Willis Eugene Lamb Jr. (/læm/; July 12, 1913 – May 15, 2008) was an American physicist who won the Nobel Prize in Physics in 1955 "for his discoveries concerning the fine structure of the hydrogen spectrum."

For theoretical work on scattering of neutrons by a crystal, guided by J. Robert Oppenheimer, he received the Ph.D. in physics in 1938.

[2] He worked on nuclear theory, laser physics, and verifying quantum mechanics.

"[9] Lamb was also openly critical of many of the interpretational trends on quantum mechanics[10] and of the use of the term photon.

[11] In 1939 Lamb married his first wife, Ursula Schäfer, a German student, who became a distinguished historian of Latin America (and assumed his last name).