[General] Potential energies of particles and photons

Mark, Martin van der martin.van.der.mark at philips.com
Sat May 16 13:17:29 PDT 2015


John, Andrew,

The de Broglie frequency is omega_B = 2 pi v/lambda_B = gamma mv^2/hbar
It is the v^2 that killed me

Best, Martin

Dr. Martin B. van der Mark
Principal Scientist, Minimally Invasive Healthcare

Philips Research Europe - Eindhoven
High Tech Campus, Building 34 (WB2.025)
Prof. Holstlaan 4
5656 AE  Eindhoven, The Netherlands
Tel: +31 40 2747548

From: General [mailto:general-bounces+martin.van.der.mark=philips.com at lists.natureoflightandparticles.org] On Behalf Of John Williamson
Sent: zaterdag 16 mei 2015 22:12
To: Nature of Light and Particles - General Discussion
Cc: Nick Bailey; Kyran Williamson; Manohar .; Ariane Mandray
Subject: Re: [General] Potential energies of particles and photons

Aha ...

Thank you Andrew ... just re-read your last email. Was not getting why you did not get it.. Now I at least get why ... and the problem is more general so I'm sure others have it too.

The problem is model collision.

Lots of you are thinking about trajectories of things in space. To understand some things you need to think about trajectories and objects not just in space space, but also in momentum space, frequency space, rotation space and angular momentum space (to name just a few). Thinking just in space space can lead to an awful lot of confusion (as here). Sometimes it is very difficult to think past models where these work very well in many circumstances, but this is what is required here. Sometimes you need to consciously UNTHINK things in space space

Things do not resonate in space. Things do not even resonate in time (though that is better). Things do resonate in frequency - and this is where the resonance (for the bell - or for lots of sorts of quantisation) is defined. Time and inverse time have different structure and different (relativistic) properties, different scales and different limits. Getting this properly is to get relativity properly (and to get why lightspeed is such a precise limit). There is no easy shortcut or analogy to getting this  - it is just very hard. Main point here is that , for resonance, one is properly thinking of frequencies

To confuse things there are other possible "resonances" including in inverse dual-time ( as sort of angular momentum resonance) - but that is for a more advanced session. These things should really have other words to describe them. The regularity of a plane figure under rotation, for example.

Now, if the electron proton system were a little planetary system, consisting of point electron orbiting point proton you would be right. Pretty poor resonance indeed.

Obviously, though this is a reasonable model, it just is not so in reality.

The electron is not a point.

Neither is the proton (except in some simple approximations!).

Not at all. Not a bit. There is no sign of the atomic-orbital stuff in 1S states in physical chemistry (am I right Pavel?).

Now, in Hydrogen, both electron and proton DO have exactly the same de-Broglie wavelength, and hence exactly the same de-broglie frequency. Now that is a very very good resonance indeed.

Same is true for any 1S bound charge and anticharge.

Cheers,

John.

________________________________
From: General [general-bounces+john.williamson=glasgow.ac.uk at lists.natureoflightandparticles.org] on behalf of John Williamson [John.Williamson at glasgow.ac.uk]
Sent: Saturday, May 16, 2015 8:43 PM
To: Nature of Light and Particles - General Discussion
Cc: Manohar .; Nick Bailey; Kyran Williamson; Ariane Mandray
Subject: Re: [General] Potential energies of particles and photons
Hiya Andrew,

Let me jump in.

No, this is not a sensitised issue because of any specific model. It is true for a large mass, in terms of MOTION ... that. within the old Newton law approach, that approximation is a good one, but the energy is not coming primarily from motion, or sitting on a point particle, but is arising from the cancellation of field. It is part of the process of thinking about how field works at all - and that is what this whole discussion group is about.

 The process must also work for positronium, where the two masses are equal. We all need to understand how this sort of thing works because it is the stuff of physics and the stuff which we are talking about.  Now this was an interesting problem which I solved at undergrad level with a very inspiring teacher a long time ago. You gotta be lucky sometimes with you teachers!

In postronium one works with, as Martin says, the reduced mass. This is a textbook problem and can be looked up in the web or in an intermediate textbook. Bottom line is that there the potential and kinetic energies on approach to the 1S orbital are the same for electron and positron (but also for any two unit charged particles).

Looking at it from the field perspective, however, is more instructive. Turns out that what you have for two isolated charges are 1 electron and one positron with their respective masses and fields and field energy densities out to infinity.

Move gradually to 1S positronium .... here one has kinetic and potential energies using reduced mass and equal de-broglie wavelengths (obviously- but is also the same for hydrogen atom).

