Chen-ning Yang

Born October 1, 1922, Yang Chen-Ning built his career at the intersection of pure mathematics and physical law. In 1954, working with Robert Mills, he developed the non-abelian gauge theory that now bears both their names - a framework that would eventually describe the nuclear forces binding matter together. Two years later, he and Tsung-Dao Lee proposed that weak nuclear interactions violate parity, the mirror-symmetry that seemed to govern all other physics. The Wu experiment confirmed it in 1956, and the Nobel followed in 1957. Yang kept working across statistical mechanics, condensed matter, and integrable systems for decades after. He died October 18, 2025, at 103, having written equations that underpin how physicists see the forces of nature.