Marilyn Simons is president of the Simons Foundation, which supports advanced work in the basic sciences and mathematics, with a major emphasis on autism.
"Jim Simons is a man who knows a good investment when he sees one," said Gov. Eliot Spitzer, who appeared at a press conference announcing the gift.
Jim Simons headed Stony Brook's math department from 1968 to 1976. The university said that during his tenure, Simons and Dr. Chen Ning Yang, the 1957 winner of the Nobel Prize in Physics, led seminars promoting synergy between physic and mathematics.
The gift will be used to construct and endow the Simons Center for Geometry and Physics.
"From Archimedes to Newton to Einstein, much of the most profound work in physics has been deeply intertwined with the geometric side of mathematics," Simons said. "Since then, in particular with the advent of such areas as quantum field theory and string theory, developments in geometry and physics have become if anything more interrelated."
"The new center will give many of the world's best mathematicians and physicists the opportunity to work and interact in an environment and an architecture carefully designed to enhance progress," Simons said.
The money also will be used to recruit and retain faculty, train graduate students, fund research programs and secure visiting scholars.
The center said it already has "scored a recruiting coup" - string theorist Dr. Michael R. Douglas of Rutgers University.
Douglas is a native of Stony Brook. His father, Ronald G. Douglas, was on the math faculty under Simons and later worked in the university's administration.
"Jim and Marilyn Simons are people of remarkable vision," said Stony Brook President Shirley Strum Kenny. "They truly understand the critical need for support of education, particularly in science and mathematics, in America."