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 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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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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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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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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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!