Stanislaw Ulam (1909 - 1984)
Stanislaw Marcin Ulam was born in Lvov, Austria-Hungary (now Ukraine). He was part of the city's Polish majority. His mentor in mathematics was Stefan Banach, a great Polish mathematician, one of the moving spirits of the Lvov School of Mathematics. Ulam received his Ph.D. in mathematics in 1933 at the Lvov Polytechnic Institute. Along with his younger brother Adam, he fled Poland in 1939. His friend, John von Neumann, had secured a position at the Institute of Advanced Studies in Princeton. The rest of Ulam's family was killed in the Holocaust.
Ulam went to the U.S. in 1938 as a Harvard Junior Fellow. When his fellowship was not renewed, he served on the faculty at the University of Wisconsin and supported his brother. While there, in the midst of the war, Ulam joined the Manhattan Project at Los Alamos, working with von Neumann at his invitation.
While there, Ulam suggested the Monte Carlo Method for evaluating complicated mathematical integrals that arise in the theory of nuclear chain reactions. This suggestion ed to the more systematic development of Monte Carlo by von Neumann, Metropolis and others, which greatly aided in solving many of the complex problems in creating an atomic bomb.
When President Truman announced that the U.S. was to develop a hydrogen bomb, Ulam began calculating whether Edward Teller's design would work. Ultimately, Ulam and fellow mathematician Cornelius Everett concluded that Teller's model would never work. The result caused tensions between Ulam and Teller. A year later, he accidentally came up with a new scheme that would prove to be a breakthrough.
After World War II, Ulam largely turned from rigorous pure mathematics to speculative and imaginative work, posing problems and making conjectures that often concerned eh application of mathematics to physics and biology. Many believed that this change was due to an attack of encephalitis in 1946 that Gian-Carlo Rota claimed changed Ulam's personality, although Ulam's widow Françoise and others rejected the idea.
Ulam took a position as chair of mathematics at the University of Colorado in 1965, but he remained a consultant at Los Alamos, dividing his time between Boulder, Colorado, and Santa Fe, New Mexico, from which he commuted to Los Alamos. Later, he and his wife spent winters in Gainesville, Florida, where he had a position with the University of Florida. He died in Santa Fe on May 13, 1984.