Richar Phillips Feynman (IPA: /ˈfaɪnmən/; May 11, 1918 – February 15, 1988) was an American physicist known for the path integral formulation of quantum mechanics, the theory of quantum electrodynamics, the physics of the superfluidity of supercooled liquid helium, and particle theory. For his contributions to the development of quantum electrodynamics, Feynman was a joint recipient of the Nobel Prize in Physics in 1965, together with Julian Schwinger and Shin-Ichiro Tomonaga. Feynman developed a widely-used pictorial representation scheme for the mathematical expressions governing the behavior of subatomic particles, which later became known as Feynman diagrams.