This effect and results presented by Isidor Rabi were the main points of discussion at the Shelter Island Conference. Experiments using this effect to measure the proton charge radius initially showed a large discrepancy with traditional methods, sparking the “proton radius puzzle.” The experiment that discovered this effect slammed electrons into an atomic beam, then radiated the beam with microwaves, and then observed the presence or absence of current when the beam struck a tungsten foil. The strength of this effect is proportional to “the fine structure constant to the fifth, times the log of one over the fine structure constant.” On a famous train ride, this effect was calculated by subtracting a free-electron term from the self-energy of the electron. For 10 points, Hans Bethe (“BAY-tuh”) spurred the development of QED by calculating what non-degeneracy of the 2S½ (“two-S-one-half”) and 2P½ (“two-P-one-half”) states of hydrogen? ■END■
ANSWER: Lamb shift (Isidor Rabi reported measurements of the magnetic moment of the electron. The “proton radius puzzle” in the second sentence is diminishing due to more accurate spectroscopic methods, as discussed in the 2018 CODATA recommended values of the fundamental physical constants.)
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= Average correct buzz position