Steven Weinberg
1933–2021, New York City, USA, Austin, Texas, USA
American theoretical physicist who unified the weak and electromagnetic interactions in a single electroweak gauge theory predicting the W and Z bosons.
A Bronx High School of Science classmate of Glashow, Weinberg took his doctorate at Princeton and in 1967 inserted the SU(2)×U(1) structure into a lepton theory, invoking spontaneous symmetry breaking to give the W and Z their masses while keeping the photon massless. Initially little cited — it seemed non-renormalizable — the model triumphed after 't Hooft's 1971 proof and the discovery of neutral currents and the W and Z at CERN. His three-volume Quantum Theory of Fields and the bestselling The First Three Minutes made him the era's leading expositor of fundamental physics.
Nobel-winning work
Weinberg shared the 1979 Nobel Prize 'for contributions to the theory of the unified weak and electromagnetic interaction'. His 1967 paper 'A Model of Leptons' wrote down an SU(2)×U(1) gauge theory in which a spontaneously broken scalar field gives mass to the W⁺, W⁻ and Z⁰ while the photon stays massless — with the Z mass tied to the W by the Weinberg angle θ_W, sin²θ_W ≈ 0.23.
The theory predicted neutral weak currents (observed at CERN in 1973), the masses of the W and Z near 80 and 90 GeV (confirmed in 1983), and remains a pillar of the Standard Model.
Workplaces: University of Texas at Austin, Harvard University
United States