rather he interprets WM as providing probabilities of observing a particular particle or particle property.

That is a non-technical book for broad audiences where he makes many jokes invent names as the "Hub" appeal to The Matrix of pop culture... As explained before the wave-particle duality myth is very popular in historical and popular treatises.

Wilczek has a paper (Quantum field theory), published in Reviews of Modern Physics, where he revises the fundamental principles of what he considers "a complete foundation for atomic physics and chemistry". He never mention duality, consider electrons and photons as particles, and explains how the original wave-functions of Dirac are abandoned in favour of field operators. I am glad that we agree on those.

No, according to modern QM a single electron DOES make an interference pattern, but you don't directly see it with your eyes because it's just one electron. It's only after time of many many electrons interfering with themselves can you see the pattern. The same exact pattern can be formed by waves.

The ordinary QM of particles explains how a single electron interfere with itself (the technical explanation is other) and how the interference pattern in (e) is obtained when the experiment is repeated with thousand of electrons. There is not interference pattern in (a) as is self-evidently.

No, the same pattern is not formed by "waves", this is the reason which quantum mechanics was developed to explain this and other experiments.

Edited May 7, 2012 by juanrga

studiot · May 7, 2012

I think the point I was trying to make (along with others) is that the 'particle' is not a particle in the conventional (classical) sense, all concentrated at a specific location.

QM, old or new, allows finite probabilities of it being at a (many) different point(s).

questionposter · May 7, 2012

I think jaungra needs to actually explain what he thinks a particle actually is according to his sources. Otherwise I don't see why he's making a big deal that a particle can't possibly be a wave.

Also, the same pattern IS formed by waves

Even pop-science knows that. Quantum wave mechanics wasn't pulled out of thin air.

Not only that, but the term "duality" isn't mentioned because that's not the proper name, the proper name is "quantum harmonic oscillator".

http://en.wikipedia....onic_oscillator

Edited May 8, 2012 by questionposter

juanrga · May 8, 2012

I think the point I was trying to make (along with others) is that the 'particle' is not a particle in the conventional (classical) sense, all concentrated at a specific location.

QM, old or new, allows finite probabilities of it being at a (many) different point(s).

I have emphasized several times in this thread that a quantum particle is not a classical particle. It is evident that the quantum mechanics of particles was developed about 1930 because the classical mechanics of particles could not explain all the properties and the behaviour of particles as the electrons.

I have given the particle physics definition of particle (both link and snapshot from textbook) and, of course, nowhere the definition alludes to classical particles.

I think jaungra needs to actually explain what he thinks a particle actually is according to his sources. Otherwise I don't see why he's making a big deal that a particle can't possibly be a wave.

'jaungra' already explained what is a particle, gave a precise definition of particle, gave dozens of references supporting his points, gave the physical properties that characterize a particle, gave a table of particles with their properties, and also explained to you that a particle is not a "little sphere". 'jaungra' does not need to do all that again.

Also, the same pattern IS formed by waves

Even pop-science knows that.

I could not agree more with the first comment about that video:

misunderstandings about this experiment are the source of a lot of pop-culture BS about quantum physics.

Not only that, but the term "duality" isn't mentioned because that's not the proper name, the proper name is "quantum harmonic oscillator".

http://en.wikipedia....onic_oscillator

This is all wrong. Duality has nothing to see with a quantum harmonic oscillator. A quantum harmonic oscillator is a kind of quantum system.

A quantum oscillator is the quantum analogue of a classical oscillator.

The same link that you give explains how to study the quantum oscillator starting from the "Hamiltonian of the particle", "where m is the particle's mass", and the the "first term in the Hamiltonian represents the kinetic energy of the particle", and solving H|Psi> = E|Psi> for the particle (I already wrote this equation before in this thread).

Again, no mystery here. The quantum mechanics of particles continue working as well as it always did. Misunderstandings about quantum mechanics in the pop-culture (read again the comment in the youtube video) do not change the facts about quantum mechanics or about particle physics.

Edited May 8, 2012 by juanrga

questionposter · May 8, 2012

I have emphasized several times in this thread that a quantum particle is not a classical particle. It is evident that the quantum mechanics of particles was developed about 1930 because the classical mechanics of particles could not explain all the properties and the behaviour of particles as the electrons.

So let me get this straight: You think a wave is a classical particle?

'jaungra' already explained what is a particle, gave a precise definition of particle, gave dozens of references supporting his points, gave the physical properties that characterize a particle, gave a table of particles with their properties, and also explained to you that a particle is not a "little sphere". 'jaungra' does not need to do all that again.

