Talk:Lamb shift/Archive 1

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You do not define k, and the quantity delta r in eq 1 does not appear in eqs 2 or 3. Presumably k=0 when delta r =0. —The preceding unsigned comment was added by 65.130.158.95 (talk • contribs) 09:19, 9 June 2005.

the delta-r is approximate and conceptual, not necessarily an exact metaphor. 12.178.36.25 17:32, 8 December 2006 (UTC)

Is there a reference for "smearing out of the electron" -- I saw this on hyperphysics, also but not in any textbook on the Lamb shift. -- QED says the electron is a mathematical ideal point and so this statement seems at odds with best-accepted physical theory. 12.178.36.25 22:39, 29 November 2006 (UTC)

Aha. Starting at the first QED correction above tree-level, the point-like electron's form factors of F_1() = 1, and F_2() = 0 -- receive small corrections. (Currently my references are in momentum-space, not in terms of spacial coordinates, so I hesitate to copy these textbook answers simply because k is often used for momentum in QED which is not the case here.) The result is that the high-order QED calculations resemble first-order QED calculations as if the electron were not point-like. How to explain this in encyclopedia-talk is a bit tricky. I would guess a whole section on "Modern (QED) Explanation" would be needed. The k() function which puzzled the other user was a simple numerical factor resulting from the geometry since only for l = 0 does the electron and nucleus closely interact. 12.178.36.25 17:32, 8 December 2006 (UTC)

Clarification, laymanization?

Why they should have the same energy? Why does interaction with virtual photons change their energies? Why does this interaction influence their engergies differently? Does this have anything to do with the shape of the orbitals? (Their lengths?) —Preceding unsigned comment added by PAStheLoD (talk • contribs) 18:47, 5 March 2010 (UTC)

The .svg diagram is messed up

it doesnt render properly thumbnailed —Preceding unsigned comment added by 74.88.16.86 (talk) 10:59, 23 January 2011 (UTC)

Diagram has incorrect quantum numbers

In the diagram, the 2s and 2p states are given the quantum number n=1. Should be n=2. —Preceding unsigned comment added by 171.66.51.148 (talk) 18:37, 3 March 2011 (UTC)

External Links

Have updated the Lamb-shift link to Web of Stories and removed the dead link tag as the link was still fully functional. Fitzrovia calling (talk) 11:06, 26 May 2011 (UTC)

first sentense

The shift isn't in QED, it is in nature. The explanation of the shift is in QED. David R. Ingham (talk) 04:09, 3 July 2012 (UTC)

Bethe vs. Welton

The article as it stands has several unrelated explanations of the origin of the shift in different places.

The first explanation, due to Welton, was that vacuum flucuations are responsible.

The second explanation, due to Bethe, repudiates Welton, and is different and more difficult to understand. It would require an expert to properly explain it.

Since these explanations are not compatible, they should either be presented as competing explanations, or the Welton explanation should be presented only as history. BruceThomson (talk) 05:13, 25 August 2012 (UTC)

I can't understand the Welton explanation. 178.39.122.125 (talk) 00:59, 24 August 2016 (UTC)

References

on which page can see the resultant formula, pls?

on which page can see the resultant formulas, pls? Just now I read through the book of Bethe but can not find such clear formula,

  delat E  ~  alpka^5/ n^3  — Preceding unsigned comment added by 2606:A000:95C1:7200:EC3C:AD1C:56ED:58E4 (talk) 18:28, 28 May 2014 (UTC) 

1 vs 0.7 G

"This shift is about 1 GHz, very similar with the observed energy shift."

the observed is 1Ghz, but use the calculated value of the expression above this sentence is not 1G but 0.7 Ghz. The two values has a remakable difference. — Preceding unsigned comment added by 2606:A000:95C1:7200:9152:B628:2EBA:8148 (talk) 03:34, 20 June 2014 (UTC)

Removed non-notable aside

I removed this:

Recently, in the framework of quantum mechanics (rather than QED), Wei simply explained the Lamb shift as the effect of relativistic correction of the kinetic energy, but the calculated result of the Lamb shift was only 41% of the measured value. However, this result reminds us that if we had calculated the relativistic correction of kinetic energy carefully, we should have predicted the shift before Lamb discovered it experimentally.

I removed this. It's nice, but it's not in the main stream of things. There may be many ways to get a partial or indicative results using heuristics; we should restrict ourselves to those with historical profile or textbook quality.

On top of this, I don't quite see how a relativistic correction would help; the Lamb shift (1947+) already builds on top of the large (fine-structure) relativistic correction of the pure Schroedinger theory, which was worked out by Dirac et al 20 years earlier. Is there really a second, much smaller relativistic correction? 178.39.122.125 (talk) 01:11, 24 August 2016 (UTC)

Lamb shift and proton charge radius

A subsection explaining the role the proton charge radius plays in the Lamb shift is required. Urhixidur (talk) 12:33, 22 November 2019 (UTC)

What should we think of E.T. JAYNES point of view explaining the uselessness of alleged zero-point energy quantum field fluctuations to model the Lamb shift effect?

PROBABILITY IN QUANTUM THEORY https://bayes.wustl.edu/etj/articles/prob.in.qm.pdf E. T. Jaynes 7/8/1996

" § IS ZERO-POINT ENERGY REAL?

There is a widespread belief that ZP fluctuations are real and necessary to account for all kinds of things, such as spontaneous emission, the Lamb shift, and the Casimir attraction effect...

...A radiating atom is interacting with an electric field of just the magnitude predicted by the zero-point calculation; but this is the atom's own radiation reaction field...

...In 1961 Feynman suggested that it should be possible to calculate the Lamb shift from the change in total ZP energy in space due to the presence of a hydrogen atom in the 2s state; and in 1966 E. A. Power gave the calculation demonstrating this in detail. How can we possibly resist such a weight of authority and factual evidence?

As it turns out, quite easily. The problem has been that these calculations have been done heretofore only in a quantum field theory context. Because of this, people jumped to the conclusion that they were quantum effects (i.e. effects of field quantization), without taking the trouble to check whether they were present also in classical theory. As a result, two generations of physicists have regarded the Lamb shift as a deep, mysterious quantum effect that ordinary people cannot hope to understand. So we are facing not so much a weight of authority and facts as a mass of accumulated folklore.

Since our aim now is only to explain the elementary physics of the situation rather than to give a full formal calculation, let us show that this radiative frequency shift effect was present already in classical theory, and that its cause lies simply in properties of the source field (1), having nothing to do with field fluctuations."

Shouldn't JAYNES' article deserve a quotation in WIKI lamb-shift article accompanied with the appropriate comments?