Lamb, Willis E. And Robert C. Retherford, “Fine Structure of the Hydrogen Atom by a Microwave Method”. In Physical Review, volume 72, number 3, August 1, 1947, pp 241-243, in the issue of pp 189-261. Fine copy in the original wrappers. $1000
_____. Another copy, not quite as nice. Very Good. $750
The Lamb Shift and the beginning of quantum electrodynamics. Lamb won the Nobel Prize in Physics in 1955 for his discoveries related to the Lamb shift.
- “...it became clear that a new chapter in physics was upon us." A. Pais, Inward Bound, relating Lamb delivering his report at Shelter Island, p 451.
“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.”
“On Lamb's 65th birthday, Freeman Dyson addressed him as follows: "Those years, when the Lamb shift was the central theme of physics, were golden years for all the physicists of my generation. You were the first to see that this tiny shift, so elusive and hard to measure, would clarify our thinking about particles and fields."--Wikipedia on the Lamb Shift
Elsewhere Dyson referred to the best place for experiment in physics to be in the world at that time was Columbia, with Rabi in charge, and where Lamb (Ph.D. under Oppenheimer) was doing his work on the hydrogen atom. In an interview Dyson remarked that hydrogen was the “most deeply explored” object in science, and that “if you don't understand the hydrogen atom, then you don't understand anything”. When Lamb—using the new microwave measuring capacities—found that there was a discrepancy between theory and experiment regarding the hydrogen spectrum it was found to be, well, “deeply disturbing”.--quotes from Freeman Dyson on https://www.webofstories.com/play/freeman.dyson/64
- This paper reprinted in Quantum Electrodynamics edited by Julian Schwinger (1958) paper 26.