Atom as a "Dressed" Nucleus

Question

Referee this paper: arXiv:0806.2635

Please use comments to point to previous work in this direction, and reviews to referee the accuracy of the paper. Feel free to edit this submission to summarise the paper (just click on edit, your summary will then appear under the horizontal line)

(Is this your paper?)

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This paper deals first with a "second atomic form-factor" $f_n^{n'}(\mathbf{q})$, which is absent in textbooks: the differential cross section of scattering a fast charged projectile from an atom is proportional to $$d\sigma_n^{n'}(\mathbf{q}) \propto |Z\cdot f_n^{n'}(\mathbf{q})-F_n^{n'}(\mathbf{q})|^2d\Omega.$$

Text-books consider the atomic nucleus to be in the atomic center of mass, so their $f_n^{n'}(\mathbf{q})$ is equal to $\delta_n^{n'}$ which is wrong.

For elastic scattering ($n'=n$) the second atomic form-factor describes the positive charge "cloud" around atomic center of mass due to the nucleus motion. This "cloud" and its physics are completely analogous to the negative charge "cloud" known to everybody from QM.

For inelastic scattering ($n'\ne n$) the second atomic form-factor describes the amplitude of atom excitation due to transferring a momentum $\mathbf{q}$ while "pushing" the nucleus. Its physics is completely analogous to the amplitude of atom excitation due to transferring a momentum $\mathbf{q}$ while "pushing" the atomic electrons.

The positive "cloud" size depends on the atomic state [math]$n$[/math] and can be made rather big. This is how fast charged projectiles "see" an atom as a target in the first Born approximation (i.e., when the target is not polarized with a slow projectile). Although unknown, this effect seems natural.

Atom is a compound system and the nucleus is bound in it due to its permanent interaction with atomic electrons. Neglecting this interaction gives wrong physics - no positively charged "cloud" in the elastic channel and no atom excitation under extremely high transferred momentum $\mathbf{q}$. Perturbative corrections to the latter description are big and are analogous to the infra-red divergent corrections in QED. That is why I propose in a second part of my article a new construction for an electron permanently coupled to the electromagnetic field. I build it by analogy with atomic description and call this construction an "electronium". This solution has no IR problems at all and an inclusive picture becomes natural. The Bloch-Nordsieck approximation is thus explained and quantitatively justified. I think such a construction and its physics is what we need in QED. That's a brief summary.

Answer 1

Since this paper is motivated by its potential applications to QED, and since its statements about QED are highly misleading, I review just these statements. Those interested in the dressed nucleus itself should form their own opinion about the paper.

I quote from version v9.

the self-interaction in QED remains, infinite corrections persist, and renormalization ideology leads to a rather bizarre notion of bare pointlike particles with infinite physical parameters. (p.1)

This is not true; for example, QED in causal perturbation theory is free from all these problems.

Implementation of this idea in QED and in QFT removes the problems of appearing infinities. (p.2) 

Where is this proved? Section 4 only provides analogies, which are not enough to substantiate the claim. Scientific standards would require for such a claim at least to reproduce one of the standard successes of QED (e.g., a prediction of the anomalous magnetic moment) for the proposed electronium model.

 Thus, the problem of IR and UV divergences is removed in QED at one stroke by using the notion of an electronium (p.15)

These problems seem to be removed in electronium theory, but since electronium theory is neither gauge invariant nor Poincare invariant, it is a theory very different from QED. It is unlikely to have physical relevance.

The part analyzing the toy models might be useful, but they do not substantiate the statements made about QED. The author should cut out all claims and speculations about QED or at least qualify it according to what he actually proves. 

Comments

If QED is constructed on purpose as the electronium constructed (a compound system for the real electron and EM field), then these problems are absent by construction. This construction is not difficult to understand, but much more difficult to finalize.

It is not "very different from QED" if we speak of the final results: in QED every external electron line radiates it own soft photons.

One can obtain estimations for the Lamb shift and for the anomalous magnetic moment. They were obtained in a seminal paper of T. Welton. The anomalous magnetic moment turns out to be of good dimension and order of value, but of the opposite sign. This is due to non-relativistic model not containing the electron-positron degrees of freedom.

