Abraham Pais

Born on 19 May 1918 in Amsterdam, Abraham “Bram” Pais excelled both as a particle physicist and a historian of science. He earned bachelor’s degrees in physics and mathematics at the University of Amsterdam in 1938. In 1941 he received a PhD from the University of Utrecht—the last PhD the university awarded to a Dutch Jew during the Nazi occupation. Pais survived the war thanks to Tina Strobos, a friend who arranged hiding places for him and other Dutch Jews. Following the war Pais worked briefly with Niels Bohr and invented the term lepton. In 1946 he moved to the US and, over the next few decades, made several major particle-physics advances. In 1952 he used the strong interaction to explain the process of “associated production,” in which certain particles are produced rapidly but decay slowly. He then worked with Murray Gell-Mann to explain a mysterious particle, now known as K_s, as a quantum mechanical mixture of another particle (the K₀) and its antiparticle. In 1963 Pais moved to Rockefeller University in New York, where he would remain for the rest of his career. In that later phase he began to focus on history and biography. His books include Inward Bound: Of Matter and Forces in the Physical World, and Subtle is the Lord: The Science and the Life of Albert Einstein, which is the favorite Einstein biography of many physicists. He died in 2000 in Copenhagen at age 82. You can read the Physics Today obituary written by Howard Georgi. Pais contributed several articles to Physics Today, including an analysis of the media’s treatment of Einstein and a particle-physics primer for the magazine’s 20th anniversary in 1968. (Photo credit: AIP Emilio Segrè Visual Archives, Physics Today Collection)

Date in History: 19 May 1918