I have given the particle physics definition of particle (both link and snapshot from textbook) and, of course, nowhere the definition alludes to classical particles.

No one is saying quantum particles are classical particles.

I could not agree more with the first comment about that video

Just because your incapable of comprehending it doesn't mean it's wrong.

This is all wrong. Duality has nothing to see with a quantum harmonic oscillator. A quantum harmonic oscillator is a kind of quantum system.

Yes it is a system, one that deals with much of the same mathematics that waves use.

The same link that you give explains how to study the quantum oscillator starting from the "Hamiltonian of the particle", "where m is the particle's mass", and the the "first term in the Hamiltonian represents the kinetic energy of the particle", and solving H|Psi> = E|Psi> for the particle (I already wrote this equation before in this thread).

What's your point?

Again, no mystery here. The quantum mechanics of particles continue working as well as it always did. Misunderstandings about quantum mechanics in the pop-culture (read again the comment in the youtube video) do not change the facts about quantum mechanics or about particle physics.

Your the only one that has even used the word "mystery" on this entire topic. I don't think there's anything strange about a quantum particle being acting like a wave, you do.

Edited May 9, 2012 by questionposter

studiot · May 8, 2012

A quantum oscillator is the quantum analogue of a classical oscillator.

Have a care with this statement.

What do you think the similarity of the classical oscillator equation is to the quantum wave equation?

Furthermore are you aware that an oscillator and a wave are different things?

Edited May 8, 2012 by studiot

juanrga · May 9, 2012

A quantum oscillator is the quantum analogue of a classical oscillator.

Have a care with this statement.

What do you think the similarity of the classical oscillator equation is to the quantum wave equation?

Furthermore are you aware that an oscillator and a wave are different things?

What has to see what I said with your questions?

So let me get this straight: You think a wave is a classical particle?

Evidently no.

What's your point?

That your previous statement about duality and harmonic oscillators was (sorry) nonsense:

Not only that, but the term "duality" isn't mentioned because that's not the proper name, the proper name is "quantum harmonic oscillator".

Your the only one that has even used the word "mystery" on this entire topic.

For emphasizing that there is not mystery...

Again, no mystery here. The quantum mechanics of particles continue working as well as it always did. Misunderstandings about quantum mechanics in the pop-culture (read again the comment in the youtube video) do not change the facts about quantum mechanics or about particle physics.

I don't think there's anything strange about a quantum particle being acting like a wave, you do.

It is a pure question of logic, physics, and math. A quantum particle is... a particle and not a wave. A cat is a cat and not an apple.

Edited May 9, 2012 by juanrga

studiot · May 9, 2012

What has to see what I said with your questions?

I think the comments were clear enough.

The (classical) oscillator equations (forced or not, linear or not) equations are quite different from the wave equation.

Quantum equations are different again.

One major difference is that classical equations employ real observables directly; the variables in quantum equations have to be interpreted in terms of real observables and this is where the different interpretations come from.

It is interesting to note that solutions to some classical equations can be interpreted in probability terms. Further the classical wave equation also has an uncertainty principle.

juanrga · May 9, 2012

A quantum oscillator is the quantum analogue of a classical oscillator.

Have a care with this statement.

What do you think the similarity of the classical oscillator equation is to the quantum wave equation?

Furthermore are you aware that an oscillator and a wave are different things?

What has to see what I said with your questions?

I think the comments were clear enough.

You made 3 questions unrelated to what I wrote.

The (classical) oscillator equations (forced or not, linear or not) equations are quite different from the wave equation.

Quantum equations are different again.

One major difference is that classical equations employ real observables directly; the variables in quantum equations have to be interpreted in terms of real observables and this is where the different interpretations come from.

It is interesting to note that solutions to some classical equations can be interpreted in probability terms. Further the classical wave equation also has an uncertainty principle.

Again, what has this to see with what I said about the oscillators?

Edited May 9, 2012 by juanrga

studiot · May 9, 2012

Again, what has this to see with what I said about the oscillators?

You are not the only person allowed to input to this thread (although you have certainly input a great deal and merit thanks for that).

Furthermore the original question was why does an electron orbit?

None has offered the original poster the obvious simple answer for the same reason the Earth orbits the Sun rather than falling directly into it, althought there is an an attractive force acting here too (gravity).

Was not the OP seeking an answer at this level?

Instead this thread has digressed to an argument about

"Is the electron a wave or a particle"

This argument has been excessively prolonged because neither side can agree on a definition of either a wave or a particle. This would seem to me a necessary precursor to resolving the argument.

