Quantum fluctuation and quantum mysticism

[friend]

Since so many other university professors are using virtual particles as at least an analogy to describe the math, then perhaps you have (or should write) an article that explains why they use them (what math they are used to explain) and why they are wrong. That would be very instructive. Thank you.

 

[A. Neumaier]

denouncing virtual particles as never appropriate to use

Here you misinterpret me; I never said that. Instead I said:

It is appropriate to use them as visual aids.
But they are treated in much of the world of nonphysicists (including many wikipedia articles) as something dynamical, which is pure science fiction.

Let me emphasize:

• It is appropriate to use them only as visual aids, not in any other way.
• What really counts is only the math.

Without properly understanding the latter, any talk about virtual particles or vacuum fluctuations is likely to be highly misleading. If a physics professor is using the words, you should look for the math behind it and try to understand that. Only if you understood the latter you can claim that you understood the professor.

 

[A. Neumaier]

perhaps you have (or should write) an article that explains why they use them (what math they are used to explain) and why they are wrong. That would be very instructive.

I had done this already and had announced it on this forum a few days ago in a thread to which you contributed. But you were apparently too lazy to study the links, or too occupied with your own ideas about the matter.

Or didn't you take me seriously because you didn't know that I was a university professor?

I won't respond to you anymore until I see clear signs that you read all I wrote about the matter and linked to in the last few days.

 

[friend]

Yes, I am trying to understand better how to use t

I had done this already and had announced it on this forum a few days ago in a thread to which you contributed. But you were apparently too lazy to study the links, or too occupied with your own ideas about the matter.

Or didn't you take me seriously because you didn't know that I was a university professor?

Probably a little of all of the above. I did look at your article, and IIRC it showed that virtual particles were synonymous with Feynman diagrams. I did not see how it related to the issue of usability for theory development. If you would be so kind, could you tell me what is so speculative or wrong about my perspective in post 32 of this thread? I really wasn't using any dynamics there, ONLY that virtual particles are identical to real particles but recombine after a short time (the most common description of them). I thought that was pretty obvious, and it's key to my understanding. Now would be a good time to clear up any misconceptions. Thank you.

 

[friend]

... then the most immediate consequence would be a bare particle would recombine with one of the virtual pairs created in the vacuum nearby the bare particle, leaving the virtual partner real until it recombines with one of some other virtual pair produced nearby. In this view of things, the actual real particle is continually being traded among the nearby virtual pairs being produced in the vacuum. ... It's just a restatement that virtual pairs separate and come back together with their partners or with something identical with their partners. ...

This goes further. It seems the accelerating expansion of space results in particle creation (by ripping apart virtual pairs, or so the story goes). Since both the disentanglement of the virtual particles and accelerated expansion exist in conjunction, it's hard to say which is the cause and which is the effect. If one must always accompany the other, then the question must be asked. Does recombination (re-entanglement) of a real particle with an antiparticle cause space contraction? Then would a bare particle recombining with one of the virtual pairs produced nearby (see above) cause space contraction close by compared to space expansion further away (as the unpaired virtual partner drifts away and is disentangled)? Could this result in the curvature we see in gravity? I've already mentioned (elsewhere) where some theorists are considering how the entanglement of virtual particles cause gravity.

 

[samalkhaiat]

Weinberg's three volumes on quantum field theory are an example of books where not a single reference to virtual particles is made. Mentioning them is not needed since they don't have an existence except in some people's mind.

How sure are you? See
Weinberg Vol. 1
13.2 Virtual Soft Photons.
13.3 Real Soft Photons.

 

[A. Neumaier]

How sure are you?

I was sure until you pointed this out. Thanks a lot. I won't make again the claim that Weinberg's book doesn't mention virtual particles, and corrected my statement.

Indeed, he uses virtual soft photons in his perturbative discussion of infrared divergences and how to get rid of them. His virtual photons appear only in calculations that lead to obviously unphysical divergences, therefore are unphysical themselves.

The mathematically preferable, virtual-particle free version of this via coherent states is not in the book, not even referenced.

 

[vanhees71]

Well, here are some references:

P. Kulish and L. Faddeev. Asymptotic conditions and infrared divergences in quantum electrodynamics. Theor. Math. Phys., 4:745, 1970.
http://dx.doi.org/10.1007/BF01066485

T. W. B. Kibble. Coherent Soft‐Photon States and Infrared Divergences. I. Classical Currents. Jour. Math. Phys., 9:315, 1968.
http://dx.doi.org/10.1063/1.1664582

T. W. B. Kibble. Coherent Soft-Photon States and Infrared Divergences. II. Mass-Shell Singularities of Green's Functions. Phys. Rev., 173:1527–1535, 1968.
http://dx.doi.org/10.1103/PhysRev.173.1527

T. W. B. Kibble. Coherent Soft-Photon States and Infrared Divergences. III. Asymptotic States and Reduction Formulas. Phys. Rev., 174:1882–1901, 1968.
http://dx.doi.org/10.1103/PhysRev.174.1882

T. W. B. Kibble. Coherent Soft-Photon States and Infrared Divergences. IV. The Scattering Operator. Phys. Rev., 175:1624, 1968.
http://dx.doi.org/10.1103/PhysRev.175.1624

N. Papanicolaou. Infrared Problems in Quantum Electrodynamics. Phys. Rept., 24:229–313, 1976.
http://dx.doi.org/10.1016/0370-1573(76)90003-X

M. Swanson. Reduction formulas for quantum electrodynamics. Phys. Rev. D, 25:2086–2102, 1982.
http://dx.doi.org/10.1103/PhysRevD.25.2086