What is Lamb shift: Definition and 16 Discussions

In physics, the Lamb shift, named after Willis Lamb, is a difference in energy between two energy levels 2S1/2 and 2P1/2 (in term symbol notation) of the hydrogen atom which was not predicted by the Dirac equation, according to which these states should have the same energy.
Interaction between vacuum energy fluctuations and the hydrogen electron in these different orbitals is the cause of the Lamb shift, as was shown subsequent to its discovery. The Lamb shift has since played a significant role through vacuum energy fluctuations in theoretical prediction of Hawking radiation from black holes.
This effect was first measured in 1947 in the Lamb–Retherford experiment on the hydrogen microwave spectrum and this measurement provided the stimulus for renormalization theory to handle the divergences. It was the harbinger of modern quantum electrodynamics developed by Julian Schwinger, Richard Feynman, Ernst Stueckelberg, Sin-Itiro Tomonaga and Freeman Dyson. Lamb won the Nobel Prize in Physics in 1955 for his discoveries related to the Lamb shift.

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  1. Francisco Alegria

    A Quadruple Integral in the Lamb Shift

    The analytical computation of the shift in energy level of electrons in atoms due to quantum electrodynamics is carried out using perturbation theory. In particular, the fourth-order contribution is given in five different terms. One of them, usually called "Electron Self Energy", leads to seven...
  2. H

    A Why is gauge invariance important in quantum mechanics?

    I bought a paper written by Kuo-Ho Yang (gauge transformations and QM) in which i read this: since Lamb [1] asserted that in order to describe the interaction of a bound system with external time-varying fields to the lowest order and in the long wavelength approximation one should use an...
  3. R

    I What is the connection between the Lamb Shift and the g factor?

    German Wikipedia mentions that the g factor is one of the causes of the Lamb Shift. It does not say why and I am trying to find a connection between these two things. Any ideas?
  4. R

    Good literature needed (QFT topics)

    Summary:: Trying to find good books so that I can continue writing my paper about the vacuum Hello fellow physics enthusiasts, I require your support to find good and scientific literature about: Lamb Shift Vacuumpolarisation Zero point energy It can be a long source too, so don't be afraid...
  5. Z

    I How to calculate the Lamb Shift in Hydrogen?

    This recent article (https://www.quantamagazine.org/physicists-finally-nail-the-protons-size-and-hope-dies-20190911/) on the size of the proton left me with a couple of confusing questions: 1/ Is the amount of the lamb shift completely determined by Feynman diagrams or is "it spends part of its...
  6. A

    A Do QED effects make a huge change to the position of the electrons?

    In https://en.wikipedia.org/wiki/Lamb_shift about the lamb shift, it's mentioned that the change in the electron's frequency due to QED effects (vacuum polarization and self-energy correction) is about 1 GHz, which would translate to an energy change of hf = 6.63E-25 J. This is 3E-7 times of the...
  7. A

    A Can we create a random variable using QED effects?

    Quantum Electrodynamics (QED) has some observable effects such as the lamb shift, which is mainly caused by the vacuum polarization and the electron self-energy. These effects contribute to the "smearing" of the electron in an unpredictable manner, other than the uncertainty we already have...
  8. A

    A How, and in what atoms does the Lamb shift occur?

    The Uehling potential due to vacuum polarization by virtual electron-positron pairs is said to be the dominant contribution — 205.0073 meV — to the Lamb shift between the 2P1/22P1/2 and 2S1/22S1/2 states of muonic hydrogen. In the Wikipedia page (https://en.wikipedia.org/wiki/Lamb_shift), it is...
  9. R

    I Exploring the Lamb Shift: G-Factor & Angular Momentum

    Good day dear forum, greetings from Argentina. I am studying the Lamb Shift, which says that in the atomic orbitals, an upward energy shift occurs due to an interaction of the electron with itself. This means that a level s can have an energy slightly greater than a level p. So far so good, but...
  10. neilparker62

    I Exploring the Ground State Lamb Shift: Advances and Controversies

    What exactly is the so-called "Ground State Lamb Shift". It seems to have been an 'in vogue' quantity up till 1995 or so - then vanished from the literature ?? It's the 'self energy' or something like that of an electron in H 1S orbital. A scientist (at NIST) told me it's a term that has gone...
  11. A

    I Lamb shift and the QFT vacuum....

    I think I already know the answer to this, but I'm looking for a source: Can the Lamb shift be explained entirely in terms of radiative corrections due to the self-interaction of the hydrogen's electron with its own EM field? That is, is it necessary to reference vacuum polarization or related...
  12. blue_leaf77

    Quantum Which books discuss the Lamb shift correction in atomic energy levels?

    What will you suggest someone for books which provide discussion on the Lamb shift (QED correction) of atomic energy levels?
  13. W

    Has anyone experimentally measured the Lamb shift in Antihydrogen?

    I could only find abstracts for proposals of methods that could accomplish this. I don't have any subscriptions to journals so I can't read the papers. Also while I'm on the subject, the energy levels of antihydrogen should be the same as hydrogen right?
  14. E

    Exploring the Lamb Shift and its Impact on Electron Mass within Atoms

    Lamb shift proved that within an atom the energy level of electrons changes with changes in orbital position. Given that energy and mass are related (or “one and the same” according to some texts) does this mean that within an atom electron mass varies? And if so does this not contradict...
  15. K

    Lamb shift and creation of mass

    A 2s electron in a hydrogen atom has more energy than a 2p electron. Quantum field theory says this is because the 2s electron interacts with itself by emitting and absorbing a photon.But what if the proton and the electron carry a charge which is always repulsive.Then a 2s electron which is...