Where the binding energy has "come from" is not some point-particle structure, but lies in the cancellation of the external field. The integral of the field energy from the de-Broglie wavelength to infinity of the field energy density of the individual initial  electron and postron (1/2 epsilon0 E squared) is now cancelled as positrionium is neutral outside this radius. This, (not by co-incidence, it is an incidence) is exactly the potential energy part of the new system (they have gained half this in mutual K.E).

Hope this helps,

Regards, John.
________________________________
From: General [general-bounces+john.williamson=glasgow.ac.uk at lists.natureoflightandparticles.org] on behalf of Andrew Meulenberg [mules333 at gmail.com]
Sent: Saturday, May 16, 2015 8:19 PM
To: Nature of Light and Particles - General Discussion; Andrew Meulenberg
Subject: Re: [General] Potential energies of particles and photons
Dear Martin,
Comments below:

On Sat, May 16, 2015 at 7:54 PM, Mark, Martin van der <martin.van.der.mark at philips.com<mailto:martin.van.der.mark at philips.com>> wrote:
Dear Andrew,
I have just read your email again, but now not on my Iphone but on my laptop. It is much easier that way.

You are completely missing the fact that you are using the Born-Oppenheimer APPROXIMATION to the atom structure. This is the beginning of all the confusion you load on yourself (and the reader) as a consequence.
http://en.wikipedia.org/wiki/Born_Oppenheimer

At the level of my concern, the B.O. approx is fine. Please identify, in the arguments below, where it would be a limitation.

The proton is not infinitely massive, and in the H-atom it is rotating around/oscillating against the electron just as much, in terms of its momentum as is the electron against the proton. As I said before, the momenta of electron and proton are exactly equal, and so are their de Broglie wavelengths. The electron and proton are quantum mechanically in tune! The 2-body problem can be translated into a 1-body problem using the reduced mass.
http://en.wikipedia.org/wiki/Reduced_mass

I believe that you are sensitized to this issue because it is part of your model. An issue that I can accept, but am not convinced of its importance. I consider the synchrony of the proton and electron (equal orbital frequency) to be based on Newton's 3rd law, not on resonance. Because the deBroglie wavelengths are equal, the proton completes one deBroglie wavelength cycle in many electron orbits. This does not appear to be good resonance.

The electric potential of the proton is meaningless against a neutral object, but against a charged object, also having such a potential (let the word sink in... "potential"... it is nothing until...) the two may repel or attract. It is not one or the other, it is both.

I think that we may be saying the same thing here. The electric potential of the proton is its potential to do work on another charge. I use the word 'ability' rather than 'potential'. I believe that the meaning is the same. The important point, which I think you also made, is that the work done may not be from the potential at all, e.g., the work done on charging a van der Graaff accelerator is against the potential.

Any loss of the energy of a closed system comes from the system as a whole, and the system finds a new balance in doing so.

I agree with this statement, if it is not used to be exclusive.

The way you are talking about the hydrogen atom violates Newton's 3rd  law.
http://en.wikipedia.org/wiki/Newton%27s_laws_of_motion

It is interesting that I had an argument with one of my coauthors earlier this evening on this very point. The force on the proton and electron are equal (and in opposite directions). Thus, since work is force times distance (W = F*d), the work of a decaying atomic electron is being done by the proton. It is moving the electron; the electron is not moving the proton (to the approximation I am making). Also the electron is not moving itself. You could say that the work is done by the E-field, not by either particle alone. However, you would not be correct, since the field comes from the particles.
In the interaction between an electron and positron, as they get close enough together, their masses should increase when their velocities approach the speed of light. They do not, because their residual masses decrease at the same rate. This allows energy to be conserved.The relativistic mass is electromagnetic (AC or alternating) in nature. The residual mass is being converted into EM energy. At some point, all of the 'DC' mass (and DC charge) is gone and only photons remain. If this were not so, energy could not be conserved.

In the interaction between an electron and proton, as they get close enough together (s-orbitals), the electron mass should increase when its velocity approaches the speed of light. It does so. Thus, it is not using up its potential energy in the process. Since energy is conserved, and a photon is emitted (from the e-p dipole, but mainly from the electron), the excess electron mass (relativistic) must come from the proton. QED
Since the proton is part of the system, we could correctly say that the relativistic electron mass comes from the system. However, that does not change the proof that the proton provides the mass energy for the electron decay.

I hope this helps. Please stop confusing the poor students.
Cheers, Martin

Physics has tried to simplify and codify its teaching for so long that important concepts seem to have been forgotten and therefore are not considered when looking at new concepts.
Andrew



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