I wonder if there is an intuitive way to obtain the $\frac{\alpha}{2\pi}$ correction to electron's $\frac12 (g-2)$ just like how Bethe estimated the Lamb shift?
Here is an attempt by Drell & Pagels (dispersion relation) Link
I wonder if there is an intuitive way to obtain the $\frac{\alpha}{2\pi}$ correction to electron's $\frac12 (g-2)$ just like how Bethe estimated the Lamb shift?
Here is an attempt by Drell & Pagels (dispersion relation) Link
T. Welton gave an estimation in 1948. It was of good order of magnitude but of the opposite sign, apparently, because his estimations were non-relativistic and did not take into account virtual pairs. https://docs.google.com/open?id=0B4Db4rFq72mLOTE4ZTQ0NzUtMzZmNy00ZDU1LTgwNDQtMjU4NDUwMDAyMDg0