Silvan Samuel Schweber, who died on 14 May 2017 in Cambridge, Massachusetts, was a theoretical physicist by training and an accomplished historian of physics who contributed major works on the evolution of theoretical physics from James Clerk Maxwell through Richard Feynman.

Silvan Samuel Schweber

Born in Strasbourg, France, on 10 April 1928, Schweber grew up in a Jewish family that soon felt the approaching danger of Nazism. Fleeing to Vichy, the family found temporary and fragile respite; his mother succeeded in rescuing several family members and some unrelated Jews who had been arrested by French police.

After October 1940 the family situation deteriorated as the race laws descended into Vichy. Schweber and his family moved to Marseille and eventually made their way through Spain, Portugal, and Cuba before finally settling in the US in 1942. Largely self-taught through years on the wing, Schweber was fascinated by literature and music. In 1944 he enrolled in the City College of New York, where he began studying chemical engineering but eventually shifted to physics. From there he moved to the University of Pennsylvania and continued in physics with Walter Elsasser and Herbert Jehle. With his 1949 master’s degree in hand, he began his PhD work at Princeton University under the supervision of Arthur Wightman; he received his degree in 1952.

Without a doubt, the single greatest influence on Schweber was Hans Bethe, with whom he worked as a postdoc at Cornell University between 1952 and 1954. Along with Frederic de Hoffmann, Schweber and Bethe published Mesons and Fields (1955), one of the earliest textbooks to treat postwar developments in quantum field theory and renormalization. Schweber expanded on that material in his 1961 textbook An Introduction to Relativistic Quantum Field Theory; a 2005 edition remains in print today. Following his work with Bethe, Schweber joined the physics department faculty at Brandeis University in 1955, where he spent the rest of his career and served three times as department chair.

Building on his experience as a theoretical physicist and textbook author, in the early 1980s Schweber began to explore the history of science. His first forays examined relations among 19th-century astronomers, economists, and naturalist Charles Darwin, but soon he began to investigate the history of quantum field theory. From the start of his work in the history of science, Schweber sought to understand technical developments within broader intellectual and institutional contexts. Those developments include the first successful efforts in the late 1940s to “renormalize” the infinities that had long plagued field-theoretic calculations. Schweber’s investigations culminated in his masterful 1994 book QED and the Men Who Made It: Dyson, Feynman, Schwinger, and Tomonaga, which remains the most thorough account of one of the great successes of modern physics.

In Schweber’s telling, young physicists like Julian Schwinger and Feynman succeeded because their intense efforts were embedded within a particular infrastructure. For example, unlike prevailing traditions in other countries at the time, physics departments in US universities housed theoretical and experimental physicists together, an arrangement that fostered close interactions between them. Those close ties were buttressed by massive World War II military projects such as radar and the Manhattan Project, which reinforced many American physicists’ pragmatic approaches and underscored the need for theorists to “get the numbers out” rather than get distracted by formal niceties. Members of Schwinger’s and Feynman’s generation, joined by émigrés like Freeman Dyson from the UK, further benefited from strong postwar government support, including for new conferences and postdoctoral opportunities, to nurture and grow the nascent community of US-based theoretical physicists. In Schweber’s reconstruction, original ideas about virtual particles and recalcitrant integrals thus unfolded against a specific historical backdrop.

After QED and the Men Who Made It, Schweber roamed across several domains of the history of physics. Much of his historical work centered around Bethe. Schweber’s 2012 biography, Nuclear Forces: The Making of the Physicist Hans Bethe, captures Schweber’s two favorite expressions of profound admiration: “off-scale,” referring to individuals’ intellectual capabilities, and “inner moral compass,” about their ethical sense.

In an earlier study, In the Shadow of the Bomb: Oppenheimer, Bethe, and the Moral Responsibility of the Scientist (2000), Schweber contrasted J. Robert Oppenheimer’s and Bethe’s responses to the weapon they helped create. (Oppenheimer headed the wartime Los Alamos laboratory; Bethe led its theory division.) In Schweber’s eyes, the contrast was profound: Bethe led a life of moral integrity, whereas Oppenheimer perpetually had to compromise to maintain as best he could his insider status in the halls of power. Schweber’s book Einstein and Oppenheimer: The Meaning of Genius (2008) sketches a different dyad, this time setting Einstein’s remoteness from postwar meson and quantum electrodynamics physics against Oppenheimer’s engagement.

Schweber received the American Physical Society’s Abraham Pais Prize for History of Physics in 2011. Members of several generations of historians of science, who worked closely with Schweber, recall him as a deeply committed mentor. He encouraged immersion in the science and never hesitated to speak out when he felt that history of science was straying from its best self.