The argument has been further clouded by the common practice of mixing up oscillatatory and wave motion. They are not the same.

Personally I am comfortable with the appropriate use of either model - yes they are both (incomplete) models of reality - both serve to more conveniently explain/model/predict one aspect or another of electron behaviour.

I left particle physics back in the radiochemistry lab at university in the late 60's. My life went in other directions after that and I spent the subsequent 50 years gaining experience applying my mathematics analysing all sorts of practical things. So I can easily spot a muddle when I see one.

Recently I have regained an interest in the more fundamental so I thank you for introducing me to modern thinking in this area, where you clearly have greater knowledge.

Edited May 9, 2012 by studiot

questionposter · May 9, 2012

What has to see what I said with your questions?

Evidently no.

That your previous statement about duality and harmonic oscillators was (sorry) nonsense:

For emphasizing that there is not mystery...

It is a pure question of logic, physics, and math. A quantum particle is... a particle and not a wave. A cat is a cat and not an apple.

The definition of a particle can be something that is wave-like, the only evidence you have provided are traits of particles that are used by quantum wave mechanics. Furthermore the link shows that harmonic oscillator mechanics are used in quantum mechanics and originate from classical wave mechanics.

Royston · May 9, 2012

Have a care with this statement.

What do you think the similarity of the classical oscillator equation is to the quantum wave equation?

Furthermore are you aware that an oscillator and a wave are different things?

He did say quantum oscillator, which is the analogue of a classical oscillator.

Not so much for your benefit, as you say you've studied QM however I'm happy to run through the derivation of this, but we'll be veering even more off topic. But classically (and restricting to simple harmonic motion) we have...

[math]V(x) = \frac{1}{2}Cx^2[/math] which is the potential energy of a simple harmonic oscillator.

[math]E_{kin} = \frac{1}{2}mv^2_x = \frac{p^2_x}{2m}[/math] which is the kinetic energy of the system, remembering that p = mv. So...

[math]E=\frac{p^2_x}{2m}+\frac{1}{2}Cx^2[/math] is the total energy of the system. C comes from Hooke's law i.e [math]F_x = -C_x[/math] that follows Newtons second law so [math]m\frac{d^2 x}{dt^2} = F_x = -C_x[/math]. This can be rearranged to [math]\frac{d^2_x}{dt^2} + w^2_0 x = 0[/math] where [math]w_o = \sqrt{\frac{C}{m}}[/math].

From here on it's simple to use the classical Hamiltonian function, and convert the variables to operators to construct the Schrodinger equation. If you follow through this derivation it should become clear how you get to this

[math]i\hbar \frac{\partial \Psi}{\partial t} = -\frac{\hbar^2}{2m}\frac{\partial^2\Psi}{\partial x^2} + \frac{1}{2} m w^2_0 x^2 \Psi(x,t)[/math]

This discussion doesn't seem to be getting anywhere, as you said, so I'll start a new thread and try to construct it in such a way that we have a more orderly discussion...because it is very interesting. I would also like to get some more insight on QFT (I've asked some experts elsewhere, so I hope my rudimentary understanding will be enough to kick things off properly.)

As an aside, Questionposter, a bit of friendly advice.

Please stop just grabbing tid bits of information and sticking them into discussions that are not related. It's if you're doing cursory glances at wikipedia, not bothering to understand what the terminology means, and whacking it into discussions. It's very frustrating for people trying to answer you're questions, because you're muddling things up and derailing threads, through people trying to explain to you what the terminology means, and why it's not related. Stick to short, succinct questions, understand the answer, then move on to something else, rather than jumbling stuff up. :confused: Sorry if that comes across as patronizing, that's not my intention.

Edited May 9, 2012 by Royston

questionposter · May 9, 2012

As an aside, Questionposter, a bit of friendly advice.

Please stop just grabbing tid bits of information and sticking them into discussions that are not related. It's if you're doing cursory glances at wikipedia, not bothering to understand what the terminology means, and whacking it into discussions. It's very frustrating for people trying to answer you're questions, because you're muddling things up and derailing threads, through people trying to explain to you what the terminology means, and why it's not related. Stick to short, succinct questions, understand the answer, then move on to something else, rather than jumbling stuff up. Sorry if that comes across as patronizing, that's not my intention.

What terminology are you talking about specifically? Heisenberg's and Schrodinger's math DO achieve the same experimental results if that's what you mean. And was I wrong to say a a quantum harmonic oscillator was derived from a classical harmonic oscillator to account of the nodal surfaces in atomic orbitals?

Edited May 9, 2012 by questionposter

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