The electronium model is similar to the atomic model, but nobody blames the latter for lacking the Poincaré and gauge invariance. Your blame is ridiculous.

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This is an irrelevant sideline to the main claims of the paper, and must not bias your review. The main claim is about the behavior of scattering off atoms.

Let me emphatically repeat: this is not a paper about renormalization. It is a paper about form factors. The renormalization language is not useful, not accurate, but not the topic of the paper, so it should not make any difference in this review. This review is only useful if it explains whether the "second form factor" is useful, accurately computed, and so on.

I could find you wrong statements here and there you could pick on in nearly any paper. This is not the point of a scientific review. Review is about the main content of the paper, not about biases or beliefs that are stated on the sidelines.

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So then these irrelevant sideline claims should better be left out from the paper. Why are they there in the first place then, if they do nothing but distract from the main topic? If such claims are included, they can legitimately be judged too.

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@Dilaton and Arnold: My claims are not so radical. I say "I think the relativistic Hamiltonian of Novel QED should be constructed in the same spirit." You may think it is a wishful thinking, but the problems of self-induction are proposed to be eliminated by construction. So what can you expect? They reappear?

And these atomic and electronium constructions, they do serve to point-out another direction of theory building. I wanted to demonstrate it. They are relevant!

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If submitted to a high quality journal, such statements would be grounds enough to require revision of a paper, if not already a rejection. You are welcome to write a second review about the other aspects.

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That you made some claims that are correct is not excluded by my review.  But I highlighted three claims that you made without justification, that are enough to reject the paper in its present form.

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It has been rejected, Arnold, but not because of QED claims! Because nobody believed in "positive clouds" in atom, i.e., well before thinking everything over.

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@ArnoldNeumaier: You are free to review as you like, but this is not exactly a journal--- we aren't responsible for putting the paper out and defending every statement in there, the paper is already out, and we want to let a reader know what is accurate in the paper and what is inaccurate.

You pointed out what is inaccurate in the paper, I agree with you regarding this. But the problem is that the things that are inaccurate are minor sidelines, you didn't touch the main claim of the paper regarding the positive clouds business, which looks interesting and important to me (if it is accurate, which I need to check, I didn't do it yet) regardless of the false speculative claims in the paper.

Speculative claims to me always have a lower importance. They are like the bullshit you read in introductions and conclusions, they are not the content of the work. There are a lot of silly philosophical disputes in these introductions and conclusions. The reason I didn't like this review is because it is not reviewing the main calculation in the paper.

When I read this review, I want to know if the form factor calculation is correct and accurate. I still don't know any more now than when I started to read the review, so I don't think the review is informative. Honestly, everyone already knows that the claims about QED are not mainstream and if you look in detail, you also see that they are not justified. These serve only as motivation in this paper.

It is fine to criticize the reformulation nonsense, sure, but that does not really review the paper. But I agree that you are saying correct things, so I make no downvote.

The proper paper to place a criticism of "QED reformulation" is the one Vladimir did not even put up for review--- the one you linked in the chat discussion. This one has a mistake in the reformulation of QED, a clear mistake, and it gives wrong answers that are in dipole approximation throughout, and cannot be pulled out of dipole approximation, and also gauge noninvariant for much the same reason. That paper can be imported to reviews and voted on and reviewed negatively properly. But the remaining papers are doing other calculations which don't obviously depend on the false beliefs of the author regarding the formulation of QED.
 

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Vladimir pointed out that what Arnold critisizes are not minor sidelines, it is a main point he wants to make backed up by his toy model. I agree with Arnold, slinging around broad overreaching (negative) claims about other peoples work without backing them up in a scientifically appropriate way is very low popular media standard. Arnold is exactly right by pointing the errors of these broad overreaching claims out.

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@Dilaton: I didn't even read the inflammatory introduction when I read the paper, I started with the section "Second Atomic Form Factors" where there was some real content (some calculation). The introduction makes false claims, but they are empty words, and anyone coming here for a review will already know the consensus regarding renormalization and QED, and their only question will be about the details of the form factor calculations.

