Physics Today: Nobel Prize winner Willis Eugene Lamb Jr died early Thursday, 15 May, at University Medical Center in Tucson, Arizona, of complications arising from a gallstone disorder. He was 94. 
Lamb was born in 12 July 1913 in Los Angeles, California. He received a BS in chemistry in 1934 and a PhD in Physics in 19358 from the University of California, Berkeley. His doctoral research on the scattering of neutrons by a crystal was directed by J. Robert Oppenheimer.
He joined the Columbia University physics faculty in 1938. From 1943 to 1951, he worked with the Columbia Radiation Laboratory. There his defense-related research focused on the problem of how to make shorter, higher-frequency microwave sources for radar.
"I was teaching a summer session course on spectroscopy at Columbia in 1945 and remember August 8, the day the bombing of Hiroshima was announced," Lamb recalled in an interview in 2000, when he received the National Medal of Science, the nation's highest scientific honor.
"In teaching this course, I read a book that mentioned that German researchers in the 1930s had thought that hydrogen atoms would respond to three centimeter-wavelength radiation, the same radiation I worked with in the lab," he said.
Because of the war, Lamb had no way to contact the German scientists, who had disappeared. But he knew how to make the necessary radiation, and in the summer of 1946 he conceived a difficult experiment to study the fine structure of optical radiation from hydrogen with very high-resolution radio-frequency resonance methods. He designed and built the apparatus with R. C. Retherford, a Columbia University graduate student.
Lamb explained: "The apparatus I used was a combination of metal and glass. You might say the hydrogen atoms went in one end and came out the other end, and in between you did things with them involving microwaves and a magnetic field. The whole thing sat on a table maybe eight feet long.
"In April 1947 — "I remember it was on a Saturday," Lamb said — his experiment succeeded. It revealed the minute but significant shift of energy in the hydrogen atom in different states.
Two months later he was invited to present his work at a historically famous conference on Shelter Island, New York; the conference was subsidized by the National Academy of Sciences to explore directions for research in the post war era.
Prior to Lamb's discovery, physicists knew that some states of the hydrogen atom had well-defined energy levels. The accepted theories predicted that certain distinct states would have precisely the same energies when the atom was activated. But physicists were puzzled when other calculations suggested that those energies might differ by tiny amounts, and the experimental evidence was unclear.Lamb's discovery of the quantum effect that became known as the "Lamb shift" led physicists to rethink the basic concepts behind the application of quantum theory to electromagnetism. His work, which became one of the foundations of quantum electrodynamics, a key aspect of modern elementary-particle physics, won the 1955 Nobel Prize in Physics.
Lamb is also well known for his theoretical research with lasers, which predicted how the intensity of a laser drops under certain circumstances. The process had been seen experimentally by William Bennett. The effect, which can be used to precisely set laser frequencies, is known as the Lamb-Bennett dip.
Lamb was the Wykeham Professor of Physics at the University of Oxford from 1956 to 1962, and he also taught at Yale, Columbia and Stanford. He joined the University of Arizona in 1974 and retired from full-time research and teaching in 2002.
Lamb wrote a series of papers, published in the Physical Review from 1947-1953 that was regarded as an immediate classic by everyone working in atomic physics, said UA physics professor William H. Wing. Wing said that when he began graduate studies at the University of Michigan in 1962, he was handed that set of Lamb's papers as a starting point for learning modern atomic physics. He did his post-graduate research at Yale, supervised by Lamb. Wing was appointed to the Yale faculty, then joined Lamb when he moved to Arizona in 1974.
Lamb's first wife, Ursula Schaefer Lamb, died in 1996. His marriage to Bruria Kaufman, a physicist he met at Columbia in 1941, ended in divorce.
"His fondest life memories were two — his years at New College, Oxford University, and his summer trips to the Lindau Nobel Laureate Meetings, a gathering of Nobel laureates and talented young students held annually at Lindau, Germany on Lake Constance. We were planning to attend the Lindau meeting this summer," said third wife Elsie Wattson Lamb, who met Lamb 27 years ago and married him earlier this year on 26 January 2008.In addition to his widow, Lamb is survived by a brother, Perry, who lives in Maine.
Related Links
University of Arizona press release
1955 Nobel Prize in Physics
Biography at Nobel Prize Foundation
Lamb's Nobel Prize Speech
