Leonard Susskind (born 1940) is the Felix Bloch professor of theoretical physics at Stanford University, whose research interests include string theory, quantum field theory, quantum statistical mechanics and quantum cosmology.
He is a member of the National Academy of Sciences, and the American Academy of Arts and Sciences, an associate member of the faculty of Canada's Perimeter Institute for Theoretical Physics, and a distinguished professor of the Korea Institute for Advanced Study. Susskind is widely regarded as one of the fathers of string theory, who with Yoichiro Nambu and Holger Bech Nielsen, independently introduced the idea that particles could in fact be states of excitation of a relativistic string. He was the first to introduce the idea of the string theory landscape in 2003. In 1997, Susskind was awarded the J.J. Sakurai Prize for his "pioneering contributions to hadronic string models, lattice gauge theories, quantum chromodynamics, and dynamical symmetry breaking".
Susskind's hallmark, according to colleagues, has been the application of "brilliant imagination and originality to the theoretical study of the nature of the elementary particles and forces that make up the physical world."
Susskind was born in a poor Jewish family from the South Bronx section of New York City, and now resides in Palo Alto, California. He began working as a plumber at the age of 16, taking over for his father who had become ill. Later, he enrolled in the City College of New York as an engineering student, graduating with a B.S. in physics in 1962. In an article with the Los Angeles Times, Susskind recalls the moment he discussed with his father this change in career path: "When I told my father I wanted to be a physicist, he said, ‘Hell no, you ain't going to work in a drug store.' I said no, not a pharmacist. I said, ‘Like Einstein.' He poked me in the chest with a piece of plumbing pipe. ‘You ain't going to be no engineer,' he said. ‘You're going to be Einstein.'" He then studied at Cornell University under Peter A. Carruthers where he received his Ph.D. in 1965. He has been married twice, originally in 1960, and has four children.
Susskind was an Assistant Professor of Physics, then an Associate Professor at Yeshiva University (1966–1970), after which he went for a year at the University of Tel Aviv (1971–72), returning to Yeshiva to become a Professor of Physics (1970–1979). Since 1979, he has been Professor of Physics at Stanford University, and since 2000, has held the Felix Bloch Professorship of Physics.
In 2007, Susskind joined the Faculty of Perimeter Institute for Theoretical Physics in Waterloo, Ontario, Canada, as an Associate Member. He has been elected to the National Academy of Sciences and the American Academy of Arts and Sciences, and was awarded the 1998 Sakurai Prize for theoretical physics. He is also a distinguished professor at Korea Institute for Advanced Study.
Susskind was one of at least three physicists who independently discovered during or around 1970 that the Veneziano dual resonance model of strong interactions could be described by a quantum mechanical model of strings, and was the first to propose the idea of the string theory landscape. Susskind has also made contributions in the following areas of physics:
The story goes that "In 1970, a young physicist named Leonard Susskind got stuck in an elevator with Murray Gell-Mann, one of physics' top theoreticians, who asked him what he was working on. Susskind said he was working on a theory that represented particles 'as some kind of elastic string, like a rubber band.' Gell-Mann responded with loud, derisive laughter."