He was an American theoretical physicist who took every physics course at MIT. He had mastered calculus by the age of 15. He was the most brilliant and influential figure in his field. His interest was in subatomic physics. He was chosen as the group leader in the theoretical division to work on estimating how much uranium would be needed to achieve critical mass for Manhattan Project. He developed a simple notation to describe the complex behavior of subatomic particles. He also worked in the field of quantum electrodynamics and shared a Noble Prize in 1965.