Beginning on page 11, there is the "electronium" model, in which I know for sure that there is a mathematical error. The electronium model doesn't work for mixing of radiation and atomic modes outside the dipole approximation. In the dipole approximation it looks ok, but VK claims it is valid for describing electrons (electronium is a dressed electron in Kalitvianskese), and it is certainly NOT valid, and this section is worthy of downvotes because of the technical error there (but I don't remember this section existing when I read the paper originally, I only remember the atomic form factors discussion which was interesting and seemed possibly correct).

The paper here seems to be a union of two papers, one possibly correct paper about atomic form factors, and another incorrect paper about electronium interactions. Perhaps both are incorrect, I don't know, and the review didn't tell me. So it's an extremely partial review, which only tells me that the author makes sure to piss other people off by saying things that are widely believed to be incorrect. I already knew that too. But I would like to know what the atomic form factors are, if they are right in the textbooks, or if VK has given the right form.

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"In the dipole approximation it looks ok, but ...", "and cannot be pulled out of dipole approximation...", "and also gauge noninvariant..."

If it is not correct in a "multipole" case, one can generalize the model. This all needs carefully studying before judging. Including your "gauge non-invariance" statement.

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After reading your edited "review", Arnold, I understood that you do not want to know my motivation at all because, according to you, there are no problems in QED. So your review it just a statement that everything in QED is already OK and I, stupid, tried in vain to make some improvements.

Thanks to you and to the like, I have no right to edit the summary to be better understood (and to correct elementary typos). This situation on this site shows how academia eliminates freedom of speech.

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All authors who do not yet have 500 rep share the problem of editing the summary of their own paper, as not everybody can create submissions at present.

If you still have a version of the summary off-site, you could correct and edit it there, and afterwards post it in a  temporary comment to be exchanged with the current summary.

You know that your talkings about "freedom of speach" are ridiculously off the mark...

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I know your motivation, namely that you believe QED is not OK and needs improvement. 

I don't share your motivation since in causal perturbation theory, QED is fully OK. No infinities, no bare constants, no discarded terms anywhere. Just two physical parameters $m$ and $e$ with a measurable meaning. The only unsettled problem about QED is the question of making nonperturbative sense of the series in powers of the fine structure constant.

You quote Dirac to support your views, but he is long dead, and unlike you he couldn't read Scharf's book, which removes all of his concerns.

There are a few others sharing your beliefs, notably Chris Oakley and Eugene Stefanovich. The latter's book is not referenced by you although it is (apart from some crazy misjudgments about relativity) a far more competent alternative approach to QED than yours - just very messy, but yours is virtually nonexistent, and if you would do serious work on it you'd run into similarly messy computations. That why nobody else is interested in trodding along such a path.

But though you had plenty of space here on PO to express your motivations and beliefs - probably every reader here knows your views - you still complain about lack of freedom of speech ...

... because you are not allowed to edit your summary! Not your summary here needs correction, but the papers you wrote! The errors are in there!

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Your Scharf postulates all results obtained before him. He cannot use the equations (unlike P. Dirac), but he uses their solutions! The equations are acausal in his opinion and he postulates their solutions instead. And here we are. End of the science.

Eugene Stefanovich uses renormalization perturbatively by removing "bad" terms.

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Only your sloppy way of reading the literature and your habit of putting down highly regarded scientific work is the end of science. This will be my last comment to your vain accusations.

There are good reasons why Scharf's approach is called causal perturbation theory. There is nothing acausal in his work. He constructs in the second edition of his QED book the field operators in the Heisenberg picture, which provides a complete causal, Poincare invariant and gauge invariant dynamics for all observables on the perturbative level.

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Scharf obtains nothing new, absolutely. New is how he "proves" that non-zero is zero. People knew this well before him - they used zeros "from a physical requirements" (QED, Berestetsky, Lifshits, Pitaevski, renormalization "on the go" (or "en route")). Scharf also appeals to "physical requirements" to "obtain" the same zeros from non-zeros. What an advancement!