Sergio Fubini (December 31, 1928 – January 6, 2005) was an Italian theoretical physicist. He was one of the pioneers of string theory. Politically he engaged himself actively for peace in the Middle East.
Fubini was born in Turin, from where he fled in 1938 as a politically persecuted Jew into Switzerland. Starting from 1945 he attended the Lycée in Turin, where he studied physics and in 1950 graduated "cum laude." Afterwards he was an assistant in Turin. From 1954 to 1957 he was in the USA and from 1958 to 1967 at CERN in Geneva. In 1959 he became a professor for nuclear physics at University of Padua and in 1961 a professor for theoretical physics at University of Turin. From 1968 to 1973 he was at MIT, but however taught summer courses in Turin, and starting from 1973 again at the CERN, where he was from 1971 to 1980 member of the advisory board and had an important role in planning the Large Electron Positron Collider (LEP). At MIT he was with his pupil Gabriele Veneziano at the center of an active school of theoretical physicist with close connections to Italy (with one of the Italian INFN and MIT financed "Bruno Rossi" exchange programs). He and his co-workers did fundamental work in string theory. (Other well-known MIT colleagues at that time were Victor Weisskopf, who was recruited by Fubini to MIT, Steven Weinberg, Roman Jackiw.) From 1994 to 2001 he was a professor in Turin. Fubini worked in the 1960s on current algebras and S-matrix theory (Regge trajectories among other things), in particular on their field-theoretical foundations. In the 1970s he was with his MIT colleague and pupil Gabriele Veneziano one of the pioneers of string theory. He worked in the 1970s also among other things on classical solutions of Yang-Mills equations and conformally invariant quantum field theory (Nuovo Cimento 1976).
Fubini died in 2005 in Geneva. He was married since 1956 to Marina Colombo and had a daughter.